Trapping dependencies Exceptions into TransportConnectionFailed (#558)

Author: leszekhanusz

docs/advanced/error_handling.rst

@@ -46,6 +46,11 @@ Here are the possible Transport Errors:
   If you don't need the schema, you can try to create the client with
   :code:`fetch_schema_from_transport=False`
 
+- :class:`TransportConnectionFailed <gql.transport.exceptions.TransportConnectionFailed>`:
+  This exception is generated when an unexpected Exception is received from the
+  transport dependency when trying to connect or to send the request.
+  For example in case of an SSL error, or if a websocket connection suddenly fails.
+
 - :class:`TransportClosed <gql.transport.exceptions.TransportClosed>`:
   This exception is generated when the client is trying to use the transport
   while the transport was previously closed.

gql/gql.py

@@ -3,15 +3,14 @@
 
 def gql(request_string: str) -> GraphQLRequest:
     """Given a string containing a GraphQL request,
-       parse it into a Document and put it into a GraphQLRequest object
+       parse it into a Document and put it into a GraphQLRequest object.
 
     :param request_string: the GraphQL request as a String
     :return: a :class:`GraphQLRequest <gql.GraphQLRequest>`
              which can be later executed or subscribed by a
-        :class:`Client <gql.client.Client>`, by an
-        :class:`async session <gql.client.AsyncClientSession>` or by a
-        :class:`sync session <gql.client.SyncClientSession>`
-
+             :class:`Client <gql.client.Client>`, by an
+             :class:`async session <gql.client.AsyncClientSession>` or by a
+             :class:`sync session <gql.client.SyncClientSession>`
     :raises graphql.error.GraphQLError: if a syntax error is encountered.
     """
     return GraphQLRequest(request_string)

gql/graphql_request.py

@@ -14,22 +14,19 @@ def __init__(
         variable_values: Optional[Dict[str, Any]] = None,
         operation_name: Optional[str] = None,
     ):
-        """
-        Initialize a GraphQL request.
+        """Initialize a GraphQL request.
 
         :param request: GraphQL request as DocumentNode object or as a string.
              If string, it will be converted to DocumentNode.
         :param variable_values: Dictionary of input parameters (Default: None).
         :param operation_name: Name of the operation that shall be executed.
             Only required in multi-operation documents (Default: None).
-
         :return: a :class:`GraphQLRequest <gql.GraphQLRequest>`
                  which can be later executed or subscribed by a
-            :class:`Client <gql.client.Client>`, by an
-            :class:`async session <gql.client.AsyncClientSession>` or by a
-            :class:`sync session <gql.client.SyncClientSession>`
+                 :class:`Client <gql.client.Client>`, by an
+                 :class:`async session <gql.client.AsyncClientSession>` or by a
+                 :class:`sync session <gql.client.SyncClientSession>`
         :raises graphql.error.GraphQLError: if a syntax error is encountered.
-
         """
         if isinstance(request, str):
             source = Source(request, "GraphQL request")

gql/transport/aiohttp.py

@@ -31,6 +31,8 @@
 from .exceptions import (
     TransportAlreadyConnected,
     TransportClosed,
+    TransportConnectionFailed,
+    TransportError,
     TransportProtocolError,
     TransportServerError,
 )
@@ -377,6 +379,10 @@ async def execute(
         try:
             async with self.session.post(self.url, ssl=self.ssl, **post_args) as resp:
                 return await self._prepare_result(resp)
+        except TransportError:
+            raise
+        except Exception as e:
+            raise TransportConnectionFailed(str(e)) from e
         finally:
             if upload_files:
                 close_files(list(self.files.values()))
@@ -407,8 +413,13 @@ async def execute_batch(
             extra_args,
         )
 
-        async with self.session.post(self.url, ssl=self.ssl, **post_args) as resp:
-            return await self._prepare_batch_result(reqs, resp)
+        try:
+            async with self.session.post(self.url, ssl=self.ssl, **post_args) as resp:
+                return await self._prepare_batch_result(reqs, resp)
+        except TransportError:
+            raise
+        except Exception as e:
+            raise TransportConnectionFailed(str(e)) from e
 
     def subscribe(
         self,

gql/transport/exceptions.py

@@ -62,9 +62,10 @@ class TransportClosed(TransportError):
 
 
 class TransportConnectionFailed(TransportError):
-    """Transport adapter connection closed.
+    """Transport connection failed.
 
-    This exception is by the connection adapter code when a connection closed.
+    This exception is by the connection adapter code when a connection closed
+    or if an unexpected Exception was received when trying to send a request.
     """
 
 

gql/transport/httpx.py

@@ -23,6 +23,7 @@
 from .exceptions import (
     TransportAlreadyConnected,
     TransportClosed,
+    TransportConnectionFailed,
     TransportProtocolError,
     TransportServerError,
 )
@@ -262,6 +263,8 @@ def execute(
 
         try:
             response = self.client.post(self.url, **post_args)
+        except Exception as e:
+            raise TransportConnectionFailed(str(e)) from e
         finally:
             if upload_files:
                 close_files(list(self.files.values()))
@@ -294,7 +297,10 @@ def execute_batch(
             extra_args=extra_args,
         )
 
-        response = self.client.post(self.url, **post_args)
+        try:
+            response = self.client.post(self.url, **post_args)
+        except Exception as e:
+            raise TransportConnectionFailed(str(e)) from e
 
         return self._prepare_batch_result(reqs, response)
 
@@ -354,6 +360,8 @@ async def execute(
 
         try:
             response = await self.client.post(self.url, **post_args)
+        except Exception as e:
+            raise TransportConnectionFailed(str(e)) from e
         finally:
             if upload_files:
                 close_files(list(self.files.values()))
@@ -386,7 +394,10 @@ async def execute_batch(
             extra_args=extra_args,
         )
 
