Merge branch 'release-v0.8.1' of github.com:matrix-org/synapse v0.8.1

3 files changed, 305 insertions, 0 deletions

diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
new file mode 100644
index 0000000000..dffb8a4861
--- /dev/null
+++ b/synapse/metrics/__init__.py
@@ -0,0 +1,111 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# 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.
+
+# Because otherwise 'resource' collides with synapse.metrics.resource
+from __future__ import absolute_import
+
+import logging
+from resource import getrusage, getpagesize, RUSAGE_SELF
+
+from .metric import (
+    CounterMetric, CallbackMetric, DistributionMetric, CacheMetric
+)
+
+
+logger = logging.getLogger(__name__)
+
+
+# We'll keep all the available metrics in a single toplevel dict, one shared
+# for the entire process. We don't currently support per-HomeServer instances
+# of metrics, because in practice any one python VM will host only one
+# HomeServer anyway. This makes a lot of implementation neater
+all_metrics = {}
+
+
+class Metrics(object):
+    """ A single Metrics object gives a (mutable) slice view of the all_metrics
+    dict, allowing callers to easily register new metrics that are namespaced
+    nicely."""
+
+    def __init__(self, name):
+        self.name_prefix = name
+
+    def _register(self, metric_class, name, *args, **kwargs):
+        full_name = "%s_%s" % (self.name_prefix, name)
+
+        metric = metric_class(full_name, *args, **kwargs)
+
+        all_metrics[full_name] = metric
+        return metric
+
+    def register_counter(self, *args, **kwargs):
+        return self._register(CounterMetric, *args, **kwargs)
+
+    def register_callback(self, *args, **kwargs):
+        return self._register(CallbackMetric, *args, **kwargs)
+
+    def register_distribution(self, *args, **kwargs):
+        return self._register(DistributionMetric, *args, **kwargs)
+
+    def register_cache(self, *args, **kwargs):
+        return self._register(CacheMetric, *args, **kwargs)
+
+
+def get_metrics_for(pkg_name):
+    """ Returns a Metrics instance for conveniently creating metrics
+    namespaced with the given name prefix. """
+
+    # Convert a "package.name" to "package_name" because Prometheus doesn't
+    # let us use . in metric names
+    return Metrics(pkg_name.replace(".", "_"))
+
+
+def render_all():
+    strs = []
+
+    # TODO(paul): Internal hack
+    update_resource_metrics()
+
+    for name in sorted(all_metrics.keys()):
+        try:
+            strs += all_metrics[name].render()
+        except Exception:
+            strs += ["# FAILED to render %s" % name]
+            logger.exception("Failed to render %s metric", name)
+
+    strs.append("")  # to generate a final CRLF
+
+    return "\n".join(strs)
+
+
+# Now register some standard process-wide state metrics, to give indications of
+# process resource usage
+
+rusage = None
+PAGE_SIZE = getpagesize()
+
+
+def update_resource_metrics():
+    global rusage
+    rusage = getrusage(RUSAGE_SELF)
+
+resource_metrics = get_metrics_for("process.resource")
+
+# msecs
+resource_metrics.register_callback("utime", lambda: rusage.ru_utime * 1000)
+resource_metrics.register_callback("stime", lambda: rusage.ru_stime * 1000)
+
+# pages
+resource_metrics.register_callback("maxrss", lambda: rusage.ru_maxrss * PAGE_SIZE)
diff --git a/synapse/metrics/metric.py b/synapse/metrics/metric.py
new file mode 100644
index 0000000000..21b37748f6
--- /dev/null
+++ b/synapse/metrics/metric.py
@@ -0,0 +1,155 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# 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 itertools import chain
+
+
+# TODO(paul): I can't believe Python doesn't have one of these
+def map_concat(func, items):
+    # flatten a list-of-lists
+    return list(chain.from_iterable(map(func, items)))
+
+
+class BaseMetric(object):
+
+    def __init__(self, name, labels=[]):
+        self.name = name
+        self.labels = labels  # OK not to clone as we never write it
+
+    def dimension(self):
+        return len(self.labels)
+
+    def is_scalar(self):
+        return not len(self.labels)
+
+    def _render_labelvalue(self, value):
+        # TODO: some kind of value escape
+        return '"%s"' % (value)
+
+    def _render_key(self, values):
+        if self.is_scalar():
+            return ""
+        return "{%s}" % (
+            ",".join(["%s=%s" % (k, self._render_labelvalue(v))
+                      for k, v in zip(self.labels, values)])
+        )
+
+    def render(self):
+        return map_concat(self.render_item, sorted(self.counts.keys()))
+
+
+class CounterMetric(BaseMetric):
+    """The simplest kind of metric; one that stores a monotonically-increasing
+    integer that counts events."""
