kinvolk / test-odcds

demo of Envoy lazy config loading

Test ODCDS

A dummy ODCDS server for Envoy.

Flow

1. A client sends an HTTP request to Envoy. Envoy doesn't know about the target cluster.
2. Envoy queries the ODCDS server for the cluster configuration using xDS.
3. The ODCDS server returns the cluster configuration.
4. Envoy sends an HTTP request to the cluster.
5. The cluster responds.
6. Envoy sends a response to the client.

Subsequent HTTP requests from the client don't trigger new xDS queries as long as the TTL of the cluster resource doesn't expire and Envoy isn't restarted.

Running

NOTE: We need 4 shells for experimenting with the server.

Run the ODCDS server in shell #1:

go run .

Run the dummy cluster in shell #2:

go run ./dummycluster

Run Envoy in shell #3:

# Configure the path to the Envoy binary.
export ENVOY_BIN=/tmp/envoy-bin/envoy

# Run Envoy.
$ENVOY_BIN --config-path examples/envoy.yaml

Send a request through Envoy in shell #4:

curl -H "Cluster-Name: foo" localhost:8080