feat: make gcm calls use async callbacks

Closes #1291

autopush/router/gcm.py

@@ -1,9 +1,8 @@
 """GCM Router"""
 from typing import Any  # noqa
 
-from requests.exceptions import ConnectionError, Timeout
-from twisted.internet.threads import deferToThread
 from twisted.logger import Logger
+from twisted.internet.error import ConnectError, TimeoutError
 
 from autopush.exceptions import RouterException
 from autopush.metrics import make_tags
@@ -28,15 +27,16 @@ def __init__(self, conf, router_conf, metrics):
         self.dryRun = router_conf.get("dryrun", False)
         self.collapseKey = router_conf.get("collapseKey")
         timeout = router_conf.get("timeout", 10)
-        self.gcm = {}
+        self.gcmclients = {}
         self.senderIDs = {}
         # Flatten the SenderID list from human readable and init gcmclient
         if not router_conf.get("senderIDs"):
             raise IOError("SenderIDs not configured.")
         for sid in router_conf.get("senderIDs"):
             auth = router_conf.get("senderIDs").get(sid).get("auth")
             self.senderIDs[sid] = auth
-            self.gcm[sid] = gcmclient.GCM(auth, timeout=timeout)
+            self.gcmclients[sid] = gcmclient.GCM(auth, timeout=timeout,
+                                                 logger=self.log)
         self._base_tags = ["platform:gcm"]
         self.log.debug("Starting GCM router...")
 
@@ -69,7 +69,7 @@ def register(self, uaid, router_data, app_id, *args, **kwargs):
     def route_notification(self, notification, uaid_data):
         """Start the GCM notification routing, returns a deferred"""
         # Kick the entire notification routing off to a thread
-        return deferToThread(self._route, notification, uaid_data)
+        return self._route(notification, uaid_data)
 
     def _route(self, notification, uaid_data):
         """Blocking GCM call to route the notification"""
@@ -111,41 +111,48 @@ def _route(self, notification, uaid_data):
             data=data,
         )
         try:
-            gcm = self.gcm[router_data['creds']['senderID']]
-            result = gcm.send(payload)
-        except RouterException:
-            raise  # pragma nocover
+            client = self.gcmclients[router_data['creds']['senderID']]
+            d = client.send(payload)
+            d.addCallback(
+                self._process_reply,
+                uaid_data,
+                router_ttl,
+                notification)
+
+            d.addErrback(
+                self._process_error
+            )
+            return d
         except KeyError:
             self.log.critical("Missing GCM bridge credentials")
             raise RouterException("Server error", status_code=500,
                                   errno=900)
-        except gcmclient.GCMAuthenticationError as e:
-            self.log.error("GCM Authentication Error: %s" % e)
+
+    def _process_error(self, failure):
+        err = failure.value
+        if isinstance(err, gcmclient.GCMAuthenticationError):
+            self.log.error("GCM Authentication Error: %s" % err)
             raise RouterException("Server error", status_code=500,
                                   errno=901)
-        except ConnectionError as e:
-            self.log.warn("GCM Unavailable: %s" % e)
+        if isinstance(err, TimeoutError):
+            self.log.warn("GCM Timeout: %s" % err)
             self.metrics.increment("notification.bridge.error",
                                    tags=make_tags(
                                        self._base_tags,
-                                       reason="connection_unavailable"))
+                                       reason="timeout"))
             raise RouterException("Server error", status_code=502,
-                                  errno=902,
+                                  errno=903,
                                   log_exception=False)
-        except Timeout as e:
-            self.log.warn("GCM Timeout: %s" % e)
+        if isinstance(err, ConnectError):
+            self.log.warn("GCM Unavailable: %s" % err)
             self.metrics.increment("notification.bridge.error",
                                    tags=make_tags(
                                        self._base_tags,
-                                       reason="timeout"))
+                                       reason="connection_unavailable"))
             raise RouterException("Server error", status_code=502,
-                                  errno=903,
+                                  errno=902,
                                   log_exception=False)
-        except Exception as e:
-            self.log.error("Unhandled exception in GCM Routing: %s" % e)
-            raise RouterException("Server error", status_code=500)
-        return self._process_reply(result, uaid_data, ttl=router_ttl,
-                                   notification=notification)
+        return failure
 
