Support generating structured logs in addition to standard logs. (#8607)

This modifies the configuration of structured logging to be usable from
the standard Python logging configuration.

This also separates the formatting of logs from the transport allowing
JSON logs to files or standard logs to sockets.

4 files changed, 257 insertions, 397 deletions

diff --git a/tests/logging/__init__.py b/tests/logging/__init__.py
index e69de29bb2..a58d51441c 100644
--- a/tests/logging/__init__.py
+++ b/tests/logging/__init__.py
@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+
+class LoggerCleanupMixin:
+    def get_logger(self, handler):
+        """
+        Attach a handler to a logger and add clean-ups to remove revert this.
+        """
+        # Create a logger and add the handler to it.
+        logger = logging.getLogger(__name__)
+        logger.addHandler(handler)
+
+        # Ensure the logger actually logs something.
+        logger.setLevel(logging.INFO)
+
+        # Ensure the logger gets cleaned-up appropriately.
+        self.addCleanup(logger.removeHandler, handler)
+        self.addCleanup(logger.setLevel, logging.NOTSET)
+
+        return logger
diff --git a/tests/logging/test_remote_handler.py b/tests/logging/test_remote_handler.py
new file mode 100644
index 0000000000..58ee1f2f3c
--- /dev/null
+++ b/tests/logging/test_remote_handler.py
@@ -0,0 +1,153 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from twisted.test.proto_helpers import AccumulatingProtocol
+
+from synapse.logging import RemoteHandler
+
+from tests.logging import LoggerCleanupMixin
+from tests.server import FakeTransport, get_clock
+from tests.unittest import TestCase
+
+
+def connect_logging_client(reactor, client_id):
+    # This is essentially tests.server.connect_client, but disabling autoflush on
+    # the client transport. This is necessary to avoid an infinite loop due to
+    # sending of data via the logging transport causing additional logs to be
+    # written.
+    factory = reactor.tcpClients.pop(client_id)[2]
+    client = factory.buildProtocol(None)
+    server = AccumulatingProtocol()
+    server.makeConnection(FakeTransport(client, reactor))
+    client.makeConnection(FakeTransport(server, reactor, autoflush=False))
+
+    return client, server
+
+
+class RemoteHandlerTestCase(LoggerCleanupMixin, TestCase):
+    def setUp(self):
+        self.reactor, _ = get_clock()
+
+    def test_log_output(self):
+        """
+        The remote handler delivers logs over TCP.
+        """
+        handler = RemoteHandler("127.0.0.1", 9000, _reactor=self.reactor)
+        logger = self.get_logger(handler)
+
+        logger.info("Hello there, %s!", "wally")
+
+        # Trigger the connection
+        client, server = connect_logging_client(self.reactor, 0)
+
+        # Trigger data being sent
+        client.transport.flush()
+
+        # One log message, with a single trailing newline
+        logs = server.data.decode("utf8").splitlines()
+        self.assertEqual(len(logs), 1)
+        self.assertEqual(server.data.count(b"\n"), 1)
+
+        # Ensure the data passed through properly.
+        self.assertEqual(logs[0], "Hello there, wally!")
+
+    def test_log_backpressure_debug(self):
+        """
+        When backpressure is hit, DEBUG logs will be shed.
+        """
+        handler = RemoteHandler(
+            "127.0.0.1", 9000, maximum_buffer=10, _reactor=self.reactor
+        )
+        logger = self.get_logger(handler)
+
+        # Send some debug messages
+        for i in range(0, 3):
+            logger.debug("debug %s" % (i,))
+
+        # Send a bunch of useful messages
+        for i in range(0, 7):
+            logger.info("info %s" % (i,))
+
+        # The last debug message pushes it past the maximum buffer
+        logger.debug("too much debug")
+
+        # Allow the reconnection
+        client, server = connect_logging_client(self.reactor, 0)
+        client.transport.flush()
+
+        # Only the 7 infos made it through, the debugs were elided
+        logs = server.data.splitlines()
+        self.assertEqual(len(logs), 7)
+        self.assertNotIn(b"debug", server.data)
+
+    def test_log_backpressure_info(self):
+        """
+        When backpressure is hit, DEBUG and INFO logs will be shed.
+        """
+        handler = RemoteHandler(
+            "127.0.0.1", 9000, maximum_buffer=10, _reactor=self.reactor
