Merge pull request #557 from tahoe-lafs/2980.eliot-destination-escaping

Fix escaping in Eliot destinations

Fixes: ticket:2980

src/allmydata/test/test_runner.py

@@ -186,6 +186,30 @@ class BinTahoe(common_util.SignalMixin, unittest.TestCase, RunBinTahoeMixin):
         ])
         self.assertEqual(rc_or_sig, 0)
 
+    @inlineCallbacks
+    def test_unknown_eliot_destination(self):
+        out, err, rc_or_sig = yield self.run_bintahoe([
+            "--eliot-destination=invalid:more",
+        ])
+        self.assertEqual(1, rc_or_sig)
+        self.assertIn("Unknown destination description", out)
+        self.assertIn("invalid:more", out)
+
+    @inlineCallbacks
+    def test_malformed_eliot_destination(self):
+        out, err, rc_or_sig = yield self.run_bintahoe([
+            "--eliot-destination=invalid",
+        ])
+        self.assertEqual(1, rc_or_sig)
+        self.assertIn("must be formatted like", out)
+
+    @inlineCallbacks
+    def test_escape_in_eliot_destination(self):
+        out, err, rc_or_sig = yield self.run_bintahoe([
+            "--eliot-destination=file:@foo",
+        ])
+        self.assertEqual(1, rc_or_sig)
+        self.assertIn("Unsupported escape character", out)
 
 
 class CreateNode(unittest.TestCase):

src/allmydata/util/eliotutil.py

@@ -65,6 +65,9 @@ from eliot._validation import (
     ValidationError,
 )
 
+from twisted.python.usage import (
+    UsageError,
+)
 from twisted.python.filepath import (
     FilePath,
 )
@@ -287,9 +290,12 @@ def opt_eliot_destination(self, description):
     """
     Add an Eliot logging destination.  May be given more than once.
     """
-    self.setdefault("destinations", []).append(
-        _parse_destination_description(description)
-    )
+    try:
+        destination = _parse_destination_description(description)
+    except Exception as e:
+        raise UsageError(str(e))
+    else:
+        self.setdefault("destinations", []).append(destination)
 
 
 def opt_help_eliot_destinations(self):
@@ -301,7 +307,7 @@ def opt_help_eliot_destinations(self):
         # Might want to generate this from some metadata someday but we just
         # have one hard-coded destination type now, it's easier to hard-code
         # the help.
-        "\tfile:<path>[:rotate_length=<bytes>][:max_rotated_files=<count>]\n"
+        "\tfile:<path>[,rotate_length=<bytes>][,max_rotated_files=<count>]\n"
         "\tSensible defaults are supplied for rotate_length and max_rotated_files\n"
         "\tif they are not given.\n",
         file=self.stdout,
@@ -399,7 +405,13 @@ class _DestinationParser(object):
     def parse(self, description):
         description = description.decode(u"ascii")
 
+        try:
             kind, args = description.split(u":", 1)
+        except ValueError:
+            raise ValueError(
+                u"Eliot destination description must be formatted like "
+                u"<kind>:<args>."
+            )
         try:
             parser = getattr(self, u"_parse_{}".format(kind))
         except AttributeError:
@@ -420,12 +432,17 @@ class _DestinationParser(object):
         )
 
     def _parse_file(self, kind, arg_text):
-        # Reserve the possibility of an escape character in the future.
-        if u"\\" in arg_text:
+        # Reserve the possibility of an escape character in the future.  \ is
+        # the standard choice but it's the path separator on Windows which
+        # pretty much ruins it in this context.  Most other symbols already
+        # have some shell-assigned meaning which makes them treacherous to use
+        # in a CLI interface.  Eliminating all such dangerous symbols leaves
+        # approximately @.
+        if u"@" in arg_text:
             raise ValueError(
-                u"Unsupported escape character (\\) in destination text ({!r}).".format(arg_text),
+                u"Unsupported escape character (@) in destination text ({!r}).".format(arg_text),
             )
-        arg_list = arg_text.split(u":")
+        arg_list = arg_text.split(u",")
         path_name = arg_list.pop(0)
         if path_name == "-":
             get_file = lambda: stdout

towncrier.pyproject.toml

@@ -46,3 +46,8 @@
         directory = "other"
         name = "Other Changes"
         showcontent = true
+
+    [[tool.towncrier.type]]
+        directory = "minor"
+        name = "Misc/Other"
+        showcontent = false