Merge pull request #3256 from matrix-org/3218-official-prom

Switch to the Python Prometheus library

1 files changed, 119 insertions, 114 deletions

diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index e3b831db67..371c300cac 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -17,165 +17,170 @@ import logging
 import functools
 import time
 import gc
+import os
 import platform
+import attr
 
-from twisted.internet import reactor
+from prometheus_client import Gauge, Histogram, Counter
+from prometheus_client.core import GaugeMetricFamily, REGISTRY
 
-from .metric import (
-    CounterMetric, CallbackMetric, DistributionMetric, CacheMetric,
-    MemoryUsageMetric, GaugeMetric,
-)
-from .process_collector import register_process_collector
+from twisted.internet import reactor
 
 
 logger = logging.getLogger(__name__)
 
-
-running_on_pypy = platform.python_implementation() == 'PyPy'
+running_on_pypy = platform.python_implementation() == "PyPy"
 all_metrics = []
 all_collectors = []
+all_gauges = {}
 
 
-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."""
+class RegistryProxy(object):
 
-    def __init__(self, name):
-        self.name_prefix = name
+    def collect(self):
+        for metric in REGISTRY.collect():
+            if not metric.name.startswith("__"):
+                yield metric
 
-    def make_subspace(self, name):
-        return Metrics("%s_%s" % (self.name_prefix, name))
 
-    def register_collector(self, func):
-        all_collectors.append(func)
+@attr.s(hash=True)
+class LaterGauge(object):
 
-    def _register(self, metric_class, name, *args, **kwargs):
-        full_name = "%s_%s" % (self.name_prefix, name)
+    name = attr.ib()
+    desc = attr.ib()
+    labels = attr.ib(hash=False)
+    caller = attr.ib()
 
-        metric = metric_class(full_name, *args, **kwargs)
+    def collect(self):
 
-        all_metrics.append(metric)
-        return metric
+        g = GaugeMetricFamily(self.name, self.desc, labels=self.labels)
 
-    def register_counter(self, *args, **kwargs):
-        """
-        Returns:
-            CounterMetric
-        """
-        return self._register(CounterMetric, *args, **kwargs)
+        try:
+            calls = self.caller()
+        except Exception as e:
+            print(e)
+            logger.err()
+            yield g
 
-    def register_gauge(self, *args, **kwargs):
-        """
-        Returns:
-            GaugeMetric
-        """
-        return self._register(GaugeMetric, *args, **kwargs)
+        if isinstance(calls, dict):
+            for k, v in calls.items():
+                g.add_metric(k, v)
+        else:
+            g.add_metric([], calls)
 
-    def register_callback(self, *args, **kwargs):
-        """
-        Returns:
-            CallbackMetric
-        """
-        return self._register(CallbackMetric, *args, **kwargs)
+        yield g
 
-    def register_distribution(self, *args, **kwargs):
-        """
-        Returns:
-            DistributionMetric
-        """
-        return self._register(DistributionMetric, *args, **kwargs)
+    def __attrs_post_init__(self):
+        self._register()
 
-    def register_cache(self, *args, **kwargs):
-        """
-        Returns:
-            CacheMetric
-        """
-        return self._register(CacheMetric, *args, **kwargs)
+    def _register(self):
+        if self.name in all_gauges.keys():
+            logger.warning("%s already registered, reregistering" % (self.name,))
+            REGISTRY.unregister(all_gauges.pop(self.name))
 
+        REGISTRY.register(self)
+        all_gauges[self.name] = self
 
-def register_memory_metrics(hs):
-    try:
-        import psutil
-        process = psutil.Process()
-        process.memory_info().rss
-    except (ImportError, AttributeError):
-        logger.warn(
-            "psutil is not installed or incorrect version."
-            " Disabling memory metrics."
-        )
-        return
-    metric = MemoryUsageMetric(hs, psutil)
-    all_metrics.append(metric)
 
+#
+# Detailed CPU metrics
+#
 
-def get_metrics_for(pkg_name):
-    """ Returns a Metrics instance for conveniently creating metrics
-    namespaced with the given name prefix. """
+class CPUMetrics(object):
 
-    # Convert a "package.name" to "package_name" because Prometheus doesn't
-    # let us use . in metric names
-    return Metrics(pkg_name.replace(".", "_"))
+    def __init__(self):
+        ticks_per_sec = 100
+        try:
+            # Try and get the system config
+            ticks_per_sec = os.sysconf('SC_CLK_TCK')
+        except (ValueError, TypeError, AttributeError):
+            pass
 
+        self.ticks_per_sec = ticks_per_sec
 
-def render_all():
-    strs = []
+    def collect(self):
 
-    for collector in all_collectors:
-        collector()
+        with open("/proc/self/stat") as s:
+            line = s.read()
+            raw_stats = line.split(") ", 1)[1].split(" ")
 
-    for metric in all_metrics:
-        try:
-            strs += metric.render()
-        except Exception:
-            strs += ["# FAILED to render"]
-            logger.exception("Failed to render metric")
+            user = GaugeMetricFamily("process_cpu_user_seconds_total", "")
+            user.add_metric([], float(raw_stats[11]) / self.ticks_per_sec)
+            yield user
+
+            sys = GaugeMetricFamily("process_cpu_system_seconds_total", "")
+            sys.add_metric([], float(raw_stats[12]) / self.ticks_per_sec)
+            yield sys
 
