Extending Envoy for custom use cases

The Envoy architecture makes it fairly easily extensible via a variety of differerent extension types including:

• Access loggers
• Clusters
• Listener filters
• Network filters
• HTTP filters
• gRPC credential providers
• Health checkers
• Resource monitors
• Retry implementations
• Stat sinks
• Tracers
• Transport sockets

As of this writing there is no high level extension developer documentation. The existing extensions are a good way to learn what is possible.

An example of how to add a network filter and structure the repository and build dependencies can be found at envoy-filter-example.