Extending Envoy for custom use cases

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

• Access loggers

• Access log filters

• Clusters

• Listener filters

• Network filters

• HTTP filters

• gRPC credential providers

• Health checkers

• Resource monitors

• Retry implementations

• Stat sinks

• Tracers

• Request ID

• Transport sockets

• BoringSSL private key methods

• Watchdog action

• Internal redirect policy

• Compression libraries

• Bootstrap extensions

• Fatal actions

• Formatters

• Connection balance extensions

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.