2 files changed, 25 insertions, 11 deletions
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index cd0e815919..cf4730730d 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -12,10 +12,16 @@
 # 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 gc
 import logging
+import sys
+
+try:
+    import affinity
+except:
+    affinity = None
 
-import affinity
 from daemonize import Daemonize
 from synapse.util import PreserveLoggingContext
 from synapse.util.rlimit import change_resource_limit
@@ -78,6 +84,13 @@ def start_reactor(
         with PreserveLoggingContext():
             logger.info("Running")
             if cpu_affinity is not None:
+                if not affinity:
+                    quit_with_error(
+                        "Missing package 'affinity' required for cpu_affinity\n"
+                        "option\n\n"
+                        "Install by running:\n\n"
+                        "   pip install affinity\n\n"
+                    )
                 logger.info("Setting CPU affinity to %s" % cpu_affinity)
                 affinity.set_process_affinity_mask(0, cpu_affinity)
             change_resource_limit(soft_file_limit)
@@ -97,3 +110,13 @@ def start_reactor(
         daemon.start()
     else:
         run()
+
+
+def quit_with_error(error_string):
+    message_lines = error_string.split("\n")
+    line_length = max([len(l) for l in message_lines if len(l) < 80]) + 2
+    sys.stderr.write("*" * line_length + '\n')
+    for line in message_lines:
+        sys.stderr.write(" %s\n" % (line.rstrip(),))
+    sys.stderr.write("*" * line_length + '\n')
+    sys.exit(1)
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 84ad8f04a0..3adf72e141 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -25,6 +25,7 @@ from synapse.api.urls import CONTENT_REPO_PREFIX, FEDERATION_PREFIX, \
     LEGACY_MEDIA_PREFIX, MEDIA_PREFIX, SERVER_KEY_PREFIX, SERVER_KEY_V2_PREFIX, \
     STATIC_PREFIX, WEB_CLIENT_PREFIX
 from synapse.app import _base
+from synapse.app._base import quit_with_error
 from synapse.config._base import ConfigError
 from synapse.config.homeserver import HomeServerConfig
 from synapse.crypto import context_factory
@@ -249,16 +250,6 @@ class SynapseHomeServer(HomeServer):
         return db_conn
 
 
-def quit_with_error(error_string):
-    message_lines = error_string.split("\n")
-    line_length = max([len(l) for l in message_lines if len(l) < 80]) + 2
-    sys.stderr.write("*" * line_length + '\n')
-    for line in message_lines:
-        sys.stderr.write(" %s\n" % (line.rstrip(),))
-    sys.stderr.write("*" * line_length + '\n')
-    sys.exit(1)
-
-
 def setup(config_options):
     """
     Args: