factor out yamlutil.py

The yaml.SafeLoader.add_constructor() should probably only be done once,
and moving this all into a module gives us an opportunity to test it
directly.

src/allmydata/client.py

@@ -1,4 +1,4 @@
-import os, stat, time, weakref, yaml
+import os, stat, time, weakref
 from allmydata import node
 from base64 import urlsafe_b64encode
 
@@ -17,9 +17,10 @@ from allmydata.immutable.upload import Uploader
 from allmydata.immutable.offloaded import Helper
 from allmydata.control import ControlServer
 from allmydata.introducer.client import IntroducerClient
-from allmydata.util import hashutil, base32, pollmixin, log, keyutil, idlib
-from allmydata.util.encodingutil import get_filesystem_encoding, \
-     from_utf8_or_none
+from allmydata.util import (hashutil, base32, pollmixin, log, keyutil, idlib,
+                            yamlutil)
+from allmydata.util.encodingutil import (get_filesystem_encoding,
+                                         from_utf8_or_none)
 from allmydata.util.fileutil import abspath_expanduser_unicode
 from allmydata.util.abbreviate import parse_abbreviated_size
 from allmydata.util.time_format import parse_duration, parse_date
@@ -189,17 +190,15 @@ class Client(node.Node, pollmixin.PollMixin):
         Load the connections.yaml file if it exists, otherwise
         create a default configuration.
         """
-        connections_filepath = FilePath(os.path.join(self.basedir, "private", "connections.yaml"))
-        def construct_unicode(loader, node):
-            return node.value
-        yaml.SafeLoader.add_constructor("tag:yaml.org,2002:str",
-                                        construct_unicode)
+        fn = os.path.join(self.basedir, "private", "connections.yaml")
+        connections_filepath = FilePath(fn)
         try:
             with connections_filepath.open() as f:
-                self.connections_config = yaml.safe_load(f)
+                self.connections_config = yamlutil.safe_load(f)
         except EnvironmentError:
             self.connections_config = { 'servers' : {} }
-            connections_filepath.setContent(yaml.safe_dump(self.connections_config))
+            content = yamlutil.safe_dump(self.connections_config)
+            connections_filepath.setContent(content)
 
     def init_stats_provider(self):
         gatherer_furl = self.get_config("client", "stats_gatherer.furl", None)

src/allmydata/introducer/client.py

@@ -1,5 +1,5 @@
 
-import time, yaml
+import time
 from zope.interface import implements
 from twisted.application import service
 from foolscap.api import Referenceable, eventually
@@ -8,7 +8,7 @@ from allmydata.introducer.interfaces import IIntroducerClient, \
      RIIntroducerSubscriberClient_v2
 from allmydata.introducer.common import sign_to_foolscap, unsign_from_foolscap,\
      get_tubid_string_from_ann
-from allmydata.util import log
+from allmydata.util import log, yamlutil
 from allmydata.util.rrefutil import add_version_to_remote_reference
 from allmydata.util.keyutil import BadSignatureError
 
@@ -89,15 +89,9 @@ class IntroducerClient(service.Service, Referenceable):
         d.addErrback(connect_failed)
 
     def _load_announcements(self):
-        # Announcements contain unicode, because they come from JSON. We tell
-        # PyYAML to give us unicode instead of str/bytes.
-        def construct_unicode(loader, node):
-            return node.value
-        yaml.SafeLoader.add_constructor("tag:yaml.org,2002:str",
-                                        construct_unicode)
         try:
             with self._cache_filepath.open() as f:
-                servers = yaml.safe_load(f)
+                servers = yamlutil.safe_load(f)
         except EnvironmentError:
             return # no cache file
         if not isinstance(servers, list):
@@ -121,7 +115,7 @@ class IntroducerClient(service.Service, Referenceable):
                 "key_s" : key_s,
                 }
             announcements.append(server_params)
-        announcement_cache_yaml = yaml.safe_dump(announcements)
+        announcement_cache_yaml = yamlutil.safe_dump(announcements)
         self._cache_filepath.setContent(announcement_cache_yaml)
 
     def _got_introducer(self, publisher):

src/allmydata/test/test_introducer.py

@@ -1,5 +1,5 @@
 
-import os, re, itertools, yaml
+import os, re, itertools
 from base64 import b32decode
 import simplejson
 
