Emissary is a data plane for Envoy https://github.com/envoyproxy/data-plane-api/blob/master/XDS_PROTOCOL.md

Emissary currently supports Consul or Docker API resolvers.

The Consul resolver will resolve the service to a list of endpoints using the name of the configured virtual host.

The Docker resolver will be looking for a label to identify the destination containers for Envoy. By default the label is emissary.service_name but can be override in the configuration.

dep ensure
make

make will build a single executable emissary and tag a docker image emissary:latest

Run the tests using make:

$ make test
# For more verbosity (`Q=` trick applies to all targets)
$ make test Q=

examples/eds_grpc and examples/eds_az_aware_grpc are two examples on how to use Emissary with Consul.

cd examples/eds_grpc
make
docker-compose up

cd examples/eds_az_aware_grpc
make
docker-compose up

Each example starts 2 "server" containers, which run a trivial http server listening on port 8077. It then starts an envoy instance to serve as the loadbalancer for the upstream server clusters. Additionally we start consul and registrator containers. Finally we start a client which connects to server clusters via envoy.

The examples share the same containers so if you start and stop different examples you may need to clean your stopped containers

docker rm $(docker ps -qa --no-trunc --filter "status=exited")

You can use Emissary to discover local Docker containers and load balance traffic to those via Envoy. You can find a example for this pattern in examples/docker_resolver.

cd examples/docker_resolver
make up