From 52cb25070142f6648c759996cdafe992ae37d94a Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 27 Aug 2021 16:42:23 +0000
Subject: [PATCH 01/35] This is the handler we need to create.

---
 src/allmydata/web/status.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 158d897f9..8c78b1156 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -1551,6 +1551,21 @@ class Statistics(MultiFormatResource):
         req.setHeader("content-type", "text/plain")
         return json.dumps(stats, indent=1) + "\n"
 
+    @render_exception
+    def render_OPENMETRICS(self, req):
+        req.setHeader("content-type", "application/openmetrics-text")
+        return "3. occurence. This should be the one.\n"
+
+    # @render_exception
+    # def render_OPENMETRICS(self, req):
+    #     req.setHeader("content-type", "text/plain")
+    #     if self._helper:
+    #         stats = self._helper.get_stats()
+    #         import pprint
+    #         return pprint.PrettyPrinter().pprint(stats) + "\n"
+    #     return "uh oh\n"
+
+
 class StatisticsElement(Element):
 
     loader = XMLFile(FilePath(__file__).sibling("statistics.xhtml"))

From 4000116c244aaa6dda0c4cb87f7fc9bf7d332cb8 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 3 Sep 2021 13:42:09 +0000
Subject: [PATCH 02/35] Newsfragment for OpenMetrics endpoint

---
 newsfragments/3786.feature | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 newsfragments/3786.feature

diff --git a/newsfragments/3786.feature b/newsfragments/3786.feature
new file mode 100644
index 000000000..82ce3f974
--- /dev/null
+++ b/newsfragments/3786.feature
@@ -0,0 +1 @@
+tahoe-lafs now provides its statistics also in OpenMetrics format (for Prometheus et. al.) on `/statistics?t=openmetrics`.

From 8a64f50b79cefb8d76ce6111b51290c255099caf Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 3 Sep 2021 14:40:34 +0000
Subject: [PATCH 03/35] WIP - Could be wronger

---
 src/allmydata/web/status.py | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 8c78b1156..741f93061 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -14,6 +14,7 @@ from past.builtins import long
 
 import itertools
 import hashlib
+import re
 from twisted.internet import defer
 from twisted.python.filepath import FilePath
 from twisted.web.resource import Resource
@@ -1553,18 +1554,22 @@ class Statistics(MultiFormatResource):
 
     @render_exception
     def render_OPENMETRICS(self, req):
-        req.setHeader("content-type", "application/openmetrics-text")
-        return "3. occurence. This should be the one.\n"
+        def mangle_name(name):
+            return re.sub(
+                "_(\d\d)_(\d)_percentile",
+                '{quantile="0.\g<1>\g<2>"}',
+                name.replace(".", "_")
+            )
 
-    # @render_exception
-    # def render_OPENMETRICS(self, req):
-    #     req.setHeader("content-type", "text/plain")
-    #     if self._helper:
-    #         stats = self._helper.get_stats()
-    #         import pprint
-    #         return pprint.PrettyPrinter().pprint(stats) + "\n"
-    #     return "uh oh\n"
+        req.setHeader(
+            "content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8"
+        )
 
+        stats = self._provider.get_stats()
+        return (str({mangle_name(k): v for k, v in stats['counters'].items()})
+                + str({mangle_name(k): v for k, v in stats['stats'].items()})
+                + "\n"
+        )
 
 class StatisticsElement(Element):
 

From 2dbb9434b0d10b086e6d5367087aa1a4cdd77be0 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 8 Sep 2021 14:54:57 +0000
Subject: [PATCH 04/35] OpenMetrics endpoint WIP

---
 src/allmydata/web/status.py | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 741f93061..7d3fdd06e 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -1554,6 +1554,10 @@ class Statistics(MultiFormatResource):
 
     @render_exception
     def render_OPENMETRICS(self, req):
+        req.setHeader("content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8")
+        stats = self._provider.get_stats()
+        ret = u""
+
         def mangle_name(name):
             return re.sub(
                 "_(\d\d)_(\d)_percentile",
@@ -1561,15 +1565,13 @@ class Statistics(MultiFormatResource):
                 name.replace(".", "_")
             )
 
-        req.setHeader(
-            "content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8"
-        )
+        for (k, v) in sorted(stats['counters'].items()):
+            ret += u"tahoe_counters_%s %s\n" % (mangle_name(k), v)
 
-        stats = self._provider.get_stats()
-        return (str({mangle_name(k): v for k, v in stats['counters'].items()})
-                + str({mangle_name(k): v for k, v in stats['stats'].items()})
-                + "\n"
-        )
+        for (k, v) in sorted(stats['stats'].items()):
+            ret += u"tahoe_stats_%s %s\n" % (mangle_name(k), v)
+
+        return ret
 
 class StatisticsElement(Element):
 

From ca865e60db6d94bba6abb749a2db196a77b25d36 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 8 Sep 2021 15:08:25 +0000
Subject: [PATCH 05/35] OpenMetrics endpoint

---
 src/allmydata/web/status.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 7d3fdd06e..4be935a54 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -1565,12 +1565,13 @@ class Statistics(MultiFormatResource):
                 name.replace(".", "_")
             )
 
+        def mangle_value(val):
+            return str(val) if val is not None else "NaN"
+
         for (k, v) in sorted(stats['counters'].items()):
-            ret += u"tahoe_counters_%s %s\n" % (mangle_name(k), v)
-
+            ret += u"tahoe_counters_%s %s\n" % (mangle_name(k), mangle_value(v))
         for (k, v) in sorted(stats['stats'].items()):
-            ret += u"tahoe_stats_%s %s\n" % (mangle_name(k), v)
-
+            ret += u"tahoe_stats_%s %s\n" % (mangle_name(k), mangle_value(v))
         return ret
 
 class StatisticsElement(Element):

From 4674bccde799be427c20dcfa8cc133126b620b99 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Thu, 9 Sep 2021 13:54:03 +0000
Subject: [PATCH 06/35] OpenMetrics: add trailing EOF marker

---
 src/allmydata/web/status.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 4be935a54..3e0e1a3ee 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -1572,6 +1572,9 @@ class Statistics(MultiFormatResource):
             ret += u"tahoe_counters_%s %s\n" % (mangle_name(k), mangle_value(v))
         for (k, v) in sorted(stats['stats'].items()):
             ret += u"tahoe_stats_%s %s\n" % (mangle_name(k), mangle_value(v))
+
+        ret += u"# EOF\n"
+
         return ret
 
 class StatisticsElement(Element):

From d05e373d4236f7e5a106120da11882b64abd7ded Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Thu, 9 Sep 2021 13:57:59 +0000
Subject: [PATCH 07/35] OpenMetrics: All strings are unicode.

---
 src/allmydata/web/status.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 3e0e1a3ee..6d36861ad 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -1560,13 +1560,13 @@ class Statistics(MultiFormatResource):
 
         def mangle_name(name):
             return re.sub(
-                "_(\d\d)_(\d)_percentile",
-                '{quantile="0.\g<1>\g<2>"}',
-                name.replace(".", "_")
+                u"_(\d\d)_(\d)_percentile",
+                u'{quantile="0.\g<1>\g<2>"}',
+                name.replace(u".", u"_")
             )
 
         def mangle_value(val):
-            return str(val) if val is not None else "NaN"
+            return str(val) if val is not None else u"NaN"
 
         for (k, v) in sorted(stats['counters'].items()):
             ret += u"tahoe_counters_%s %s\n" % (mangle_name(k), mangle_value(v))

From 74965b271c026fe35436207a3d358ff9c40b32dc Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Thu, 9 Sep 2021 22:36:30 +0000
Subject: [PATCH 08/35] typo

---
 newsfragments/3786.feature | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/newsfragments/3786.feature b/newsfragments/3786.feature
index 82ce3f974..ecbfc0372 100644
--- a/newsfragments/3786.feature
+++ b/newsfragments/3786.feature
@@ -1 +1 @@
-tahoe-lafs now provides its statistics also in OpenMetrics format (for Prometheus et. al.) on `/statistics?t=openmetrics`.
+tahoe-lafs now provides its statistics also in OpenMetrics format (for Prometheus et. al.) at `/statistics?t=openmetrics`.