+
+    def __init__(self, *args, **kwargs):
+        super(CounterMetric, self).__init__(*args, **kwargs)
+
+        self.counts = {}
+
+        # Scalar metrics are never empty
+        if self.is_scalar():
+            self.counts[()] = 0
+
+    def inc_by(self, incr, *values):
+        if len(values) != self.dimension():
+            raise ValueError(
+                "Expected as many values to inc() as labels (%d)" % (self.dimension())
+            )
+
+        # TODO: should assert that the tag values are all strings
+
+        if values not in self.counts:
+            self.counts[values] = incr
+        else:
+            self.counts[values] += incr
+
+    def inc(self, *values):
+        self.inc_by(1, *values)
+
+    def render_item(self, k):
+        return ["%s%s %d" % (self.name, self._render_key(k), self.counts[k])]
+
+
+class CallbackMetric(BaseMetric):
+    """A metric that returns the numeric value returned by a callback whenever
+    it is rendered. Typically this is used to implement gauges that yield the
+    size or other state of some in-memory object by actively querying it."""
+
+    def __init__(self, name, callback, labels=[]):
+        super(CallbackMetric, self).__init__(name, labels=labels)
+
+        self.callback = callback
+
+    def render(self):
+        value = self.callback()
+
+        if self.is_scalar():
+            return ["%s %d" % (self.name, value)]
+
+        return ["%s%s %d" % (self.name, self._render_key(k), value[k])
+                for k in sorted(value.keys())]
+
+
+class DistributionMetric(object):
+    """A combination of an event counter and an accumulator, which counts
+    both the number of events and accumulates the total value. Typically this
+    could be used to keep track of method-running times, or other distributions
+    of values that occur in discrete occurances.
+
+    TODO(paul): Try to export some heatmap-style stats?
+    """
+
+    def __init__(self, name, *args, **kwargs):
+        self.counts = CounterMetric(name + ":count", **kwargs)
+        self.totals = CounterMetric(name + ":total", **kwargs)
+
+    def inc_by(self, inc, *values):
+        self.counts.inc(*values)
+        self.totals.inc_by(inc, *values)
+
+    def render(self):
+        return self.counts.render() + self.totals.render()
+
+
+class CacheMetric(object):
+    """A combination of two CounterMetrics, one to count cache hits and one to
+    count a total, and a callback metric to yield the current size.
+
+    This metric generates standard metric name pairs, so that monitoring rules
+    can easily be applied to measure hit ratio."""
+
+    def __init__(self, name, size_callback, labels=[]):
+        self.name = name
+
+        self.hits = CounterMetric(name + ":hits", labels=labels)
+        self.total = CounterMetric(name + ":total", labels=labels)
+
+        self.size = CallbackMetric(
+            name + ":size",
+            callback=size_callback,
+            labels=labels,
+        )
+
+    def inc_hits(self, *values):
+        self.hits.inc(*values)
+        self.total.inc(*values)
+
+    def inc_misses(self, *values):
+        self.total.inc(*values)
+
+    def render(self):
+        return self.hits.render() + self.total.render() + self.size.render()
diff --git a/synapse/metrics/resource.py b/synapse/metrics/resource.py
new file mode 100644
index 0000000000..0af4b3eb52
--- /dev/null
+++ b/synapse/metrics/resource.py
@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# 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.web.resource import Resource
+
+import synapse.metrics
+
+
+METRICS_PREFIX = "/_synapse/metrics"
+
+
+class MetricsResource(Resource):
+    isLeaf = True
+
+    def __init__(self, hs):
+        Resource.__init__(self)  # Resource is old-style, so no super()
+
+        self.hs = hs
+
+    def render_GET(self, request):
+        response = synapse.metrics.render_all()
+
+        request.setHeader("Content-Type", "text/plain")
+        request.setHeader("Content-Length", str(len(response)))
+
+        # Encode as UTF-8 (default)
+        return response.encode()