@@ -20,7 +20,7 @@ from allmydata.introducer.common import get_tubid_string_from_ann, \
 from allmydata.introducer import IntroducerNode
 from allmydata.web import introweb
 from allmydata.client import Client as TahoeClient
-from allmydata.util import pollmixin, keyutil, idlib, fileutil, iputil
+from allmydata.util import pollmixin, keyutil, idlib, fileutil, iputil, yamlutil
 import allmydata.test.common_util as testutil
 
 class LoggingMultiService(service.MultiService):
@@ -719,12 +719,8 @@ class Announcements(unittest.TestCase):
         self.failUnlessEqual(a[0].announcement["anonymous-storage-FURL"], furl1)
 
     def _load_cache(self, cache_filepath):
-        def construct_unicode(loader, node):
-            return node.value
-        yaml.SafeLoader.add_constructor("tag:yaml.org,2002:str",
-                                        construct_unicode)
         with cache_filepath.open() as f:
-            return yaml.safe_load(f)
+            return yamlutil.safe_load(f)
 
     @defer.inlineCallbacks
     def test_client_cache(self):
@@ -808,18 +804,6 @@ class Announcements(unittest.TestCase):
         self.failUnlessEqual(announcements[pub2]["anonymous-storage-FURL"],
                              furl3)
 
-class YAMLUnicode(unittest.TestCase):
-    def test_convert(self):
-        data = yaml.safe_dump(["str", u"unicode", u"\u1234nicode"])
-        def construct_unicode(loader, node):
-            return node.value
-        yaml.SafeLoader.add_constructor("tag:yaml.org,2002:str",
-                                        construct_unicode)
-        back = yaml.safe_load(data)
-        self.failUnlessEqual(type(back[0]), unicode)
-        self.failUnlessEqual(type(back[1]), unicode)
-        self.failUnlessEqual(type(back[2]), unicode)
-
 class ClientSeqnums(unittest.TestCase):
     def test_client(self):
         basedir = "introducer/ClientSeqnums/test_client"

src/allmydata/test/test_util.py

@@ -1,7 +1,7 @@
 
 def foo(): pass # keep the line number constant
 
-import os, time, sys
+import os, time, sys, yaml
 from StringIO import StringIO
 from datetime import timedelta
 from twisted.trial import unittest
@@ -13,7 +13,7 @@ from pycryptopp.hash.sha256 import SHA256 as _hash
 from allmydata.util import base32, idlib, humanreadable, mathutil, hashutil
 from allmydata.util import assertutil, fileutil, deferredutil, abbreviate
 from allmydata.util import limiter, time_format, pollmixin, cachedir
-from allmydata.util import statistics, dictutil, pipeline
+from allmydata.util import statistics, dictutil, pipeline, yamlutil
 from allmydata.util import log as tahoe_log
 from allmydata.util.spans import Spans, overlap, DataSpans
 from allmydata.test.common_util import ReallyEqualMixin, TimezoneMixin
@@ -2412,3 +2412,11 @@ class StringSpans(unittest.TestCase):
                 length = max(1, int(what[5:6], 16))
                 d1 = s1.get(start, length); d2 = s2.get(start, length)
                 self.failUnlessEqual(d1, d2, "%d+%d" % (start, length))
+
+class YAML(unittest.TestCase):
+    def test_convert(self):
+        data = yaml.safe_dump(["str", u"unicode", u"\u1234nicode"])
+        back = yamlutil.safe_load(data)
+        self.failUnlessEqual(type(back[0]), unicode)
+        self.failUnlessEqual(type(back[1]), unicode)
+        self.failUnlessEqual(type(back[2]), unicode)

src/allmydata/util/yamlutil.py

@@ -0,0 +1,14 @@
+import yaml
+
+# Announcements contain unicode, because they come from JSON. We tell PyYAML
+# to give us unicode instead of str/bytes.
+def construct_unicode(loader, node):
+    return node.value
+yaml.SafeLoader.add_constructor("tag:yaml.org,2002:str",
+                                construct_unicode)
+
+def safe_load(f):
+    return yaml.safe_load(f)
+
+def safe_dump(obj):
+    return yaml.safe_dump(obj)