fix: return 404 for invalid URL's for consistency

URL's that are invalid should return a 404, just like any other
invalid URL.

Closes #578

.travis.yml

@@ -14,6 +14,3 @@ after_success:
 notifications:
   slack:
     secure: LE+1Nelh5PLrb35LU6yJI1EV2LDVm4V90Tb+5LhUpeGrcfqr47HhMLMGXbBSnnjYPRLCiT75xog+oMN5eAF4VnZle4qza6Ue7G+YwRtGo/V0ud0i2zSUT557yXcr2QCYAzTKJVgetnxQNYvru/l1trdNZsRbsPUm1vexAjaX5yo=
-addons:
-  hostname: push.mozilla.com
-

autopush/metrics.py

@@ -71,9 +71,10 @@ def timing(self, name, duration, **kwargs):
 class DatadogMetrics(object):
     """DataDog Metric backend"""
     def __init__(self, api_key, app_key, flush_interval=10,
-                 namespace="autopush"):
+                 namespace="autopush", hostname="localhost"):
 
-        datadog.initialize(api_key=api_key, app_key=app_key)
+        datadog.initialize(api_key=api_key, app_key=app_key,
+                           host_name=hostname)
         self._client = ThreadStats()
         self._flush_interval = flush_interval
         self._host = get_hostname()

autopush/settings.py

@@ -100,17 +100,6 @@ def __init__(self,
         pool = HTTPConnectionPool(reactor)
         self.agent = Agent(reactor, connectTimeout=5, pool=pool)
 
-        # Metrics setup
-        if datadog_api_key:
-            self.metrics = DatadogMetrics(
-                api_key=datadog_api_key,
-                app_key=datadog_app_key,
-                flush_interval=datadog_flush_interval
-            )
-        elif statsd_host:
-            self.metrics = TwistedMetrics(statsd_host, statsd_port)
-        else:
-            self.metrics = SinkMetrics()
         if not crypto_key:
             crypto_key = [Fernet.generate_key()]
         if not isinstance(crypto_key, list):
@@ -133,6 +122,19 @@ def __init__(self,
         if resolve_hostname:
             self.hostname = resolve_ip(self.hostname)
 
+        # Metrics setup
+        if datadog_api_key:
+            self.metrics = DatadogMetrics(
+                api_key=datadog_api_key,
+                app_key=datadog_app_key,
+                flush_interval=datadog_flush_interval,
+                hostname=self.hostname,
+            )
+        elif statsd_host:
+            self.metrics = TwistedMetrics(statsd_host, statsd_port)
+        else:
+            self.metrics = SinkMetrics()
+
         self.port = port
         self.endpoint_hostname = endpoint_hostname or self.hostname
         self.router_hostname = router_hostname or self.hostname