From 30771149fc7467fd7a61076b1572bcfddaa9a218 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Thu, 9 Sep 2021 23:31:39 +0000
Subject: [PATCH 09/35] Openmetrics: Add test case scaffold

---
 src/allmydata/test/test_openmetrics.py | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 src/allmydata/test/test_openmetrics.py

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
new file mode 100644
index 000000000..ad11f3468
--- /dev/null
+++ b/src/allmydata/test/test_openmetrics.py
@@ -0,0 +1,11 @@
+from twisted.trial import unittest
+
+class FakeStatsProvider(object):
+    def get_stats(self):
+        stats = {'stats': {}, 'counters': {}}
+        return stats
+
+class OpenMetrics(unittest.TestCase):
+    def test_spec_compliance(self):
+        self.assertEqual('1', '2')
+

From fca1482b35b2360d07ec700c0a22d20162bc5acb Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 10 Sep 2021 00:10:11 +0000
Subject: [PATCH 10/35] OpenMetrics Tests WIP

---
 src/allmydata/test/test_openmetrics.py | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index ad11f3468..2211c3561 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -1,4 +1,6 @@
+import mock
 from twisted.trial import unittest
+from allmydata.web.status import Statistics
 
 class FakeStatsProvider(object):
     def get_stats(self):
@@ -6,6 +8,18 @@ class FakeStatsProvider(object):
         return stats
 
 class OpenMetrics(unittest.TestCase):
-    def test_spec_compliance(self):
-        self.assertEqual('1', '2')
+    def test_header(self):
+        req = mock.Mock()
+        stats = mock.Mock()
+        stats._provider = FakeStatsProvider()
+        metrics = Statistics.render_OPENMETRICS(stats, req)
+        req.setHeader.assert_called_with("content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8")
+
+    def test_spec_compliance(self):
+        req = mock.Mock()
+        stats = mock.Mock()
+        stats._provider = FakeStatsProvider()
+        metrics = Statistics.render_OPENMETRICS(stats, req)
+        # TODO test that output adheres to spec
+        # TODO add more realistic stats, incl. missing (None) values
 

From d04157d18a0fbe9a1832f94bf352b04e931039e1 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 10 Sep 2021 13:00:15 +0000
Subject: [PATCH 11/35] OpenMetrics test: Add parser to check against spec

---
 src/allmydata/test/test_openmetrics.py | 18 +++++++++++-------
 tox.ini                                |  2 ++
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 2211c3561..cd5c5d407 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -1,4 +1,5 @@
 import mock
+from prometheus_client.openmetrics import parser
 from twisted.trial import unittest
 from allmydata.web.status import Statistics
 
@@ -8,18 +9,21 @@ class FakeStatsProvider(object):
         return stats
 
 class OpenMetrics(unittest.TestCase):
-    def test_header(self):
+    def test_spec_compliance(self):
+        """
+        Does our output adhere to the OpenMetrics spec?
+        https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md
+        """
         req = mock.Mock()
         stats = mock.Mock()
         stats._provider = FakeStatsProvider()
         metrics = Statistics.render_OPENMETRICS(stats, req)
+
+        # "The content type MUST be..."
         req.setHeader.assert_called_with("content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8")
 
-    def test_spec_compliance(self):
-        req = mock.Mock()
-        stats = mock.Mock()
-        stats._provider = FakeStatsProvider()
-        metrics = Statistics.render_OPENMETRICS(stats, req)
-        # TODO test that output adheres to spec
+        # The parser throws if it can't parse.
+        # Wrap in a list() to drain the generator.
+        families = list(parser.text_string_to_metric_families(metrics))
         # TODO add more realistic stats, incl. missing (None) values
 
diff --git a/tox.ini b/tox.ini
index 9b0f71038..0e8e58ea6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -52,6 +52,8 @@ deps =
      certifi
      # VCS hooks support
      py36,!coverage: pre-commit
+     # Does our OpenMetrics endpoint adhere to the spec:
+     prometheus-client==0.11.0
 
 # We add usedevelop=False because testing against a true installation gives
 # more useful results.

From 6c18983f7b182fe696dd466dab517312692c1648 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 10 Sep 2021 13:13:13 +0000
Subject: [PATCH 12/35] OpenMetrics test: Use realistic input data

---
 src/allmydata/test/test_openmetrics.py | 92 +++++++++++++++++++++++++-
 1 file changed, 89 insertions(+), 3 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index cd5c5d407..c7e26213a 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -5,7 +5,95 @@ from allmydata.web.status import Statistics
 
 class FakeStatsProvider(object):
     def get_stats(self):
-        stats = {'stats': {}, 'counters': {}}
+        # Parsed into a dict from a running tahoe's /statistics?t=json
+        stats = {'stats': {
+           'storage_server.latencies.get.99_9_percentile': None,
+           'storage_server.latencies.close.10_0_percentile': 0.00021910667419433594,
+           'storage_server.latencies.read.01_0_percentile': 2.8848648071289062e-05,
+           'storage_server.latencies.writev.99_9_percentile': None,
+           'storage_server.latencies.read.99_9_percentile': None,
+           'storage_server.latencies.allocate.99_0_percentile': 0.000988006591796875,
+           'storage_server.latencies.writev.mean': 0.00045332245070571654,
+           'storage_server.latencies.close.99_9_percentile': None,
+           'cpu_monitor.15min_avg': 0.00017592000079223033,
+           'storage_server.disk_free_for_root': 103289454592,
+           'storage_server.latencies.get.99_0_percentile': 0.000347137451171875,
+           'storage_server.latencies.get.mean': 0.00021158285060171353,
+           'storage_server.latencies.read.90_0_percentile': 8.893013000488281e-05,
+           'storage_server.latencies.write.01_0_percentile': 3.600120544433594e-05,
+           'storage_server.latencies.write.99_9_percentile': 0.00017690658569335938,
+           'storage_server.latencies.close.90_0_percentile': 0.00033211708068847656,
+           'storage_server.disk_total': 103497859072,
+           'storage_server.latencies.close.95_0_percentile': 0.0003509521484375,
+           'storage_server.latencies.readv.samplesize': 1000,
+           'storage_server.disk_free_for_nonroot': 103289454592,
+           'storage_server.latencies.close.mean': 0.0002715024480059103,
+           'storage_server.latencies.writev.95_0_percentile': 0.0007410049438476562,
+           'storage_server.latencies.readv.90_0_percentile': 0.0003781318664550781,
+           'storage_server.latencies.readv.99_0_percentile': 0.0004050731658935547,
+           'storage_server.latencies.allocate.mean': 0.0007128627429454784,
+           'storage_server.latencies.close.samplesize': 326,
+           'storage_server.latencies.get.50_0_percentile': 0.0001819133758544922,
+           'storage_server.latencies.write.50_0_percentile': 4.482269287109375e-05,
+           'storage_server.latencies.readv.01_0_percentile': 0.0002970695495605469,
+           'storage_server.latencies.get.10_0_percentile': 0.00015687942504882812,
+           'storage_server.latencies.allocate.90_0_percentile': 0.0008189678192138672,
+           'storage_server.latencies.get.samplesize': 472,
+           'storage_server.total_bucket_count': 393,
+           'storage_server.latencies.read.mean': 5.936201880959903e-05,
+           'storage_server.latencies.allocate.01_0_percentile': 0.0004208087921142578,
+           'storage_server.latencies.allocate.99_9_percentile': None,
+           'storage_server.latencies.readv.mean': 0.00034061360359191893,
+           'storage_server.disk_used': 208404480,
+           'storage_server.latencies.allocate.50_0_percentile': 0.0007410049438476562,
+           'storage_server.latencies.read.99_0_percentile': 0.00011992454528808594,
+           'node.uptime': 3805759.8545179367,
+           'storage_server.latencies.writev.10_0_percentile': 0.00035190582275390625,
+           'storage_server.latencies.writev.90_0_percentile': 0.0006821155548095703,
+           'storage_server.latencies.close.01_0_percentile': 0.00021505355834960938,
+           'storage_server.latencies.close.50_0_percentile': 0.0002579689025878906,
+           'cpu_monitor.1min_avg': 0.0002130000000003444,
+           'storage_server.latencies.writev.50_0_percentile': 0.0004138946533203125,
+           'storage_server.latencies.read.95_0_percentile': 9.107589721679688e-05,
+           'storage_server.latencies.readv.95_0_percentile': 0.0003859996795654297,
+           'storage_server.latencies.write.10_0_percentile': 3.719329833984375e-05,
+           'storage_server.accepting_immutable_shares': 1,
+           'storage_server.latencies.writev.samplesize': 309,
+           'storage_server.latencies.get.95_0_percentile': 0.0003190040588378906,
+           'storage_server.latencies.readv.10_0_percentile': 0.00032210350036621094,
+           'storage_server.latencies.get.90_0_percentile': 0.0002999305725097656,
+           'storage_server.latencies.get.01_0_percentile': 0.0001239776611328125,
+           'cpu_monitor.total': 641.4941180000001,
+           'storage_server.latencies.write.samplesize': 1000,
+           'storage_server.latencies.write.95_0_percentile': 9.489059448242188e-05,
+           'storage_server.latencies.read.50_0_percentile': 6.890296936035156e-05,
+           'storage_server.latencies.writev.01_0_percentile': 0.00033211708068847656,
+           'storage_server.latencies.read.10_0_percentile': 3.0994415283203125e-05,
+           'storage_server.latencies.allocate.10_0_percentile': 0.0004949569702148438,
+           'storage_server.reserved_space': 0,
+           'storage_server.disk_avail': 103289454592,
+           'storage_server.latencies.write.99_0_percentile': 0.00011301040649414062,
+           'storage_server.latencies.write.90_0_percentile': 9.083747863769531e-05,
+           'cpu_monitor.5min_avg': 0.0002370666691157502,
+           'storage_server.latencies.write.mean': 5.8008909225463864e-05,
+           'storage_server.latencies.readv.50_0_percentile': 0.00033020973205566406,
+           'storage_server.latencies.close.99_0_percentile': 0.0004038810729980469,
+           'storage_server.allocated': 0,
+           'storage_server.latencies.writev.99_0_percentile': 0.0007710456848144531,
+           'storage_server.latencies.readv.99_9_percentile': 0.0004780292510986328,
+           'storage_server.latencies.read.samplesize': 170,
+           'storage_server.latencies.allocate.samplesize': 406,
+           'storage_server.latencies.allocate.95_0_percentile': 0.0008411407470703125
+         }, 'counters': {
+           'storage_server.writev': 309,
+           'storage_server.bytes_added': 197836146,
+           'storage_server.close': 326,
+           'storage_server.readv': 14299,
+           'storage_server.allocate': 406,
+           'storage_server.read': 170,
+           'storage_server.write': 3775,
+           'storage_server.get': 472}
+         }
         return stats
 
