Feature aiohttp and requests transports logging (#157)

Author: leszekhanusz

docs/advanced/index.rst

@@ -5,5 +5,6 @@ Advanced
    :maxdepth: 2
 
    async_advanced_usage
+   logging
    local_schema
    dsl_module

docs/advanced/logging.rst

@@ -0,0 +1,21 @@
+Logging
+=======
+
+GQL use the python `logging`_ module.
+
+In order to debug a problem, you can enable logging to see the messages exchanged between the client and the server.
+To do that, set the loglevel at **INFO** at the beginning of your code:
+
+.. code-block:: python
+
+    import logging
+    logging.basicConfig(level=logging.INFO)
+
+For even more logs, you can set the loglevel at **DEBUG**:
+
+.. code-block:: python
+
+    import logging
+    logging.basicConfig(level=logging.DEBUG)
+
+.. _logging: https://docs.python.org/3/howto/logging.html

gql/transport/aiohttp.py

@@ -183,6 +183,9 @@ async def execute(
             if variable_values:
                 payload["variables"] = variable_values
 
+            if log.isEnabledFor(logging.INFO):
+                log.info(">>> %s", json.dumps(payload))
+
             post_args = {"json": payload}
 
         # Pass post_args to aiohttp post method
@@ -195,6 +198,10 @@ async def execute(
         async with self.session.post(self.url, ssl=self.ssl, **post_args) as resp:
             try:
                 result = await resp.json()
+
+                if log.isEnabledFor(logging.INFO):
+                    result_text = await resp.text()
+                    log.info("<<< %s", result_text)
             except Exception:
                 # We raise a TransportServerError if the status code is 400 or higher
                 # We raise a TransportProtocolError in the other cases

gql/transport/requests.py

@@ -1,3 +1,5 @@
+import json
+import logging
 from typing import Any, Dict, Optional, Union
 
 import requests
@@ -15,6 +17,8 @@
     TransportServerError,
 )
 
+log = logging.getLogger(__name__)
+
 
 class RequestsHTTPTransport(Transport):
     """:ref:`Sync Transport <sync_transports>` used to execute GraphQL queries
@@ -135,6 +139,10 @@ def execute(  # type: ignore
             data_key: payload,
         }
 
+        # Log the payload
+        if log.isEnabledFor(logging.INFO):
+            log.info(">>> %s", json.dumps(payload))
+
         # Pass kwargs to requests post method
         post_args.update(self.kwargs)
 
@@ -144,6 +152,9 @@ def execute(  # type: ignore
         )
         try:
             result = response.json()
+
+            if log.isEnabledFor(logging.INFO):
+                log.info("<<< %s", response.text)
         except Exception:
             # We raise a TransportServerError if the status code is 400 or higher
             # We raise a TransportProtocolError in the other cases