+        )
+        logger = self.get_logger(handler)
+
+        # Send some debug messages
+        for i in range(0, 3):
+            logger.debug("debug %s" % (i,))
+
+        # Send a bunch of useful messages
+        for i in range(0, 10):
+            logger.warning("warn %s" % (i,))
+
+        # Send a bunch of info messages
+        for i in range(0, 3):
+            logger.info("info %s" % (i,))
+
+        # The last debug message pushes it past the maximum buffer
+        logger.debug("too much debug")
+
+        # Allow the reconnection
+        client, server = connect_logging_client(self.reactor, 0)
+        client.transport.flush()
+
+        # The 10 warnings made it through, the debugs and infos were elided
+        logs = server.data.splitlines()
+        self.assertEqual(len(logs), 10)
+        self.assertNotIn(b"debug", server.data)
+        self.assertNotIn(b"info", server.data)
+
+    def test_log_backpressure_cut_middle(self):
+        """
+        When backpressure is hit, and no more DEBUG and INFOs cannot be culled,
+        it will cut the middle messages out.
+        """
+        handler = RemoteHandler(
+            "127.0.0.1", 9000, maximum_buffer=10, _reactor=self.reactor
+        )
+        logger = self.get_logger(handler)
+
+        # Send a bunch of useful messages
+        for i in range(0, 20):
+            logger.warning("warn %s" % (i,))
+
+        # Allow the reconnection
+        client, server = connect_logging_client(self.reactor, 0)
+        client.transport.flush()
+
+        # The first five and last five warnings made it through, the debugs and
+        # infos were elided
+        logs = server.data.decode("utf8").splitlines()
+        self.assertEqual(
+            ["warn %s" % (i,) for i in range(5)]
+            + ["warn %s" % (i,) for i in range(15, 20)],
+            logs,
+        )
diff --git a/tests/logging/test_structured.py b/tests/logging/test_structured.py
deleted file mode 100644
index d36f5f426c..0000000000
--- a/tests/logging/test_structured.py
+++ /dev/null
@@ -1,214 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2019 The Matrix.org Foundation C.I.C.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-import logging
-import os
-import os.path
-import shutil
-import sys
-import textwrap
-
-from twisted.logger import Logger, eventAsText, eventsFromJSONLogFile
-
-from synapse.config.logger import setup_logging
-from synapse.logging._structured import setup_structured_logging
-from synapse.logging.context import LoggingContext
-
-from tests.unittest import DEBUG, HomeserverTestCase
-
-
-class FakeBeginner:
-    def beginLoggingTo(self, observers, **kwargs):
-        self.observers = observers
-
-
-class StructuredLoggingTestBase:
-    """
-    Test base that registers a cleanup handler to reset the stdlib log handler
-    to 'unset'.
-    """
-
-    def prepare(self, reactor, clock, hs):
-        def _cleanup():
-            logging.getLogger("synapse").setLevel(logging.NOTSET)
-
-        self.addCleanup(_cleanup)
-
-
-class StructuredLoggingTestCase(StructuredLoggingTestBase, HomeserverTestCase):
-    """
-    Tests for Synapse's structured logging support.
-    """
-
-    def test_output_to_json_round_trip(self):
-        """
-        Synapse logs can be outputted to JSON and then read back again.
-        """
-        temp_dir = self.mktemp()
-        os.mkdir(temp_dir)
-        self.addCleanup(shutil.rmtree, temp_dir)
-
-        json_log_file = os.path.abspath(os.path.join(temp_dir, "out.json"))
-
-        log_config = {
-            "drains": {"jsonfile": {"type": "file_json", "location": json_log_file}}
-        }
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs, self.hs.config, log_config, logBeginner=beginner
-        )
-
-        # Make a logger and send an event
-        logger = Logger(
-            namespace="tests.logging.test_structured", observer=beginner.observers[0]
-        )
-        logger.info("Hello there, {name}!", name="wally")
-
-        # Read the log file and check it has the event we sent
-        with open(json_log_file, "r") as f:
-            logged_events = list(eventsFromJSONLogFile(f))
-        self.assertEqual(len(logged_events), 1)
-
-        # The event pulled from the file should render fine
-        self.assertEqual(
-            eventAsText(logged_events[0], includeTimestamp=False),