 class OpenMetrics(unittest.TestCase):
@@ -25,5 +113,3 @@ class OpenMetrics(unittest.TestCase):
         # The parser throws if it can't parse.
         # Wrap in a list() to drain the generator.
         families = list(parser.text_string_to_metric_families(metrics))
-        # TODO add more realistic stats, incl. missing (None) values
-

From 339e1747e7b2636a49c4155f9786e79fdb37de3f Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 10 Sep 2021 13:15:56 +0000
Subject: [PATCH 13/35] clean up

---
 src/allmydata/test/test_openmetrics.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index c7e26213a..9ef7c9c8e 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -108,8 +108,10 @@ class OpenMetrics(unittest.TestCase):
         metrics = Statistics.render_OPENMETRICS(stats, req)
 
         # "The content type MUST be..."
-        req.setHeader.assert_called_with("content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8")
+        req.setHeader.assert_called_with(
+            "content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8"
+        )
 
-        # The parser throws if it can't parse.
-        # Wrap in a list() to drain the generator.
+        # The parser throws if it does not like its input.
+        # Wrapped in a list() to drain the generator.
         families = list(parser.text_string_to_metric_families(metrics))

From ad84f5df2b9310df2fac25c5dc989c4044af491b Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 10 Sep 2021 13:21:06 +0000
Subject: [PATCH 14/35] newline at the end.

---
 src/allmydata/test/test_openmetrics.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 9ef7c9c8e..fdb645b42 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -115,3 +115,4 @@ class OpenMetrics(unittest.TestCase):
         # The parser throws if it does not like its input.
         # Wrapped in a list() to drain the generator.
         families = list(parser.text_string_to_metric_families(metrics))
+

From 88a2e7a4fb993fb28a14a6cfe1ac1025a998bb93 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 10:09:55 +0000
Subject: [PATCH 15/35] OpenMetrics test suite: Get rid of status mock

---
 src/allmydata/test/test_openmetrics.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index fdb645b42..57ed989e0 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -96,6 +96,10 @@ class FakeStatsProvider(object):
          }
         return stats
 
+class FakeStats():
+    def __init__(self):
+        self._provider = FakeStatsProvider()
+
 class OpenMetrics(unittest.TestCase):
     def test_spec_compliance(self):
         """
@@ -103,8 +107,7 @@ class OpenMetrics(unittest.TestCase):
         https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md
         """
         req = mock.Mock()
-        stats = mock.Mock()
-        stats._provider = FakeStatsProvider()
+        stats = FakeStats()
         metrics = Statistics.render_OPENMETRICS(stats, req)
 
         # "The content type MUST be..."

From 57a3c1168e98fbce9b6b10d8a20100f4384a1620 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 11:03:31 +0000
Subject: [PATCH 16/35] OpenMetrics: Use list of strings instead of string
 concatenation

---
 src/allmydata/web/status.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 6d36861ad..2542ca75f 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -1556,7 +1556,7 @@ class Statistics(MultiFormatResource):
     def render_OPENMETRICS(self, req):
         req.setHeader("content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8")
         stats = self._provider.get_stats()
-        ret = u""
+        ret = []
 
         def mangle_name(name):
             return re.sub(
@@ -1569,13 +1569,13 @@ class Statistics(MultiFormatResource):
             return str(val) if val is not None else u"NaN"
 
         for (k, v) in sorted(stats['counters'].items()):
-            ret += u"tahoe_counters_%s %s\n" % (mangle_name(k), mangle_value(v))
+            ret.append(u"tahoe_counters_%s %s" % (mangle_name(k), mangle_value(v)))
         for (k, v) in sorted(stats['stats'].items()):
-            ret += u"tahoe_stats_%s %s\n" % (mangle_name(k), mangle_value(v))
+            ret.append(u"tahoe_stats_%s %s" % (mangle_name(k), mangle_value(v)))
 
-        ret += u"# EOF\n"
+        ret.append(u"# EOF")
 
-        return ret
+        return u"\n".join(ret)
 
 class StatisticsElement(Element):
 

From d864cab5b0861a7c4a4caec294bafac884f318a6 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 11:14:52 +0000
Subject: [PATCH 17/35] OpenMetrics: Add test dep to nix packaging

---
 nix/tahoe-lafs.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/nix/tahoe-lafs.nix b/nix/tahoe-lafs.nix
index 35b29f1cc..17b2f4463 100644
--- a/nix/tahoe-lafs.nix
+++ b/nix/tahoe-lafs.nix
@@ -107,6 +107,7 @@ EOF
     beautifulsoup4
     html5lib
     tenacity
+    prometheus_client
   ];
 
   checkPhase = ''

From c66ae302c8412365c0f3848298351a1d69d975d8 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 11:26:30 +0000
Subject: [PATCH 18/35] OpenMetrics: Extra newline at the end

---
 src/allmydata/web/status.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 2542ca75f..7b16a60b2 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -1573,7 +1573,7 @@ class Statistics(MultiFormatResource):
         for (k, v) in sorted(stats['stats'].items()):
             ret.append(u"tahoe_stats_%s %s" % (mangle_name(k), mangle_value(v)))
 
-        ret.append(u"# EOF")
+        ret.append(u"# EOF\n")
 
         return u"\n".join(ret)
 

From cbe5ea1115e3e77e86d69a4dc2b29e508724e18e Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 11:28:39 +0000
Subject: [PATCH 19/35] OpenMetrics: Add docstring

---
 src/allmydata/web/status.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/allmydata/web/status.py b/src/allmydata/web/status.py
index 7b16a60b2..65647f491 100644
--- a/src/allmydata/web/status.py
+++ b/src/allmydata/web/status.py
@@ -1554,6 +1554,12 @@ class Statistics(MultiFormatResource):
 
     @render_exception
     def render_OPENMETRICS(self, req):
+        """
+        Render our stats in `OpenMetrics <https://openmetrics.io/>` format.
+        For example Prometheus and Victoriametrics can parse this.
+        Point the scraper to ``/statistics?t=openmetrics`` (instead of the
+        default ``/metrics``).
+        """
         req.setHeader("content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8")
         stats = self._provider.get_stats()
         ret = []

From 21c471ed8113ce29fd1b6c6dc02e2acf124d550a Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 11:39:32 +0000
Subject: [PATCH 20/35] OpenMetrics test: Add hopefully more stable URIs to
 OpenMetrics spec info

---
 src/allmydata/test/test_openmetrics.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 57ed989e0..7753960d4 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -103,8 +103,9 @@ class FakeStats():
 class OpenMetrics(unittest.TestCase):
     def test_spec_compliance(self):
         """
-        Does our output adhere to the OpenMetrics spec?
-        https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md
+        Does our output adhere to the `OpenMetrics <https://openmetrics.io/>` spec?
+        https://github.com/OpenObservability/OpenMetrics/
+        https://prometheus.io/docs/instrumenting/exposition_formats/
         """
         req = mock.Mock()
         stats = FakeStats()

From 6bcff5472b9aca6dd09e585e80bb937832d254e7 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 11:50:20 +0000
Subject: [PATCH 21/35] OpenMetrics test suite: Add a check to see whether our
 stats were parsed at all.

