From 7c1a92274c720f125e8c5bb96b85f05734a58943 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Mon, 8 Aug 2016 11:12:21 +0100
Subject: [PATCH] Make psutil optional

---
 synapse/metrics/__init__.py    | 13 +++++++++++--
 synapse/metrics/metric.py      |  5 ++---
 synapse/python_dependencies.py |  4 +++-
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index cce3dba47..76d5998d7 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -68,9 +68,18 @@ class Metrics(object):
 
 
 def register_memory_metrics(hs):
-    metric = MemoryUsageMetric(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)
-    return metric
 
 
 def get_metrics_for(pkg_name):
diff --git a/synapse/metrics/metric.py b/synapse/metrics/metric.py
index 7becbe049..e81af2989 100644
--- a/synapse/metrics/metric.py
+++ b/synapse/metrics/metric.py
@@ -16,8 +16,6 @@
 
 from itertools import chain
 
-import psutil
-
 
 # TODO(paul): I can't believe Python doesn't have one of these
 def map_concat(func, items):
@@ -167,9 +165,10 @@ class MemoryUsageMetric(object):
     UPDATE_HZ = 2  # number of times to get memory per second
     WINDOW_SIZE_SEC = 30  # the size of the window in seconds
 
-    def __init__(self, hs):
+    def __init__(self, hs, psutil):
         clock = hs.get_clock()
         self.memory_snapshots = []
+
         self.process = psutil.Process()
 
         clock.looping_call(self._update_curr_values, 1000 / self.UPDATE_HZ)
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 799d35da5..86e3d8915 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -36,7 +36,6 @@ REQUIREMENTS = {
     "blist": ["blist"],
     "pysaml2>=3.0.0,<4.0.0": ["saml2>=3.0.0,<4.0.0"],
     "pymacaroons-pynacl": ["pymacaroons"],
-    "psutil>=2.0.0": ["psutil>=2.0.0"],
 }
 CONDITIONAL_REQUIREMENTS = {
     "web_client": {
@@ -52,6 +51,9 @@ CONDITIONAL_REQUIREMENTS = {
     "ldap": {
         "ldap3>=1.0": ["ldap3>=1.0"],
     },
+    "psutil": {
+        "psutil>=2.0.0": ["psutil>=2.0.0"],
+    },
 }