-            "[tests.logging.test_structured#info] Hello there, wally!",
-        )
-
-    def test_output_to_text(self):
-        """
-        Synapse logs can be outputted to text.
-        """
-        temp_dir = self.mktemp()
-        os.mkdir(temp_dir)
-        self.addCleanup(shutil.rmtree, temp_dir)
-
-        log_file = os.path.abspath(os.path.join(temp_dir, "out.log"))
-
-        log_config = {"drains": {"file": {"type": "file", "location": log_file}}}
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs, self.hs.config, log_config, logBeginner=beginner
-        )
-
-        # Make a logger and send an event
-        logger = Logger(
-            namespace="tests.logging.test_structured", observer=beginner.observers[0]
-        )
-        logger.info("Hello there, {name}!", name="wally")
-
-        # Read the log file and check it has the event we sent
-        with open(log_file, "r") as f:
-            logged_events = f.read().strip().split("\n")
-        self.assertEqual(len(logged_events), 1)
-
-        # The event pulled from the file should render fine
-        self.assertTrue(
-            logged_events[0].endswith(
-                " - tests.logging.test_structured - INFO - None - Hello there, wally!"
-            )
-        )
-
-    def test_collects_logcontext(self):
-        """
-        Test that log outputs have the attached logging context.
-        """
-        log_config = {"drains": {}}
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        publisher = setup_structured_logging(
-            self.hs, self.hs.config, log_config, logBeginner=beginner
-        )
-
-        logs = []
-
-        publisher.addObserver(logs.append)
-
-        # Make a logger and send an event
-        logger = Logger(
-            namespace="tests.logging.test_structured", observer=beginner.observers[0]
-        )
-
-        with LoggingContext("testcontext", request="somereq"):
-            logger.info("Hello there, {name}!", name="steve")
-
-        self.assertEqual(len(logs), 1)
-        self.assertEqual(logs[0]["request"], "somereq")
-
-
-class StructuredLoggingConfigurationFileTestCase(
-    StructuredLoggingTestBase, HomeserverTestCase
-):
-    def make_homeserver(self, reactor, clock):
-
-        tempdir = self.mktemp()
-        os.mkdir(tempdir)
-        log_config_file = os.path.abspath(os.path.join(tempdir, "log.config.yaml"))
-        self.homeserver_log = os.path.abspath(os.path.join(tempdir, "homeserver.log"))
-
-        config = self.default_config()
-        config["log_config"] = log_config_file
-
-        with open(log_config_file, "w") as f:
-            f.write(
-                textwrap.dedent(
-                    """\
-                    structured: true
-
-                    drains:
-                        file:
-                            type: file_json
-                            location: %s
-                    """
-                    % (self.homeserver_log,)
-                )
-            )
-
-        self.addCleanup(self._sys_cleanup)
-
-        return self.setup_test_homeserver(config=config)
-
-    def _sys_cleanup(self):
-        sys.stdout = sys.__stdout__
-        sys.stderr = sys.__stderr__
-
-    # Do not remove! We need the logging system to be set other than WARNING.
-    @DEBUG
-    def test_log_output(self):
-        """
-        When a structured logging config is given, Synapse will use it.
-        """
-        beginner = FakeBeginner()
-        publisher = setup_logging(self.hs, self.hs.config, logBeginner=beginner)
-
-        # Make a logger and send an event
-        logger = Logger(namespace="tests.logging.test_structured", observer=publisher)
-
-        with LoggingContext("testcontext", request="somereq"):
-            logger.info("Hello there, {name}!", name="steve")
-
-        with open(self.homeserver_log, "r") as f:
-            logged_events = [
-                eventAsText(x, includeTimestamp=False) for x in eventsFromJSONLogFile(f)
-            ]
-
-        logs = "\n".join(logged_events)
-        self.assertTrue("***** STARTING SERVER *****" in logs)
-        self.assertTrue("Hello there, steve!" in logs)
diff --git a/tests/logging/test_terse_json.py b/tests/logging/test_terse_json.py
index fd128b88e0..73f469b802 100644
--- a/tests/logging/test_terse_json.py
+++ b/tests/logging/test_terse_json.py
@@ -14,57 +14,33 @@
 # limitations under the License.
 