---
 src/allmydata/test/test_openmetrics.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 7753960d4..a9a0e5712 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -120,3 +120,7 @@ class OpenMetrics(unittest.TestCase):
         # Wrapped in a list() to drain the generator.
         families = list(parser.text_string_to_metric_families(metrics))
 
+        # Has the parser parsed our data?
+        # Just check the last item.
+        self.assertEqual(families[-1].name, u"tahoe_stats_storage_server_total_bucket_count")
+

From 383ab4729a7c362f25526097c3f6c66e9451ef2c Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 11:53:48 +0000
Subject: [PATCH 22/35] OpenMetrics tests: Tryfix resolve TypeError on CI

Was:
> TypeError: unbound method render_OPENMETRICS() must be called with Statistics instance as first argument (got FakeStats instance instead)
---
 src/allmydata/test/test_openmetrics.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index a9a0e5712..9c840714c 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -96,7 +96,7 @@ class FakeStatsProvider(object):
          }
         return stats
 
-class FakeStats():
+class FakeStats(Statistics):
     def __init__(self):
         self._provider = FakeStatsProvider()
 

From b0e1cf924d44b271314efac94106247afdc7be10 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Wed, 15 Sep 2021 15:14:29 +0000
Subject: [PATCH 23/35] OpenMetrics test: White space only: Format JSON fixture
 to be easier on the eyes

---
 src/allmydata/test/test_openmetrics.py | 177 +++++++++++++------------
 1 file changed, 89 insertions(+), 88 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 9c840714c..7d9bd6429 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -6,94 +6,95 @@ from allmydata.web.status import Statistics
 class FakeStatsProvider(object):
     def get_stats(self):
         # Parsed into a dict from a running tahoe's /statistics?t=json
-        stats = {'stats': {
-           'storage_server.latencies.get.99_9_percentile': None,
-           'storage_server.latencies.close.10_0_percentile': 0.00021910667419433594,
-           'storage_server.latencies.read.01_0_percentile': 2.8848648071289062e-05,
-           'storage_server.latencies.writev.99_9_percentile': None,
-           'storage_server.latencies.read.99_9_percentile': None,
-           'storage_server.latencies.allocate.99_0_percentile': 0.000988006591796875,
-           'storage_server.latencies.writev.mean': 0.00045332245070571654,
-           'storage_server.latencies.close.99_9_percentile': None,
-           'cpu_monitor.15min_avg': 0.00017592000079223033,
-           'storage_server.disk_free_for_root': 103289454592,
-           'storage_server.latencies.get.99_0_percentile': 0.000347137451171875,
-           'storage_server.latencies.get.mean': 0.00021158285060171353,
-           'storage_server.latencies.read.90_0_percentile': 8.893013000488281e-05,
-           'storage_server.latencies.write.01_0_percentile': 3.600120544433594e-05,
-           'storage_server.latencies.write.99_9_percentile': 0.00017690658569335938,
-           'storage_server.latencies.close.90_0_percentile': 0.00033211708068847656,
-           'storage_server.disk_total': 103497859072,
-           'storage_server.latencies.close.95_0_percentile': 0.0003509521484375,
-           'storage_server.latencies.readv.samplesize': 1000,
-           'storage_server.disk_free_for_nonroot': 103289454592,
-           'storage_server.latencies.close.mean': 0.0002715024480059103,
-           'storage_server.latencies.writev.95_0_percentile': 0.0007410049438476562,
-           'storage_server.latencies.readv.90_0_percentile': 0.0003781318664550781,
-           'storage_server.latencies.readv.99_0_percentile': 0.0004050731658935547,
-           'storage_server.latencies.allocate.mean': 0.0007128627429454784,
-           'storage_server.latencies.close.samplesize': 326,
-           'storage_server.latencies.get.50_0_percentile': 0.0001819133758544922,
-           'storage_server.latencies.write.50_0_percentile': 4.482269287109375e-05,
-           'storage_server.latencies.readv.01_0_percentile': 0.0002970695495605469,
-           'storage_server.latencies.get.10_0_percentile': 0.00015687942504882812,
-           'storage_server.latencies.allocate.90_0_percentile': 0.0008189678192138672,
-           'storage_server.latencies.get.samplesize': 472,
-           'storage_server.total_bucket_count': 393,
-           'storage_server.latencies.read.mean': 5.936201880959903e-05,
-           'storage_server.latencies.allocate.01_0_percentile': 0.0004208087921142578,
-           'storage_server.latencies.allocate.99_9_percentile': None,
-           'storage_server.latencies.readv.mean': 0.00034061360359191893,
-           'storage_server.disk_used': 208404480,
-           'storage_server.latencies.allocate.50_0_percentile': 0.0007410049438476562,
-           'storage_server.latencies.read.99_0_percentile': 0.00011992454528808594,
-           'node.uptime': 3805759.8545179367,
-           'storage_server.latencies.writev.10_0_percentile': 0.00035190582275390625,
-           'storage_server.latencies.writev.90_0_percentile': 0.0006821155548095703,
-           'storage_server.latencies.close.01_0_percentile': 0.00021505355834960938,
-           'storage_server.latencies.close.50_0_percentile': 0.0002579689025878906,
-           'cpu_monitor.1min_avg': 0.0002130000000003444,
-           'storage_server.latencies.writev.50_0_percentile': 0.0004138946533203125,
-           'storage_server.latencies.read.95_0_percentile': 9.107589721679688e-05,
-           'storage_server.latencies.readv.95_0_percentile': 0.0003859996795654297,
-           'storage_server.latencies.write.10_0_percentile': 3.719329833984375e-05,
-           'storage_server.accepting_immutable_shares': 1,
-           'storage_server.latencies.writev.samplesize': 309,
-           'storage_server.latencies.get.95_0_percentile': 0.0003190040588378906,
-           'storage_server.latencies.readv.10_0_percentile': 0.00032210350036621094,
-           'storage_server.latencies.get.90_0_percentile': 0.0002999305725097656,
-           'storage_server.latencies.get.01_0_percentile': 0.0001239776611328125,
-           'cpu_monitor.total': 641.4941180000001,
-           'storage_server.latencies.write.samplesize': 1000,
-           'storage_server.latencies.write.95_0_percentile': 9.489059448242188e-05,
-           'storage_server.latencies.read.50_0_percentile': 6.890296936035156e-05,
-           'storage_server.latencies.writev.01_0_percentile': 0.00033211708068847656,
-           'storage_server.latencies.read.10_0_percentile': 3.0994415283203125e-05,
-           'storage_server.latencies.allocate.10_0_percentile': 0.0004949569702148438,
-           'storage_server.reserved_space': 0,
-           'storage_server.disk_avail': 103289454592,
-           'storage_server.latencies.write.99_0_percentile': 0.00011301040649414062,
-           'storage_server.latencies.write.90_0_percentile': 9.083747863769531e-05,
-           'cpu_monitor.5min_avg': 0.0002370666691157502,
-           'storage_server.latencies.write.mean': 5.8008909225463864e-05,
-           'storage_server.latencies.readv.50_0_percentile': 0.00033020973205566406,
-           'storage_server.latencies.close.99_0_percentile': 0.0004038810729980469,
-           'storage_server.allocated': 0,
-           'storage_server.latencies.writev.99_0_percentile': 0.0007710456848144531,
-           'storage_server.latencies.readv.99_9_percentile': 0.0004780292510986328,
-           'storage_server.latencies.read.samplesize': 170,
-           'storage_server.latencies.allocate.samplesize': 406,
-           'storage_server.latencies.allocate.95_0_percentile': 0.0008411407470703125
-         }, 'counters': {
-           'storage_server.writev': 309,
-           'storage_server.bytes_added': 197836146,
-           'storage_server.close': 326,
-           'storage_server.readv': 14299,
-           'storage_server.allocate': 406,
-           'storage_server.read': 170,
-           'storage_server.write': 3775,
-           'storage_server.get': 472}
-         }
+        stats = {
+          'stats': {
+            'storage_server.latencies.get.99_9_percentile': None,
+            'storage_server.latencies.close.10_0_percentile': 0.00021910667419433594,
+            'storage_server.latencies.read.01_0_percentile': 2.8848648071289062e-05,
+            'storage_server.latencies.writev.99_9_percentile': None,
+            'storage_server.latencies.read.99_9_percentile': None,
+            'storage_server.latencies.allocate.99_0_percentile': 0.000988006591796875,
+            'storage_server.latencies.writev.mean': 0.00045332245070571654,
+            'storage_server.latencies.close.99_9_percentile': None,
+            'cpu_monitor.15min_avg': 0.00017592000079223033,
+            'storage_server.disk_free_for_root': 103289454592,
+            'storage_server.latencies.get.99_0_percentile': 0.000347137451171875,
+            'storage_server.latencies.get.mean': 0.00021158285060171353,
+            'storage_server.latencies.read.90_0_percentile': 8.893013000488281e-05,
+            'storage_server.latencies.write.01_0_percentile': 3.600120544433594e-05,
+            'storage_server.latencies.write.99_9_percentile': 0.00017690658569335938,
+            'storage_server.latencies.close.90_0_percentile': 0.00033211708068847656,
+            'storage_server.disk_total': 103497859072,
+            'storage_server.latencies.close.95_0_percentile': 0.0003509521484375,
+            'storage_server.latencies.readv.samplesize': 1000,
+            'storage_server.disk_free_for_nonroot': 103289454592,
+            'storage_server.latencies.close.mean': 0.0002715024480059103,
+            'storage_server.latencies.writev.95_0_percentile': 0.0007410049438476562,
+            'storage_server.latencies.readv.90_0_percentile': 0.0003781318664550781,
+            'storage_server.latencies.readv.99_0_percentile': 0.0004050731658935547,
+            'storage_server.latencies.allocate.mean': 0.0007128627429454784,
+            'storage_server.latencies.close.samplesize': 326,
+            'storage_server.latencies.get.50_0_percentile': 0.0001819133758544922,
+            'storage_server.latencies.write.50_0_percentile': 4.482269287109375e-05,
+            'storage_server.latencies.readv.01_0_percentile': 0.0002970695495605469,
+            'storage_server.latencies.get.10_0_percentile': 0.00015687942504882812,
+            'storage_server.latencies.allocate.90_0_percentile': 0.0008189678192138672,
+            'storage_server.latencies.get.samplesize': 472,
+            'storage_server.total_bucket_count': 393,
+            'storage_server.latencies.read.mean': 5.936201880959903e-05,
+            'storage_server.latencies.allocate.01_0_percentile': 0.0004208087921142578,
+            'storage_server.latencies.allocate.99_9_percentile': None,
+            'storage_server.latencies.readv.mean': 0.00034061360359191893,
+            'storage_server.disk_used': 208404480,
+            'storage_server.latencies.allocate.50_0_percentile': 0.0007410049438476562,
+            'storage_server.latencies.read.99_0_percentile': 0.00011992454528808594,
+            'node.uptime': 3805759.8545179367,
+            'storage_server.latencies.writev.10_0_percentile': 0.00035190582275390625,
+            'storage_server.latencies.writev.90_0_percentile': 0.0006821155548095703,
+            'storage_server.latencies.close.01_0_percentile': 0.00021505355834960938,
+            'storage_server.latencies.close.50_0_percentile': 0.0002579689025878906,
+            'cpu_monitor.1min_avg': 0.0002130000000003444,
+            'storage_server.latencies.writev.50_0_percentile': 0.0004138946533203125,
+            'storage_server.latencies.read.95_0_percentile': 9.107589721679688e-05,
+            'storage_server.latencies.readv.95_0_percentile': 0.0003859996795654297,
+            'storage_server.latencies.write.10_0_percentile': 3.719329833984375e-05,
+            'storage_server.accepting_immutable_shares': 1,
+            'storage_server.latencies.writev.samplesize': 309,
+            'storage_server.latencies.get.95_0_percentile': 0.0003190040588378906,
+            'storage_server.latencies.readv.10_0_percentile': 0.00032210350036621094,
+            'storage_server.latencies.get.90_0_percentile': 0.0002999305725097656,
+            'storage_server.latencies.get.01_0_percentile': 0.0001239776611328125,
+            'cpu_monitor.total': 641.4941180000001,
+            'storage_server.latencies.write.samplesize': 1000,
+            'storage_server.latencies.write.95_0_percentile': 9.489059448242188e-05,
+            'storage_server.latencies.read.50_0_percentile': 6.890296936035156e-05,
+            'storage_server.latencies.writev.01_0_percentile': 0.00033211708068847656,
+            'storage_server.latencies.read.10_0_percentile': 3.0994415283203125e-05,
+            'storage_server.latencies.allocate.10_0_percentile': 0.0004949569702148438,
+            'storage_server.reserved_space': 0,
+            'storage_server.disk_avail': 103289454592,
+            'storage_server.latencies.write.99_0_percentile': 0.00011301040649414062,
+            'storage_server.latencies.write.90_0_percentile': 9.083747863769531e-05,
+            'cpu_monitor.5min_avg': 0.0002370666691157502,
+            'storage_server.latencies.write.mean': 5.8008909225463864e-05,
+            'storage_server.latencies.readv.50_0_percentile': 0.00033020973205566406,
+            'storage_server.latencies.close.99_0_percentile': 0.0004038810729980469,
+            'storage_server.allocated': 0,
+            'storage_server.latencies.writev.99_0_percentile': 0.0007710456848144531,
+            'storage_server.latencies.readv.99_9_percentile': 0.0004780292510986328,
+            'storage_server.latencies.read.samplesize': 170,
+            'storage_server.latencies.allocate.samplesize': 406,
+            'storage_server.latencies.allocate.95_0_percentile': 0.0008411407470703125},
+          'counters': {
+            'storage_server.writev': 309,
+            'storage_server.bytes_added': 197836146,
+            'storage_server.close': 326,
+            'storage_server.readv': 14299,
+            'storage_server.allocate': 406,
+            'storage_server.read': 170,
+            'storage_server.write': 3775,
+            'storage_server.get': 472}
+          }
         return stats
 
