What is Envoy?
Who uses Envoy?
Why developers like Envoy?
Here are some stack decisions, common use cases and reviews by companies and developers who chose Envoy in their tech stack.
We just launched the Segment Config API (try it out for yourself here) — a set of public REST APIs that enable you to manage your Segment configuration. Behind the scenes the Config API is built with Go , GRPC and Envoy.
At Segment, we build new services in Go by default. The language is simple so new team members quickly ramp up on a codebase. The tool chain is fast so developers get immediate feedback when they break code, tests or integrations with other systems. The runtime is fast so it performs great at scale.
For the newest round of APIs we adopted the GRPC service #framework.
The Protocol Buffer service definition language makes it easy to design type-safe and consistent APIs, thanks to ecosystem tools like the Google API Design Guide for API standards,
uber/prototool for formatting and linting .protos and
lyft/protoc-gen-validate for defining field validations, and
grpc-gateway for defining REST mapping.
With a well designed .proto, its easy to generate a Go server interface and a TypeScript client, providing type-safe RPC between languages.
For the API gateway and RPC we adopted the Envoy service proxy.
segmentapis.com endpoint is an Envoy front proxy that rate-limits and authenticates every request. It then transcodes a #REST / #JSON request to an upstream GRPC request. The upstream GRPC servers are running an Envoy sidecar configured for Datadog stats.
The result is API #security , #reliability and consistent #observability through Envoy configuration, not code.
We experimented with Swagger service definitions, but the spec is sprawling and the generated clients and server stubs leave a lot to be desired. GRPC and .proto and the Go implementation feels better designed and implemented. Thanks to the GRPC tooling and ecosystem you can generate Swagger from .protos, but it’s effectively impossible to go the other way.
At uSwitch we wanted a way to load balance between our multiple Kubernetes clusters in AWS to give us added redundancy. We already had ingresses defined for all our applications so we wanted to build on top of that, instead of creating a new system that would require our various teams to change code/config etc.
Envoy seemed to tick a lot of boxes:
- Loadbalancing capabilities right out of the box: health checks, circuit breaking, retries etc.
- Tracing and prometheus metrics support
- Good community support
This was all good but what really sold us was the api that supported dynamic configuration. This would allow us to dynamically configure envoy to route to ingresses and clusters as they were created or destroyed.
To do this we built a tool called Yggdrasil using their Go sdk. Yggdrasil effectively just creates envoy configuration from Kubernetes ingress objects, so you point Yggdrasil at your kube clusters, it generates config from the ingresses and then envoy can loadbalance between your clusters for you. This is all done dynamically so as soon as new ingress is created the envoy nodes get updated with the new config. Importantly this all worked with what we already had, no need to create new config for every application, we just put this on top of it.
I use Envoy because it supports both http and http/2. It supports grpc and rest. It can even translates REST to Grpc. Best functionality i like from Envoy is it generates metrics which can be imported by Prometheus.