 import json
-from collections import Counter
+import logging
+from io import StringIO
 
-from twisted.logger import Logger
+from synapse.logging._terse_json import JsonFormatter, TerseJsonFormatter
 
-from synapse.logging._structured import setup_structured_logging
+from tests.logging import LoggerCleanupMixin
+from tests.unittest import TestCase
 
-from tests.server import connect_client
-from tests.unittest import HomeserverTestCase
 
-from .test_structured import FakeBeginner, StructuredLoggingTestBase
-
-
-class TerseJSONTCPTestCase(StructuredLoggingTestBase, HomeserverTestCase):
-    def test_log_output(self):
+class TerseJsonTestCase(LoggerCleanupMixin, TestCase):
+    def test_terse_json_output(self):
         """
-        The Terse JSON outputter delivers simplified structured logs over TCP.
+        The Terse JSON formatter converts log messages to JSON.
         """
-        log_config = {
-            "drains": {
-                "tersejson": {
-                    "type": "network_json_terse",
-                    "host": "127.0.0.1",
-                    "port": 8000,
-                }
-            }
-        }
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs, self.hs.config, log_config, logBeginner=beginner
-        )
-
-        logger = Logger(
-            namespace="tests.logging.test_terse_json", observer=beginner.observers[0]
-        )
-        logger.info("Hello there, {name}!", name="wally")
-
-        # Trigger the connection
-        self.pump()
+        output = StringIO()
 
-        _, server = connect_client(self.reactor, 0)
+        handler = logging.StreamHandler(output)
+        handler.setFormatter(TerseJsonFormatter())
+        logger = self.get_logger(handler)
 
-        # Trigger data being sent
-        self.pump()
+        logger.info("Hello there, %s!", "wally")
 
-        # One log message, with a single trailing newline
-        logs = server.data.decode("utf8").splitlines()
+        # One log message, with a single trailing newline.
+        data = output.getvalue()
+        logs = data.splitlines()
         self.assertEqual(len(logs), 1)
-        self.assertEqual(server.data.count(b"\n"), 1)
-
+        self.assertEqual(data.count("\n"), 1)
         log = json.loads(logs[0])
 
         # The terse logger should give us these keys.
@@ -72,163 +48,74 @@ class TerseJSONTCPTestCase(StructuredLoggingTestBase, HomeserverTestCase):
             "log",
             "time",
             "level",
-            "log_namespace",
-            "request",
-            "scope",
-            "server_name",
-            "name",
+            "namespace",
         ]
         self.assertCountEqual(log.keys(), expected_log_keys)
+        self.assertEqual(log["log"], "Hello there, wally!")
 
-        # It contains the data we expect.
-        self.assertEqual(log["name"], "wally")
-
-    def test_log_backpressure_debug(self):
+    def test_extra_data(self):
         """
-        When backpressure is hit, DEBUG logs will be shed.
+        Additional information can be included in the structured logging.
         """
-        log_config = {
-            "loggers": {"synapse": {"level": "DEBUG"}},
-            "drains": {
-                "tersejson": {
-                    "type": "network_json_terse",
-                    "host": "127.0.0.1",
-                    "port": 8000,
-                    "maximum_buffer": 10,
-                }
-            },
-        }
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs,
-            self.hs.config,
-            log_config,
-            logBeginner=beginner,
-            redirect_stdlib_logging=False,
-        )
-
-        logger = Logger(
-            namespace="synapse.logging.test_terse_json", observer=beginner.observers[0]
-        )
+        output = StringIO()
 
-        # Send some debug messages
-        for i in range(0, 3):
-            logger.debug("debug %s" % (i,))
+        handler = logging.StreamHandler(output)
+        handler.setFormatter(TerseJsonFormatter())
+        logger = self.get_logger(handler)
 
-        # Send a bunch of useful messages
-        for i in range(0, 7):
-            logger.info("test message %s" % (i,))
-
-        # The last debug message pushes it past the maximum buffer
-        logger.debug("too much debug")
-
-        # Allow the reconnection
-        _, server = connect_client(self.reactor, 0)
-        self.pump()
-
-        # Only the 7 infos made it through, the debugs were elided
-        logs = server.data.splitlines()
-        self.assertEqual(len(logs), 7)
-
-    def test_log_backpressure_info(self):
-        """
-        When backpressure is hit, DEBUG and INFO logs will be shed.
-        """
-        log_config = {
-            "loggers": {"synapse": {"level": "DEBUG"}},
-            "drains": {
-                "tersejson": {
-                    "type": "network_json_terse",
-                    "host": "127.0.0.1",
-                    "port": 8000,
-                    "maximum_buffer": 10,
-                }
-            },
-        }
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs,
-            self.hs.config,
-            log_config,
-            logBeginner=beginner,
-            redirect_stdlib_logging=False,
-        )
-
-        logger = Logger(
-            namespace="synapse.logging.test_terse_json", observer=beginner.observers[0]
+        logger.info(
+            "Hello there, %s!", "wally", extra={"foo": "bar", "int": 3, "bool": True}
         )
 