     def _error(self, err, status, **kwargs):
         """Error handler that raises the RouterException"""

autopush/router/gcmclient.py

@@ -1,6 +1,9 @@
 import json
 
-import requests
+import treq
+from twisted.web.http_headers import Headers
+from twisted.logger import Logger
+from twisted.internet.error import ConnectError
 
 from autopush.exceptions import RouterException
 
@@ -12,7 +15,7 @@ class GCMAuthenticationError(Exception):
 class Result(object):
     """Abstraction object for GCM response"""
 
-    def __init__(self, message, response):
+    def __init__(self, response, message):
         """Process GCM message and response into abstracted object
 
         :param message: Message payload
@@ -30,14 +33,13 @@ def __init__(self, message, response):
         self.message = message
         self.retry_message = None
 
-        self.retry_after = response.headers.get('Retry-After', None)
+        self.retry_after = (
+            response.headers.getRawHeaders('Retry-After') or [None])[0]
 
-        if response.status_code != 200:
-            self.retry_message = message
-        else:
-            self._parse_response(message, response.content)
-
-    def _parse_response(self, message, content):
+    def parse_response(self, content, code, message):
+        # 401 handled in GCM.process()
+        if code in (400, 404):
+            raise RouterException(content)
         data = json.loads(content)
         if not data.get('results'):
             raise RouterException("Recv'd invalid response from GCM")
@@ -54,6 +56,7 @@ def _parse_response(self, message, content):
                     self.not_registered.append(reg_id)
                 else:
                     self.failed[reg_id] = res['error']
+        return self
 
 
 class JSONMessage(object):
@@ -124,9 +127,31 @@ def __init__(self,
         self._endpoint = "https://{}".format(endpoint)
         self._api_key = api_key
         self.metrics = metrics
-        self.log = logger
+        self.log = logger or Logger()
         self._options = options
-        self._sender = requests.post
+        self._sender = treq.post
+
+    def process(self, response, payload):
+        if response.code == 401:
+            raise GCMAuthenticationError("Authentication Error")
+
+        result = Result(response, payload)
+
+        if 500 <= response.code <= 599:
+            result.retry_message = payload
+            return result
+
+        # Fetch the content body
+        d = response.text()
+        d.addCallback(result.parse_response, response.code, payload)
+        return d
+
+    def error(self, failure):
+        if isinstance(failure.value, GCMAuthenticationError) or \
+                isinstance(failure.value, ConnectError):
+            raise failure.value
+        self.log.error("GCMClient failure: {}".format(failure.value))
+        raise RouterException("Server error: {}".format(failure.value))
 
     def send(self, payload):
         """Send a payload to GCM
@@ -136,23 +161,21 @@ def send(self, payload):
         :return: Result
 
         """
-        headers = {
-            'Content-Type': 'application/json',
-            'Authorization': 'key={}'.format(self._api_key),
-        }
+        headers = Headers({
+            'Content-Type': ['application/json'],
+            'Authorization': ['key={}'.format(self._api_key)],
+        })
+
+        if 'timeout' not in self._options:
+            self._options['timeout'] = 3
 
-        response = self._sender(
+        d = self._sender(
             url=self._endpoint,
             headers=headers,
             data=json.dumps(payload.payload),
             **self._options
         )
-
-        if response.status_code in (400, 404):
-            raise RouterException(response.content)
-
-        if response.status_code == 401:
-            raise GCMAuthenticationError("Authentication Error")
-
-        if response.status_code == 200 or (500 <= response.status_code <= 599):
-            return Result(payload, response)
+        # handle the immediate response (which contains no body)
+        d.addCallback(self.process, payload)
+        d.addErrback(self.error)
+        return d