 class FakeStats(Statistics):

From 5825b8bd42328618dfdc9f7a2aa02dd761fe2887 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Thu, 16 Sep 2021 15:58:04 +0000
Subject: [PATCH 24/35] OpenMetrics: rework test suite with exarkun

---
 src/allmydata/test/test_openmetrics.py | 90 ++++++++++++++++++++------
 1 file changed, 72 insertions(+), 18 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 7d9bd6429..a0822d594 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -1,7 +1,25 @@
-import mock
 from prometheus_client.openmetrics import parser
-from twisted.trial import unittest
+
+from treq.testing import RequestTraversalAgent
+
+from twisted.web.http import OK
+from twisted.web.client import readBody    
+from twisted.web.resource import Resource
+
+from testtools.twistedsupport import succeeded
+from testtools.matchers import (
+    Always,
+    AfterPreprocessing,
+    Equals,
+    MatchesAll,
+    MatchesStructure,
+    MatchesPredicate,
+    )
+from testtools.content import text_content
+
 from allmydata.web.status import Statistics
+from allmydata.test.common import SyncTestCase
+
 
 class FakeStatsProvider(object):
     def get_stats(self):
@@ -97,31 +115,67 @@ class FakeStatsProvider(object):
           }
         return stats
 
-class FakeStats(Statistics):
-    def __init__(self):
-        self._provider = FakeStatsProvider()
+class HackItResource(Resource):
+    def getChildWithDefault(self, path, request):
+        request.fields = None
+        return Resource.getChildWithDefault(self, path, request)
 
-class OpenMetrics(unittest.TestCase):
+
+class OpenMetrics(SyncTestCase):
     def test_spec_compliance(self):
         """
         Does our output adhere to the `OpenMetrics <https://openmetrics.io/>` spec?
         https://github.com/OpenObservability/OpenMetrics/
         https://prometheus.io/docs/instrumenting/exposition_formats/
         """
-        req = mock.Mock()
-        stats = FakeStats()
-        metrics = Statistics.render_OPENMETRICS(stats, req)
+        root = HackItResource()
+        root.putChild(b"", Statistics(FakeStatsProvider())) 
+        rta = RequestTraversalAgent(root)
+        d = rta.request(b"GET", b"http://localhost/?t=openmetrics")
+        self.assertThat(d, succeeded(matches_stats(self)))
 
-        # "The content type MUST be..."
-        req.setHeader.assert_called_with(
-            "content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8"
+def matches_stats(testcase):
+    def add_detail(testcase):
+        def predicate(body):
+            testcase.addDetail("body", text_content(body))
+            return True
+        return predicate
+
+    return MatchesAll(
+        MatchesStructure(
+            code=Equals(OK),
+            # "The content type MUST be..."
+            headers=has_header("content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8"),
+        ),
+        AfterPreprocessing(
+            readBodyText,
+            succeeded(MatchesAll(
+                MatchesPredicate(add_detail(testcase), "%s dummy"),
+                parses_as_openmetrics(),
+            ))
         )
+    )
 
-        # The parser throws if it does not like its input.
-        # Wrapped in a list() to drain the generator.
-        families = list(parser.text_string_to_metric_families(metrics))
+def readBodyText(response):
+    d = readBody(response)
+    d.addCallback(lambda body: body.decode("utf-8"))
+    return d
+
+def has_header(name, value):
+    return AfterPreprocessing(
+        lambda headers: headers.getRawHeaders(name),
+        Equals([value]),
+    )
+
+def parses_as_openmetrics():
+    # The parser throws if it does not like its input.
+    # Wrapped in a list() to drain the generator. 
+    return AfterPreprocessing(
+        lambda body: list(parser.text_string_to_metric_families(body)),
+        AfterPreprocessing(
+            lambda families: families[-1].name, 
+            Equals(u"tahoe_stats_storage_server_total_bucket_count"),
+        ),
+    )
 
-        # Has the parser parsed our data?
-        # Just check the last item.
-        self.assertEqual(families[-1].name, u"tahoe_stats_storage_server_total_bucket_count")
 

From a2378d0e704add3741aa269adc37ac3f781ac36a Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 17 Sep 2021 12:04:12 +0000
Subject: [PATCH 25/35] OpenMetrics test suite: Make CI happy: No old style
 objects

---
 src/allmydata/test/test_openmetrics.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index a0822d594..43704c4a3 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -115,7 +115,7 @@ class FakeStatsProvider(object):
           }
         return stats
 
-class HackItResource(Resource):
+class HackItResource(Resource, object):
     def getChildWithDefault(self, path, request):
         request.fields = None
         return Resource.getChildWithDefault(self, path, request)

From fb0335cc17c709d5663f7ea2c31ccb98b6d6ddf1 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 17 Sep 2021 12:16:37 +0000
Subject: [PATCH 26/35] OpenMetrics test suite: More clean up

