Go gRPC Middleware

gRPC Go Middleware: interceptors, helpers, utilities.

Important The repo recently moved to github.com/grpc-ecosystem/go-grpc-middleware, please update your import paths.

Middleware

gRPC Go recently acquired support for Interceptors, i.e. middleware that is executed either on the gRPC Server before the request is passed onto the user's application logic, or on the gRPC client either around the user call. It is a perfect way to implement common patterns: auth, logging, message, validation, retries or monitoring.

These are generic building blocks that make it easy to build multiple microservices easily. The purpose of this repository is to act as a go-to point for such reusable functionality. It contains some of them itself, but also will link to useful external repos.

grpc_middleware itself provides support for chaining interceptors. See Documentation, but here's an example:

import "github.com/grpc-ecosystem/go-grpc-middleware"

myServer := grpc.NewServer(
    grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(
        grpc_ctxtags.StreamServerInterceptor(),
        grpc_opentracing.StreamServerInterceptor(),
        grpc_prometheus.StreamServerInterceptor,
        grpc_zap.StreamServerInterceptor(zapLogger),
        grpc_auth.StreamServerInterceptor(myAuthFunction),
        grpc_recovery.StreamServerInterceptor(),
    )),
    grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(
        grpc_ctxtags.UnaryServerInterceptor(),
        grpc_opentracing.UnaryServerInterceptor(),
        grpc_prometheus.UnaryServerInterceptor,
        grpc_zap.UnaryServerInterceptor(zapLogger),
        grpc_auth.UnaryServerInterceptor(myAuthFunction),
        grpc_recovery.UnaryServerInterceptor(),
    )),
)

Interceptors

Please send a PR to add new interceptors or middleware to this list

Auth

grpc_auth - a customizable (via AuthFunc) piece of auth middleware

Logging

grpc_ctxtags - a library that adds a Tag map to context, with data populated from request body
grpc_zap - integration of zap logging library into gRPC handlers.
grpc_logrus - integration of logrus logging library into gRPC handlers.

Monitoring

grpc_prometheus⚡ - Prometheus client-side and server-side monitoring middleware
otgrpc⚡ - OpenTracing client-side and server-side interceptors
grpc_opentracing - OpenTracing client-side and server-side interceptors with support for streaming and handler-returned tags

Client

grpc_retry - a generic gRPC response code retry mechanism, client-side middleware

Server

grpc_validator - codegen inbound message validation from .proto options
grpc_recovery - turn panics into gRPC errors

Status

This code has been running in production since May 2016 as the basis of the gRPC micro services stack at Improbable.

Additional tooling will be added, and contributions are welcome.

License

go-grpc-middleware is released under the Apache 2.0 license. See the LICENSE file for details.

johanbrandhorst/go-grpc-middleware