.. _install_sandboxes_grpc_bridge: gRPC bridge =========== .. sidebar:: Requirements .. include:: _include/docker-env-setup-link.rst The gRPC bridge sandbox is an example usage of Envoy's :ref:`gRPC bridge filter `. This is an example of a key-value store where an ``http``-based client CLI, written in ``Python``, updates a remote store, written in ``Go``, using the stubs generated for both languages. The client send messages through a proxy that upgrades the HTTP requests from ``http/1.1`` to ``http/2`` or ``http/3`` ``[client](http/1.1) -> [client-egress-proxy](http/2) -> [server-ingress-proxy](http/2) -> [server]`` Another Envoy feature demonstrated in this example is Envoy's ability to do authority base routing via its route configuration. Step 1: Generate the protocol stubs *********************************** Change to the ``examples/grpc-bridge`` directory. A docker-compose file is provided that generates the stubs for both ``client`` and ``server`` from the specification in the ``protos`` directory. Inspecting the :download:`docker-compose-protos.yaml <_include/grpc-bridge/docker-compose-protos.yaml>` file, you will see that it contains both the ``python`` and ``go`` gRPC protoc commands necessary for generating the protocol stubs. Generate the stubs as follows: .. code-block:: console $ pwd envoy/examples/grpc-bridge $ docker-compose -f docker-compose-protos.yaml up Starting grpc-bridge_stubs_python_1 ... done Starting grpc-bridge_stubs_go_1 ... done Attaching to grpc-bridge_stubs_go_1, grpc-bridge_stubs_python_1 grpc-bridge_stubs_go_1 exited with code 0 grpc-bridge_stubs_python_1 exited with code 0 You may wish to clean up left over containers with the following command: .. code-block:: console $ docker container prune You can view the generated ``kv`` modules for both the client and server in their respective directories: .. code-block:: console $ ls -la client/kv/kv_pb2.py -rw-r--r-- 1 mdesales CORP\Domain Users 9527 Nov 6 21:59 client/kv/kv_pb2.py $ ls -la server/kv/kv.pb.go -rw-r--r-- 1 mdesales CORP\Domain Users 9994 Nov 6 21:59 server/kv/kv.pb.go These generated ``python`` and ``go`` stubs can be included as external modules. Step 2: Start all of our containers *********************************** To build this sandbox example and start the example services, run the following commands: .. code-block:: console $ pwd envoy/examples/grpc-bridge $ docker-compose pull $ docker-compose up --build -d $ docker-compose ps Name Command State Ports --------------------------------------------------------------------------------------------------------------- grpc-bridge_grpc-client-proxy_1 /docker-entrypoint.sh /bin ... Up 10000/tcp, 0.0.0.0:9911->9911/tcp grpc-bridge_grpc-client_1 /bin/sh -c tail -f /dev/null Up grpc-bridge_grpc-server-proxy_1 /docker-entrypoint.sh /bin ... Up 10000/tcp, 0.0.0.0:8811->8811/tcp grpc-bridge_grpc-server_1 /bin/sh -c /bin/server Up 0.0.0.0:8081->8081/tcp Step 3: Send requests to the Key/Value store ******************************************** To use the Python service and send gRPC requests: .. code-block:: console $ pwd envoy/examples/grpc-bridge Set a key: .. code-block:: console $ docker-compose exec grpc-client python /client/grpc-kv-client.py set foo bar setf foo to bar Get a key: .. code-block:: console $ docker-compose exec grpc-client python /client/grpc-kv-client.py get foo bar Modify an existing key: .. code-block:: console $ docker-compose exec grpc-client python /client/grpc-kv-client.py set foo baz setf foo to baz Get the modified key: .. code-block:: console $ docker-compose exec grpc-client python /client/grpc-kv-client.py get foo baz In the running docker-compose container, you should see the gRPC service printing a record of its activity: .. code-block:: console $ docker-compose logs grpc-server grpc_1 | 2017/05/30 12:05:09 set: foo = bar grpc_1 | 2017/05/30 12:05:12 get: foo grpc_1 | 2017/05/30 12:05:18 set: foo = baz .. seealso:: :ref:`gRPC bridge filter `. Learn more about configuring Envoy's gRPC bridge filter.