The Linter complains:
> 'testtools.matchers.Always' imported but unused
---
 src/allmydata/test/test_openmetrics.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 43704c4a3..91692af33 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -8,7 +8,6 @@ from twisted.web.resource import Resource
 
 from testtools.twistedsupport import succeeded
 from testtools.matchers import (
-    Always,
     AfterPreprocessing,
     Equals,
     MatchesAll,

From e5e0d71ef518c73e3fe2a0bc860e1c7428ba91a9 Mon Sep 17 00:00:00 2001
From: Florian Sesser <florian@private.storage>
Date: Fri, 17 Sep 2021 13:20:59 +0000
Subject: [PATCH 27/35] OpenMetrics test suite: More clean ups

trailing whitespace
---
 src/allmydata/test/test_openmetrics.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 91692af33..9677de4a9 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -3,7 +3,7 @@ from prometheus_client.openmetrics import parser
 from treq.testing import RequestTraversalAgent
 
 from twisted.web.http import OK
-from twisted.web.client import readBody    
+from twisted.web.client import readBody
 from twisted.web.resource import Resource
 
 from testtools.twistedsupport import succeeded
@@ -128,7 +128,7 @@ class OpenMetrics(SyncTestCase):
         https://prometheus.io/docs/instrumenting/exposition_formats/
         """
         root = HackItResource()
-        root.putChild(b"", Statistics(FakeStatsProvider())) 
+        root.putChild(b"", Statistics(FakeStatsProvider()))
         rta = RequestTraversalAgent(root)
         d = rta.request(b"GET", b"http://localhost/?t=openmetrics")
         self.assertThat(d, succeeded(matches_stats(self)))
@@ -168,11 +168,11 @@ def has_header(name, value):
 
 def parses_as_openmetrics():
     # The parser throws if it does not like its input.
-    # Wrapped in a list() to drain the generator. 
+    # Wrapped in a list() to drain the generator.
     return AfterPreprocessing(
         lambda body: list(parser.text_string_to_metric_families(body)),
         AfterPreprocessing(
-            lambda families: families[-1].name, 
+            lambda families: families[-1].name,
             Equals(u"tahoe_stats_storage_server_total_bucket_count"),
         ),
     )

From 5e26f25b3714167a628e93ae76a529b074fb4c69 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Thu, 23 Sep 2021 07:41:43 -0400
Subject: [PATCH 28/35] It's ported to Python 3!

---
 src/allmydata/test/test_openmetrics.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 9677de4a9..350d6abbd 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -1,3 +1,18 @@
+"""
+Tests for ``/statistics?t=openmetrics``.
+
+Ported to Python 3.
+"""
+
+from __future__ import print_function
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
+
 from prometheus_client.openmetrics import parser
 
 from treq.testing import RequestTraversalAgent

From f8c07bfd11edfee9b62b8bb13cbe46f643267322 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Thu, 23 Sep 2021 07:42:59 -0400
Subject: [PATCH 29/35] add some docstrings

---
 src/allmydata/test/test_openmetrics.py | 37 ++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 350d6abbd..34dcd266b 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -36,6 +36,10 @@ from allmydata.test.common import SyncTestCase
 
 
 class FakeStatsProvider(object):
+    """
+    A stats provider that hands backed a canned collection of performance
+    statistics.
+    """
     def get_stats(self):
         # Parsed into a dict from a running tahoe's /statistics?t=json
         stats = {
@@ -130,12 +134,21 @@ class FakeStatsProvider(object):
         return stats
 
 class HackItResource(Resource, object):
+    """
+    A bridge between ``RequestTraversalAgent`` and ``MultiFormatResource``
+    (used by ``Statistics``).  ``MultiFormatResource`` expects the request
+    object to have a ``fields`` attribute but Twisted's ``IRequest`` has no
+    such attribute.  Create it here.
+    """
     def getChildWithDefault(self, path, request):
         request.fields = None
         return Resource.getChildWithDefault(self, path, request)
 
 
 class OpenMetrics(SyncTestCase):
+    """
+    Tests for ``/statistics?t=openmetrics``.
+    """
     def test_spec_compliance(self):
         """
         Does our output adhere to the `OpenMetrics <https://openmetrics.io/>` spec?
@@ -171,17 +184,41 @@ def matches_stats(testcase):
     )
 
 def readBodyText(response):
+    """
+    Read the response body and decode it using UTF-8.
+
+    :param twisted.web.iweb.IResponse response: The response from which to
+        read the body.
+
+    :return: A ``Deferred`` that fires with the ``str`` body.
+    """
     d = readBody(response)
     d.addCallback(lambda body: body.decode("utf-8"))
     return d
 
 def has_header(name, value):
+    """
+    Create a matcher that matches a response object that includes the given
+    name / value pair.
+
+    :param str name: The name of the item in the HTTP header to match.
+    :param str value: The value of the item in the HTTP header to match by equality.
+
+    :return: A matcher.
+    """
     return AfterPreprocessing(
         lambda headers: headers.getRawHeaders(name),
         Equals([value]),
     )
 
 def parses_as_openmetrics():
+    """
+    Create a matcher that matches a ``str`` string that can be parsed as an
+    OpenMetrics response and includes a certain well-known value expected by
+    the tests.
+
+    :return: A matcher.
+    """
     # The parser throws if it does not like its input.
     # Wrapped in a list() to drain the generator.
     return AfterPreprocessing(

From 4d8164773c404373f4aeea37f2969680fa02c265 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Thu, 23 Sep 2021 07:43:18 -0400
Subject: [PATCH 30/35] factor helper function out to top-level

---
 src/allmydata/test/test_openmetrics.py | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 34dcd266b..a92098c88 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -162,11 +162,6 @@ class OpenMetrics(SyncTestCase):
         self.assertThat(d, succeeded(matches_stats(self)))
 
 def matches_stats(testcase):
-    def add_detail(testcase):
-        def predicate(body):
-            testcase.addDetail("body", text_content(body))
-            return True
-        return predicate
 
     return MatchesAll(
         MatchesStructure(
@@ -177,12 +172,26 @@ def matches_stats(testcase):
         AfterPreprocessing(
             readBodyText,
             succeeded(MatchesAll(
-                MatchesPredicate(add_detail(testcase), "%s dummy"),
+                MatchesPredicate(add_detail(testcase, u"response body"), u"%s dummy"),
                 parses_as_openmetrics(),
             ))
         )
     )
 
+def add_detail(testcase, name):
+    """
+    Create a matcher that always matches and as a side-effect adds the matched
+    value as detail to the testcase.
+
+    :param testtools.TestCase testcase: The case to which to add the detail.
+
+    :return: A matcher.
+    """
+    def predicate(value):
+        testcase.addDetail(name, text_content(value))
+        return True
+    return predicate
+
 def readBodyText(response):
     """
     Read the response body and decode it using UTF-8.

From cbb96bd57a2fa3fa5a0a11662ea4890a5ad9bc41 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Thu, 23 Sep 2021 07:43:33 -0400
Subject: [PATCH 31/35] one more docstring

---
 src/allmydata/test/test_openmetrics.py | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index a92098c88..385bf32a8 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -162,7 +162,20 @@ class OpenMetrics(SyncTestCase):
         self.assertThat(d, succeeded(matches_stats(self)))
 
 def matches_stats(testcase):
+    """
+    Create a matcher that matches a response that confirms to the OpenMetrics
+    specification.
 
+    * The ``Content-Type`` is **application/openmetrics-text; version=1.0.0; charset=utf-8**.
+    * The status is **OK**.
+    * The body can be parsed by an OpenMetrics parser.
+    * The metric families in the body are grouped and sorted.
+    * At least one of the expected families appears in the body.
+
+    :param testtools.TestCase testcase: The case to which to add detail about the matching process.
+
+    :return: A matcher.
+    """
     return MatchesAll(
         MatchesStructure(
             code=Equals(OK),

From f66a8ab1369f197163832a940c25efdb44f3dcde Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Thu, 23 Sep 2021 07:43:37 -0400
Subject: [PATCH 32/35] formatting and explicit unicode string literals

---
 src/allmydata/test/test_openmetrics.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 385bf32a8..d74958ffd 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -180,7 +180,10 @@ def matches_stats(testcase):
         MatchesStructure(
             code=Equals(OK),
             # "The content type MUST be..."
-            headers=has_header("content-type", "application/openmetrics-text; version=1.0.0; charset=utf-8"),
+            headers=has_header(
+                u"content-type",
+                u"application/openmetrics-text; version=1.0.0; charset=utf-8",
+            ),
         ),
         AfterPreprocessing(
             readBodyText,

From 4b6d00221e289a94fa9603dc0d1050605c0411ab Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Thu, 23 Sep 2021 07:48:19 -0400
Subject: [PATCH 33/35] protect this crazy line from black