-    strs.append("")  # to generate a final CRLF
 
-    return "\n".join(strs)
+REGISTRY.register(CPUMetrics())
+
+#
+# Python GC metrics
+#
+
+gc_unreachable = Gauge("python_gc_unreachable_total", "Unreachable GC objects", ["gen"])
+gc_time = Histogram(
+    "python_gc_time",
+    "Time taken to GC (sec)",
+    ["gen"],
+    buckets=[0.0025, 0.005, 0.01, 0.025, 0.05, 0.10, 0.25, 0.50, 1.00, 2.50,
+             5.00, 7.50, 15.00, 30.00, 45.00, 60.00],
+)
 
 
-register_process_collector(get_metrics_for("process"))
+class GCCounts(object):
 
+    def collect(self):
+        cm = GaugeMetricFamily("python_gc_counts", "GC cycle counts", labels=["gen"])
+        for n, m in enumerate(gc.get_count()):
+            cm.add_metric([str(n)], m)
 
-python_metrics = get_metrics_for("python")
+        yield cm
 
-gc_time = python_metrics.register_distribution("gc_time", labels=["gen"])
-gc_unreachable = python_metrics.register_counter("gc_unreachable_total", labels=["gen"])
-python_metrics.register_callback(
-    "gc_counts", lambda: {(i,): v for i, v in enumerate(gc.get_count())}, labels=["gen"]
+
+REGISTRY.register(GCCounts())
+
+#
+# Twisted reactor metrics
+#
+
+tick_time = Histogram(
+    "python_twisted_reactor_tick_time",
+    "Tick time of the Twisted reactor (sec)",
+    buckets=[0.001, 0.002, 0.005, 0.01, 0.025, 0.05, 0.1, 0.2, 0.5, 1, 2, 5],
+)
+pending_calls_metric = Histogram(
+    "python_twisted_reactor_pending_calls",
+    "Pending calls",
+    buckets=[1, 2, 5, 10, 25, 50, 100, 250, 500, 1000],
 )
 
-reactor_metrics = get_metrics_for("python.twisted.reactor")
-tick_time = reactor_metrics.register_distribution("tick_time")
-pending_calls_metric = reactor_metrics.register_distribution("pending_calls")
+#
+# Federation Metrics
+#
+
+sent_edus_counter = Counter("synapse_federation_client_sent_edus", "")
 
-synapse_metrics = get_metrics_for("synapse")
+sent_transactions_counter = Counter("synapse_federation_client_sent_transactions", "")
+
+events_processed_counter = Counter("synapse_federation_client_events_processed", "")
 
 # Used to track where various components have processed in the event stream,
 # e.g. federation sending, appservice sending, etc.
-event_processing_positions = synapse_metrics.register_gauge(
-    "event_processing_positions", labels=["name"],
-)
+event_processing_positions = Gauge("synapse_event_processing_positions", "", ["name"])
 
 # Used to track the current max events stream position
-event_persisted_position = synapse_metrics.register_gauge(
-    "event_persisted_position",
-)
+event_persisted_position = Gauge("synapse_event_persisted_position", "")
 
 # Used to track the received_ts of the last event processed by various
 # components
-event_processing_last_ts = synapse_metrics.register_gauge(
-    "event_processing_last_ts", labels=["name"],
-)
+event_processing_last_ts = Gauge("synapse_event_processing_last_ts", "", ["name"])
 
 # Used to track the lag processing events. This is the time difference
 # between the last processed event's received_ts and the time it was
 # finished being processed.
-event_processing_lag = synapse_metrics.register_gauge(
-    "event_processing_lag", labels=["name"],
-)
+event_processing_lag = Gauge("synapse_event_processing_lag", "", ["name"])
 
 
 def runUntilCurrentTimer(func):
@@ -197,17 +202,17 @@ def runUntilCurrentTimer(func):
             num_pending += 1
 
         num_pending += len(reactor.threadCallQueue)
-        start = time.time() * 1000
+        start = time.time()
         ret = func(*args, **kwargs)
-        end = time.time() * 1000
+        end = time.time()
 
         # record the amount of wallclock time spent running pending calls.
         # This is a proxy for the actual amount of time between reactor polls,
         # since about 25% of time is actually spent running things triggered by
         # I/O events, but that is harder to capture without rewriting half the
         # reactor.
-        tick_time.inc_by(end - start)
-        pending_calls_metric.inc_by(num_pending)
+        tick_time.observe(end - start)
+        pending_calls_metric.observe(num_pending)
 
         if running_on_pypy:
             return ret
@@ -220,12 +225,12 @@ def runUntilCurrentTimer(func):
             if threshold[i] < counts[i]:
                 logger.info("Collecting gc %d", i)
 
-                start = time.time() * 1000
+                start = time.time()
                 unreachable = gc.collect(i)
-                end = time.time() * 1000
+                end = time.time()
 
-                gc_time.inc_by(end - start, i)
-                gc_unreachable.inc_by(unreachable, i)
+                gc_time.labels(i).observe(end - start)
+                gc_unreachable.labels(i).set(unreachable)
 
         return ret