From fce10cdaa68f2f47a3d398d0a603d0996b6720d4 Mon Sep 17 00:00:00 2001
From: James Muscat <jamesremuscat@gmail.com>
Date: Thu, 9 Apr 2015 00:35:27 +0100
Subject: [PATCH] Simple stat collector, to better monitor gateway throughput
 and health.

---
 src/eddn/Gateway.py        | 25 ++++++++++++++++++++
 src/eddn/StatsCollector.py | 48 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 src/eddn/StatsCollector.py

diff --git a/src/eddn/Gateway.py b/src/eddn/Gateway.py
index 6637880..53c2138 100644
--- a/src/eddn/Gateway.py
+++ b/src/eddn/Gateway.py
@@ -33,6 +33,11 @@ validator = Validator()
 for schemaRef, schemaFile in Settings.GATEWAY_JSON_SCHEMAS.iteritems():
     validator.addSchemaResource(schemaRef, schemaFile)
 
+# This import must be done post-monkey-patching!
+from eddn.StatsCollector import StatsCollector
+statsCollector = StatsCollector()
+statsCollector.start()
+
 
 def push_message(string_message):
     """
@@ -45,6 +50,7 @@ def push_message(string_message):
     # announcers.
     compressed_msg = zlib.compress(string_message)
     sender.send(compressed_msg)
+    statsCollector.tallyOutbound()
 
 
 def get_remote_address():
@@ -158,6 +164,7 @@ def upload():
         logger.error("Error to %s: %s" % (get_remote_address(), exc.message))
         return exc.message
 
+    statsCollector.tallyInbound()
     return parse_and_error_handle(message_body)
 
 
@@ -171,6 +178,24 @@ def health_check():
     return Settings.EDDN_VERSION
 
 
+@get('/stats/')
+def stats():
+    return simplejson.dumps(
+        {
+            "inbound": {
+                "1min": statsCollector.getInboundCount(1),
+                "5min": statsCollector.getInboundCount(5),
+                "60min": statsCollector.getInboundCount(60)
+            },
+            "outbound": {
+                "1min": statsCollector.getOutboundCount(1),
+                "5min": statsCollector.getOutboundCount(5),
+                "60min": statsCollector.getOutboundCount(60)
+            },
+        }
+    )
+
+
 class MalformedUploadError(Exception):
     """
     Raise this when an upload is structurally incorrect. This isn't so much
diff --git a/src/eddn/StatsCollector.py b/src/eddn/StatsCollector.py
new file mode 100644
index 0000000..1876f32
--- /dev/null
+++ b/src/eddn/StatsCollector.py
@@ -0,0 +1,48 @@
+from collections import deque
+from itertools import islice
+from threading import Lock, Thread
+from time import sleep
+
+
+class StatsCollector(Thread):
+    '''
+    Collects simple statistics - number of inbound vs. outbound messages - and
+    aggregates them over the number of minutes you choose, up to one hour.
+    '''
+
+    max_minutes = 60
+
+    inboundMessages = 0
+    outboundMessages = 0
+
+    inboundHistory = deque(maxlen=max_minutes)
+    outboundHistory = deque(maxlen=max_minutes)
+
+    lock = Lock()
+
+    def __init__(self):
+        super(StatsCollector, self).__init__()
+        self.daemon = True
+
+    def run(self):
+        while True:
+            sleep(60)
+            with self.lock:
+                self.inboundHistory.append(self.inboundMessages)
+                self.outboundHistory.append(self.outboundMessages)
+                self.inboundMessages = 0
+                self.outboundMessages = 0
+
+    def tallyInbound(self):
+        with self.lock:
+            self.inboundMessages += 1
+
+    def tallyOutbound(self):
+        with self.lock:
+            self.outboundMessages += 1
+
+    def getInboundCount(self, minutes):
+        return sum(islice(self.inboundHistory, 0, max(minutes, self.max_minutes)))
+
+    def getOutboundCount(self, minutes):
+        return sum(islice(self.outboundHistory, 0, max(minutes, self.max_minutes)))