---
 src/allmydata/test/test_openmetrics.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index d74958ffd..71433c11a 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -10,8 +10,11 @@ from __future__ import division
 from __future__ import unicode_literals
 
 from future.utils import PY2
+
 if PY2:
+    # fmt: off
     from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
+    # fmt: on
 
 from prometheus_client.openmetrics import parser
 

From 2f60ab300ba724bd67c0ca0825af089eecf13e36 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Thu, 23 Sep 2021 07:48:27 -0400
Subject: [PATCH 34/35] black formatting

---
 src/allmydata/test/test_openmetrics.py | 211 +++++++++++++------------
 1 file changed, 112 insertions(+), 99 deletions(-)

diff --git a/src/allmydata/test/test_openmetrics.py b/src/allmydata/test/test_openmetrics.py
index 71433c11a..66cbc7dec 100644
--- a/src/allmydata/test/test_openmetrics.py
+++ b/src/allmydata/test/test_openmetrics.py
@@ -31,7 +31,7 @@ from testtools.matchers import (
     MatchesAll,
     MatchesStructure,
     MatchesPredicate,
-    )
+)
 from testtools.content import text_content
 
 from allmydata.web.status import Statistics
@@ -43,99 +43,103 @@ class FakeStatsProvider(object):
     A stats provider that hands backed a canned collection of performance
     statistics.
     """
+
     def get_stats(self):
         # Parsed into a dict from a running tahoe's /statistics?t=json
         stats = {
-          'stats': {
-            'storage_server.latencies.get.99_9_percentile': None,
-            'storage_server.latencies.close.10_0_percentile': 0.00021910667419433594,
-            'storage_server.latencies.read.01_0_percentile': 2.8848648071289062e-05,
-            'storage_server.latencies.writev.99_9_percentile': None,
-            'storage_server.latencies.read.99_9_percentile': None,
-            'storage_server.latencies.allocate.99_0_percentile': 0.000988006591796875,
-            'storage_server.latencies.writev.mean': 0.00045332245070571654,
-            'storage_server.latencies.close.99_9_percentile': None,
-            'cpu_monitor.15min_avg': 0.00017592000079223033,
-            'storage_server.disk_free_for_root': 103289454592,
-            'storage_server.latencies.get.99_0_percentile': 0.000347137451171875,
-            'storage_server.latencies.get.mean': 0.00021158285060171353,
-            'storage_server.latencies.read.90_0_percentile': 8.893013000488281e-05,
-            'storage_server.latencies.write.01_0_percentile': 3.600120544433594e-05,
-            'storage_server.latencies.write.99_9_percentile': 0.00017690658569335938,
-            'storage_server.latencies.close.90_0_percentile': 0.00033211708068847656,
-            'storage_server.disk_total': 103497859072,
-            'storage_server.latencies.close.95_0_percentile': 0.0003509521484375,
-            'storage_server.latencies.readv.samplesize': 1000,
-            'storage_server.disk_free_for_nonroot': 103289454592,
-            'storage_server.latencies.close.mean': 0.0002715024480059103,
-            'storage_server.latencies.writev.95_0_percentile': 0.0007410049438476562,
-            'storage_server.latencies.readv.90_0_percentile': 0.0003781318664550781,
-            'storage_server.latencies.readv.99_0_percentile': 0.0004050731658935547,
-            'storage_server.latencies.allocate.mean': 0.0007128627429454784,
-            'storage_server.latencies.close.samplesize': 326,
-            'storage_server.latencies.get.50_0_percentile': 0.0001819133758544922,
-            'storage_server.latencies.write.50_0_percentile': 4.482269287109375e-05,
-            'storage_server.latencies.readv.01_0_percentile': 0.0002970695495605469,
-            'storage_server.latencies.get.10_0_percentile': 0.00015687942504882812,
-            'storage_server.latencies.allocate.90_0_percentile': 0.0008189678192138672,
-            'storage_server.latencies.get.samplesize': 472,
-            'storage_server.total_bucket_count': 393,
-            'storage_server.latencies.read.mean': 5.936201880959903e-05,
-            'storage_server.latencies.allocate.01_0_percentile': 0.0004208087921142578,
-            'storage_server.latencies.allocate.99_9_percentile': None,
-            'storage_server.latencies.readv.mean': 0.00034061360359191893,
-            'storage_server.disk_used': 208404480,
-            'storage_server.latencies.allocate.50_0_percentile': 0.0007410049438476562,
-            'storage_server.latencies.read.99_0_percentile': 0.00011992454528808594,
-            'node.uptime': 3805759.8545179367,
-            'storage_server.latencies.writev.10_0_percentile': 0.00035190582275390625,
-            'storage_server.latencies.writev.90_0_percentile': 0.0006821155548095703,
-            'storage_server.latencies.close.01_0_percentile': 0.00021505355834960938,
-            'storage_server.latencies.close.50_0_percentile': 0.0002579689025878906,
-            'cpu_monitor.1min_avg': 0.0002130000000003444,
-            'storage_server.latencies.writev.50_0_percentile': 0.0004138946533203125,
-            'storage_server.latencies.read.95_0_percentile': 9.107589721679688e-05,
-            'storage_server.latencies.readv.95_0_percentile': 0.0003859996795654297,
-            'storage_server.latencies.write.10_0_percentile': 3.719329833984375e-05,
-            'storage_server.accepting_immutable_shares': 1,
-            'storage_server.latencies.writev.samplesize': 309,
-            'storage_server.latencies.get.95_0_percentile': 0.0003190040588378906,
-            'storage_server.latencies.readv.10_0_percentile': 0.00032210350036621094,
-            'storage_server.latencies.get.90_0_percentile': 0.0002999305725097656,
-            'storage_server.latencies.get.01_0_percentile': 0.0001239776611328125,
-            'cpu_monitor.total': 641.4941180000001,
-            'storage_server.latencies.write.samplesize': 1000,
-            'storage_server.latencies.write.95_0_percentile': 9.489059448242188e-05,
-            'storage_server.latencies.read.50_0_percentile': 6.890296936035156e-05,
-            'storage_server.latencies.writev.01_0_percentile': 0.00033211708068847656,
-            'storage_server.latencies.read.10_0_percentile': 3.0994415283203125e-05,
-            'storage_server.latencies.allocate.10_0_percentile': 0.0004949569702148438,
-            'storage_server.reserved_space': 0,
-            'storage_server.disk_avail': 103289454592,
-            'storage_server.latencies.write.99_0_percentile': 0.00011301040649414062,
-            'storage_server.latencies.write.90_0_percentile': 9.083747863769531e-05,
-            'cpu_monitor.5min_avg': 0.0002370666691157502,
-            'storage_server.latencies.write.mean': 5.8008909225463864e-05,
-            'storage_server.latencies.readv.50_0_percentile': 0.00033020973205566406,
-            'storage_server.latencies.close.99_0_percentile': 0.0004038810729980469,
-            'storage_server.allocated': 0,
-            'storage_server.latencies.writev.99_0_percentile': 0.0007710456848144531,
-            'storage_server.latencies.readv.99_9_percentile': 0.0004780292510986328,
-            'storage_server.latencies.read.samplesize': 170,
-            'storage_server.latencies.allocate.samplesize': 406,
-            'storage_server.latencies.allocate.95_0_percentile': 0.0008411407470703125},
-          'counters': {
-            'storage_server.writev': 309,
-            'storage_server.bytes_added': 197836146,
-            'storage_server.close': 326,
-            'storage_server.readv': 14299,
-            'storage_server.allocate': 406,
-            'storage_server.read': 170,
-            'storage_server.write': 3775,
-            'storage_server.get': 472}
-          }
+            "stats": {
+                "storage_server.latencies.get.99_9_percentile": None,
+                "storage_server.latencies.close.10_0_percentile": 0.00021910667419433594,
+                "storage_server.latencies.read.01_0_percentile": 2.8848648071289062e-05,
+                "storage_server.latencies.writev.99_9_percentile": None,
+                "storage_server.latencies.read.99_9_percentile": None,
+                "storage_server.latencies.allocate.99_0_percentile": 0.000988006591796875,
+                "storage_server.latencies.writev.mean": 0.00045332245070571654,
+                "storage_server.latencies.close.99_9_percentile": None,
+                "cpu_monitor.15min_avg": 0.00017592000079223033,
+                "storage_server.disk_free_for_root": 103289454592,
+                "storage_server.latencies.get.99_0_percentile": 0.000347137451171875,
+                "storage_server.latencies.get.mean": 0.00021158285060171353,
+                "storage_server.latencies.read.90_0_percentile": 8.893013000488281e-05,
+                "storage_server.latencies.write.01_0_percentile": 3.600120544433594e-05,
+                "storage_server.latencies.write.99_9_percentile": 0.00017690658569335938,
+                "storage_server.latencies.close.90_0_percentile": 0.00033211708068847656,
+                "storage_server.disk_total": 103497859072,
+                "storage_server.latencies.close.95_0_percentile": 0.0003509521484375,
+                "storage_server.latencies.readv.samplesize": 1000,
+                "storage_server.disk_free_for_nonroot": 103289454592,
+                "storage_server.latencies.close.mean": 0.0002715024480059103,
+                "storage_server.latencies.writev.95_0_percentile": 0.0007410049438476562,
+                "storage_server.latencies.readv.90_0_percentile": 0.0003781318664550781,
+                "storage_server.latencies.readv.99_0_percentile": 0.0004050731658935547,
+                "storage_server.latencies.allocate.mean": 0.0007128627429454784,
+                "storage_server.latencies.close.samplesize": 326,
+                "storage_server.latencies.get.50_0_percentile": 0.0001819133758544922,
+                "storage_server.latencies.write.50_0_percentile": 4.482269287109375e-05,
+                "storage_server.latencies.readv.01_0_percentile": 0.0002970695495605469,
+                "storage_server.latencies.get.10_0_percentile": 0.00015687942504882812,
+                "storage_server.latencies.allocate.90_0_percentile": 0.0008189678192138672,
+                "storage_server.latencies.get.samplesize": 472,
+                "storage_server.total_bucket_count": 393,
+                "storage_server.latencies.read.mean": 5.936201880959903e-05,
+                "storage_server.latencies.allocate.01_0_percentile": 0.0004208087921142578,
+                "storage_server.latencies.allocate.99_9_percentile": None,
+                "storage_server.latencies.readv.mean": 0.00034061360359191893,
+                "storage_server.disk_used": 208404480,
+                "storage_server.latencies.allocate.50_0_percentile": 0.0007410049438476562,
+                "storage_server.latencies.read.99_0_percentile": 0.00011992454528808594,
+                "node.uptime": 3805759.8545179367,
+                "storage_server.latencies.writev.10_0_percentile": 0.00035190582275390625,
+                "storage_server.latencies.writev.90_0_percentile": 0.0006821155548095703,
+                "storage_server.latencies.close.01_0_percentile": 0.00021505355834960938,
+                "storage_server.latencies.close.50_0_percentile": 0.0002579689025878906,
+                "cpu_monitor.1min_avg": 0.0002130000000003444,
+                "storage_server.latencies.writev.50_0_percentile": 0.0004138946533203125,
+                "storage_server.latencies.read.95_0_percentile": 9.107589721679688e-05,
+                "storage_server.latencies.readv.95_0_percentile": 0.0003859996795654297,
+                "storage_server.latencies.write.10_0_percentile": 3.719329833984375e-05,
+                "storage_server.accepting_immutable_shares": 1,
+                "storage_server.latencies.writev.samplesize": 309,
+                "storage_server.latencies.get.95_0_percentile": 0.0003190040588378906,
+                "storage_server.latencies.readv.10_0_percentile": 0.00032210350036621094,
+                "storage_server.latencies.get.90_0_percentile": 0.0002999305725097656,
+                "storage_server.latencies.get.01_0_percentile": 0.0001239776611328125,
+                "cpu_monitor.total": 641.4941180000001,
+                "storage_server.latencies.write.samplesize": 1000,
+                "storage_server.latencies.write.95_0_percentile": 9.489059448242188e-05,
+                "storage_server.latencies.read.50_0_percentile": 6.890296936035156e-05,
+                "storage_server.latencies.writev.01_0_percentile": 0.00033211708068847656,
+                "storage_server.latencies.read.10_0_percentile": 3.0994415283203125e-05,
+                "storage_server.latencies.allocate.10_0_percentile": 0.0004949569702148438,
+                "storage_server.reserved_space": 0,
+                "storage_server.disk_avail": 103289454592,
+                "storage_server.latencies.write.99_0_percentile": 0.00011301040649414062,
+                "storage_server.latencies.write.90_0_percentile": 9.083747863769531e-05,
+                "cpu_monitor.5min_avg": 0.0002370666691157502,
+                "storage_server.latencies.write.mean": 5.8008909225463864e-05,
+                "storage_server.latencies.readv.50_0_percentile": 0.00033020973205566406,
+                "storage_server.latencies.close.99_0_percentile": 0.0004038810729980469,
+                "storage_server.allocated": 0,
+                "storage_server.latencies.writev.99_0_percentile": 0.0007710456848144531,
+                "storage_server.latencies.readv.99_9_percentile": 0.0004780292510986328,
+                "storage_server.latencies.read.samplesize": 170,
+                "storage_server.latencies.allocate.samplesize": 406,
+                "storage_server.latencies.allocate.95_0_percentile": 0.0008411407470703125,
+            },
+            "counters": {
+                "storage_server.writev": 309,
+                "storage_server.bytes_added": 197836146,
+                "storage_server.close": 326,
+                "storage_server.readv": 14299,
+                "storage_server.allocate": 406,
+                "storage_server.read": 170,
+                "storage_server.write": 3775,
+                "storage_server.get": 472,
+            },
+        }
         return stats
 