-        # Send some debug messages
-        for i in range(0, 3):
-            logger.debug("debug %s" % (i,))
-
-        # Send a bunch of useful messages
-        for i in range(0, 10):
-            logger.warn("test warn %s" % (i,))
-
-        # Send a bunch of info messages
-        for i in range(0, 3):
-            logger.info("test message %s" % (i,))
-
-        # The last debug message pushes it past the maximum buffer
-        logger.debug("too much debug")
-
-        # Allow the reconnection
-        client, server = connect_client(self.reactor, 0)
-        self.pump()
+        # One log message, with a single trailing newline.
+        data = output.getvalue()
+        logs = data.splitlines()
+        self.assertEqual(len(logs), 1)
+        self.assertEqual(data.count("\n"), 1)
+        log = json.loads(logs[0])
 
-        # The 10 warnings made it through, the debugs and infos were elided
-        logs = list(map(json.loads, server.data.decode("utf8").splitlines()))
-        self.assertEqual(len(logs), 10)
+        # The terse logger should give us these keys.
+        expected_log_keys = [
+            "log",
+            "time",
+            "level",
+            "namespace",
+            # The additional keys given via extra.
+            "foo",
+            "int",
+            "bool",
+        ]
+        self.assertCountEqual(log.keys(), expected_log_keys)
 
-        self.assertEqual(Counter([x["level"] for x in logs]), {"WARN": 10})
+        # Check the values of the extra fields.
+        self.assertEqual(log["foo"], "bar")
+        self.assertEqual(log["int"], 3)
+        self.assertIs(log["bool"], True)
 
-    def test_log_backpressure_cut_middle(self):
+    def test_json_output(self):
         """
-        When backpressure is hit, and no more DEBUG and INFOs cannot be culled,
-        it will cut the middle messages out.
+        The Terse JSON formatter converts log messages to JSON.
         """
-        log_config = {
-            "loggers": {"synapse": {"level": "DEBUG"}},
-            "drains": {
-                "tersejson": {
-                    "type": "network_json_terse",
-                    "host": "127.0.0.1",
-                    "port": 8000,
-                    "maximum_buffer": 10,
-                }
-            },
-        }
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs,
-            self.hs.config,
-            log_config,
-            logBeginner=beginner,
-            redirect_stdlib_logging=False,
-        )
+        output = StringIO()
 
-        logger = Logger(
-            namespace="synapse.logging.test_terse_json", observer=beginner.observers[0]
-        )
+        handler = logging.StreamHandler(output)
+        handler.setFormatter(JsonFormatter())
+        logger = self.get_logger(handler)
 
-        # Send a bunch of useful messages
-        for i in range(0, 20):
-            logger.warn("test warn", num=i)
+        logger.info("Hello there, %s!", "wally")
 
-        # Allow the reconnection
-        client, server = connect_client(self.reactor, 0)
-        self.pump()
+        # One log message, with a single trailing newline.
+        data = output.getvalue()
+        logs = data.splitlines()
+        self.assertEqual(len(logs), 1)
+        self.assertEqual(data.count("\n"), 1)
+        log = json.loads(logs[0])
 
-        # The first five and last five warnings made it through, the debugs and
-        # infos were elided
-        logs = list(map(json.loads, server.data.decode("utf8").splitlines()))
-        self.assertEqual(len(logs), 10)
-        self.assertEqual(Counter([x["level"] for x in logs]), {"WARN": 10})
-        self.assertEqual([0, 1, 2, 3, 4, 15, 16, 17, 18, 19], [x["num"] for x in logs])
+        # The terse logger should give us these keys.
+        expected_log_keys = [
+            "log",
+            "level",
+            "namespace",
+        ]
+        self.assertCountEqual(log.keys(), expected_log_keys)
+        self.assertEqual(log["log"], "Hello there, wally!")