gRPC Bridge¶
Envoy gRPC¶
The gRPC bridge sandbox is an example usage of Envoy’s 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
.
[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.
Running the Sandbox¶
The following documentation runs through the setup of Envoy described above.
Step 1: Install Docker¶
Ensure that you have a recent versions of docker
and docker-compose
installed.
A simple way to achieve this is via the Docker Desktop.
Step 2: Clone the Envoy repo¶
If you have not cloned the Envoy repo, clone it with:
git clone git@github.com:envoyproxy/envoy
git clone https://github.com/envoyproxy/envoy.git
Step 3: Generate the protocol stubs¶
A docker-compose file is provided that generates the stubs for both client
and server
from the
specification in the protos
directory.
Inspecting the 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:
$ 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:
$ docker container prune
You can view the generated kv
modules for both the client and server in their
respective directories:
$ 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 4: Start all of our containers¶
To build this sandbox example and start the example services, run the following commands:
$ 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, 0.0.0.0:9991->9991/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, 0.0.0.0:8881->8881/tcp
grpc-bridge_grpc-server_1 /bin/sh -c /bin/server Up 0.0.0.0:8081->8081/tcp
Sending requests to the Key/Value store¶
To use the Python service and send gRPC requests:
$ pwd
envoy/examples/grpc-bridge
Set a key:
$ docker-compose exec python /client/client.py set foo bar
setf foo to bar
Get a key:
$ docker-compose exec python /client/client.py get foo
bar
Modify an existing key:
$ docker-compose exec python /client/client.py set foo baz
setf foo to baz
Get the modified key:
$ docker-compose exec python /client/client.py get foo
baz
In the running docker-compose container, you should see the gRPC service printing a record of its activity:
$ 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