+
 class HackItResource(Resource, object):
     """
     A bridge between ``RequestTraversalAgent`` and ``MultiFormatResource``
@@ -143,6 +147,7 @@ class HackItResource(Resource, object):
     object to have a ``fields`` attribute but Twisted's ``IRequest`` has no
     such attribute.  Create it here.
     """
+
     def getChildWithDefault(self, path, request):
         request.fields = None
         return Resource.getChildWithDefault(self, path, request)
@@ -152,6 +157,7 @@ class OpenMetrics(SyncTestCase):
     """
     Tests for ``/statistics?t=openmetrics``.
     """
+
     def test_spec_compliance(self):
         """
         Does our output adhere to the `OpenMetrics <https://openmetrics.io/>` spec?
@@ -164,6 +170,7 @@ class OpenMetrics(SyncTestCase):
         d = rta.request(b"GET", b"http://localhost/?t=openmetrics")
         self.assertThat(d, succeeded(matches_stats(self)))
 
+
 def matches_stats(testcase):
     """
     Create a matcher that matches a response that confirms to the OpenMetrics
@@ -184,19 +191,22 @@ def matches_stats(testcase):
             code=Equals(OK),
             # "The content type MUST be..."
             headers=has_header(
-                u"content-type",
-                u"application/openmetrics-text; version=1.0.0; charset=utf-8",
+                "content-type",
+                "application/openmetrics-text; version=1.0.0; charset=utf-8",
             ),
         ),
         AfterPreprocessing(
             readBodyText,
-            succeeded(MatchesAll(
-                MatchesPredicate(add_detail(testcase, u"response body"), u"%s dummy"),
-                parses_as_openmetrics(),
-            ))
-        )
+            succeeded(
+                MatchesAll(
+                    MatchesPredicate(add_detail(testcase, "response body"), "%s dummy"),
+                    parses_as_openmetrics(),
+                )
+            ),
+        ),
     )
 
+
 def add_detail(testcase, name):
     """
     Create a matcher that always matches and as a side-effect adds the matched
@@ -206,11 +216,14 @@ def add_detail(testcase, name):
 
     :return: A matcher.
     """
+
     def predicate(value):
         testcase.addDetail(name, text_content(value))
         return True
+
     return predicate
 
+
 def readBodyText(response):
     """
     Read the response body and decode it using UTF-8.
@@ -224,6 +237,7 @@ def readBodyText(response):
     d.addCallback(lambda body: body.decode("utf-8"))
     return d
 
+
 def has_header(name, value):
     """
     Create a matcher that matches a response object that includes the given
@@ -239,6 +253,7 @@ def has_header(name, value):
         Equals([value]),
     )
 
+
 def parses_as_openmetrics():
     """
     Create a matcher that matches a ``str`` string that can be parsed as an
@@ -253,8 +268,6 @@ def parses_as_openmetrics():
         lambda body: list(parser.text_string_to_metric_families(body)),
         AfterPreprocessing(
             lambda families: families[-1].name,
-            Equals(u"tahoe_stats_storage_server_total_bucket_count"),
+            Equals("tahoe_stats_storage_server_total_bucket_count"),
         ),
     )
-
-

From 7183d53c23e3126032a59b5617259af240ead552 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Thu, 23 Sep 2021 07:58:02 -0400
Subject: [PATCH 35/35] put test dependency in the setuptools test extra

---
 setup.py | 2 ++
 tox.ini  | 2 --
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/setup.py b/setup.py
index 3433e93f4..27407a403 100644
--- a/setup.py
+++ b/setup.py
@@ -404,6 +404,8 @@ setup(name="tahoe-lafs", # also set in __init__.py
               "tenacity",
               "paramiko",
               "pytest-timeout",
+              # Does our OpenMetrics endpoint adhere to the spec:
+              "prometheus-client == 0.11.0",
           ] + tor_requires + i2p_requires,
           "tor": tor_requires,
           "i2p": i2p_requires,
diff --git a/tox.ini b/tox.ini
index 0e8e58ea6..9b0f71038 100644
--- a/tox.ini
+++ b/tox.ini
@@ -52,8 +52,6 @@ deps =
      certifi
      # VCS hooks support
      py36,!coverage: pre-commit
-     # Does our OpenMetrics endpoint adhere to the spec:
-     prometheus-client==0.11.0
 
 # We add usedevelop=False because testing against a true installation gives
 # more useful results.