1 files changed, 111 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)