-        response = await self.client.post(self.url, **post_args)
+        try:
+            response = await self.client.post(self.url, **post_args)
+        except Exception as e:
+            raise TransportConnectionFailed(str(e)) from e
 
         return self._prepare_batch_result(reqs, response)
 

gql/transport/requests.py

@@ -29,6 +29,7 @@
 from .exceptions import (
     TransportAlreadyConnected,
     TransportClosed,
+    TransportConnectionFailed,
     TransportProtocolError,
     TransportServerError,
 )
@@ -289,6 +290,8 @@ def execute(
         # Using the created session to perform requests
         try:
             response = self.session.request(self.method, self.url, **post_args)
+        except Exception as e:
+            raise TransportConnectionFailed(str(e)) from e
         finally:
             if upload_files:
                 close_files(list(self.files.values()))
@@ -349,11 +352,14 @@ def execute_batch(
             extra_args=extra_args,
         )
 
-        response = self.session.request(
-            self.method,
-            self.url,
-            **post_args,
-        )
+        try:
+            response = self.session.request(
+                self.method,
+                self.url,
+                **post_args,
+            )
+        except Exception as e:
+            raise TransportConnectionFailed(str(e)) from e
 
         return self._prepare_batch_result(reqs, response)
 

tests/test_aiohttp.py

@@ -11,6 +11,7 @@
 from gql.transport.exceptions import (
     TransportAlreadyConnected,
     TransportClosed,
+    TransportConnectionFailed,
     TransportProtocolError,
     TransportQueryError,
     TransportServerError,
@@ -1455,7 +1456,6 @@ async def handler(request):
 async def test_aiohttp_query_https_self_cert_fail(ssl_aiohttp_server):
     """By default, we should verify the ssl certificate"""
     from aiohttp import web
-    from aiohttp.client_exceptions import ClientConnectorCertificateError
 
     from gql.transport.aiohttp import AIOHTTPTransport
 
@@ -1472,16 +1472,22 @@ async def handler(request):
 
     transport = AIOHTTPTransport(url=url, timeout=10)
 
-    with pytest.raises(ClientConnectorCertificateError) as exc_info:
-        async with Client(transport=transport) as session:
-            query = gql(query1_str)
+    query = gql(query1_str)
 
-            # Execute query asynchronously
+    expected_error = "certificate verify failed: self-signed certificate"
+
+    with pytest.raises(TransportConnectionFailed) as exc_info:
+        async with Client(transport=transport) as session:
             await session.execute(query)
 
-    expected_error = "certificate verify failed: self-signed certificate"
+    assert expected_error in str(exc_info.value)
+
+    with pytest.raises(TransportConnectionFailed) as exc_info:
+        async with Client(transport=transport) as session:
+            await session.execute_batch([query])
 
     assert expected_error in str(exc_info.value)
+
     assert transport.session is None
 
 

tests/test_httpx.py

@@ -7,6 +7,7 @@
 from gql.transport.exceptions import (
     TransportAlreadyConnected,
     TransportClosed,
+    TransportConnectionFailed,
     TransportProtocolError,
     TransportQueryError,
     TransportServerError,
@@ -150,7 +151,6 @@ async def test_httpx_query_https_self_cert_fail(
 ):
     """By default, we should verify the ssl certificate"""
     from aiohttp import web
-    from httpx import ConnectError
 
     from gql.transport.httpx import HTTPXTransport
 
@@ -180,15 +180,19 @@ def test_code():
             **extra_args,
         )
 
-        with pytest.raises(ConnectError) as exc_info:
-            with Client(transport=transport) as session:
+        query = gql(query1_str)
 
-                query = gql(query1_str)
+        expected_error = "certificate verify failed: self-signed certificate"
 
-                # Execute query synchronously
+        with pytest.raises(TransportConnectionFailed) as exc_info:
+            with Client(transport=transport) as session:
                 session.execute(query)
 
-        expected_error = "certificate verify failed: self-signed certificate"
+        assert expected_error in str(exc_info.value)
+
+        with pytest.raises(TransportConnectionFailed) as exc_info:
+            with Client(transport=transport) as session:
+                session.execute_batch([query])
 
         assert expected_error in str(exc_info.value)
 

tests/test_httpx_async.py

@@ -9,6 +9,7 @@
 from gql.transport.exceptions import (
     TransportAlreadyConnected,
     TransportClosed,
+    TransportConnectionFailed,
     TransportProtocolError,
     TransportQueryError,
     TransportServerError,
@@ -1155,7 +1156,6 @@ async def handler(request):
 @pytest.mark.parametrize("verify_https", ["explicitely_enabled", "default"])
 async def test_httpx_query_https_self_cert_fail(ssl_aiohttp_server, verify_https):
     from aiohttp import web
-    from httpx import ConnectError
 
     from gql.transport.httpx import HTTPXAsyncTransport
 
@@ -1177,15 +1177,19 @@ async def handler(request):
 
     transport = HTTPXAsyncTransport(url=url, timeout=10, **extra_args)
 
-    with pytest.raises(ConnectError) as exc_info:
-        async with Client(transport=transport) as session:
+    query = gql(query1_str)
 
-            query = gql(query1_str)
+    expected_error = "certificate verify failed: self-signed certificate"
 
-            # Execute query asynchronously
+    with pytest.raises(TransportConnectionFailed) as exc_info:
+        async with Client(transport=transport) as session:
             await session.execute(query)
 
-    expected_error = "certificate verify failed: self-signed certificate"
+    assert expected_error in str(exc_info.value)
+
+    with pytest.raises(TransportConnectionFailed) as exc_info:
+        async with Client(transport=transport) as session:
+            await session.execute_batch([query])
 
     assert expected_error in str(exc_info.value)