Add statsd helpers and wrappers

(imported from commit 9d5b805ae416a65ac49dda8e8e11d9831308116c)

zephyr/lib/utils.py

@@ -1,6 +1,50 @@
 # -*- coding: utf-8 -*-
 import hashlib
-from time import sleep
+from time import sleep, time
+from django.conf import settings
+
+def statsd_key(val):
+    if not isinstance(val, str):
+        val = str(val)
+
+    if ':' in val:
+        val = val.split(':')[0]
+    val = val.replace('-', "_")
+
+    return val
+
+class StatsDWrapper(object):
+    """Transparently either submit metrics to statsd
+    or do nothing without erroring out"""
+
+    # Backported support for gauge deltas
+    # as our statsd server supports them but supporting
+    # pystatsd is not released yet
+    def _our_gauge(self, stat, value, rate=1, delta=False):
+            """Set a gauge value."""
+            from django_statsd.clients import statsd
+            if delta:
+                value = '%+g|g' % value
+            else:
+                value = '%g|g' % value
+            statsd._send(stat, value, rate)
+
+    def __getattr__(self, name):
+        # Hand off to statsd if we have it enabled
+        # otherwise do nothing
+        if name in ['timer', 'timing', 'incr', 'decr', 'gauge']:
+            if settings.USING_STATSD:
+                from django_statsd.clients import statsd
+                if name == 'gauge':
+                    return self._our_gauge
+                else:
+                    return getattr(statsd, name)
+            else:
+                return lambda *args, **kwargs: None
+
+        raise AttributeError
+
+statsd = StatsDWrapper()
 
 # Runs the callback with slices of all_list of a given batch_size
 def run_in_batches(all_list, batch_size, callback, sleep_time = 0, logger = None):
@@ -30,3 +74,18 @@ def make_safe_digest(string, hash_func=hashlib.sha1):
     # hashlib.sha1, md5, etc. expect bytes, so non-ASCII strings must
     # be encoded.
     return hash_func(string.encode('utf-8')).hexdigest()
+
+
+def log_statsd_event(name):
+    """
+    Sends a single event to statsd with the desired name and the current timestamp
+
+    This can be used to provide vertical lines in generated graphs,
+    for example when doing a prod deploy, bankruptcy request, or
+    other one-off events
+
+    Note that to draw this event as a vertical line in graphite
+    you can use the drawAsInfinite() command
+    """
+    event_name = "events.%s" % (name,)
+    statsd.gauge(event_name, int(time()))