README.md
1# Go gRPC Middleware
2
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11
12[gRPC Go](https://github.com/grpc/grpc-go) Middleware: interceptors, helpers, utilities.
13
14## Middleware
15
16[gRPC Go](https://github.com/grpc/grpc-go) recently acquired support for
17Interceptors, i.e. [middleware](https://medium.com/@matryer/writing-middleware-in-golang-and-how-go-makes-it-so-much-fun-4375c1246e81#.gv7tdlghs)
18that is executed either on the gRPC Server before the request is passed onto the user's application logic, or on the gRPC client around the user call. It is a perfect way to implement
19common patterns: auth, logging, message, validation, retries or monitoring.
20
21These are generic building blocks that make it easy to build multiple microservices easily.
22The purpose of this repository is to act as a go-to point for such reusable functionality. It contains
23some of them itself, but also will link to useful external repos.
24
25`grpc_middleware` itself provides support for chaining interceptors, here's an example:
26
27```go
28import "github.com/grpc-ecosystem/go-grpc-middleware"
29
30myServer := grpc.NewServer(
31 grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(
32 grpc_recovery.StreamServerInterceptor(),
33 grpc_ctxtags.StreamServerInterceptor(),
34 grpc_opentracing.StreamServerInterceptor(),
35 grpc_prometheus.StreamServerInterceptor,
36 grpc_zap.StreamServerInterceptor(zapLogger),
37 grpc_auth.StreamServerInterceptor(myAuthFunction),
38 )),
39 grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(
40 grpc_recovery.UnaryServerInterceptor(),
41 grpc_ctxtags.UnaryServerInterceptor(),
42 grpc_opentracing.UnaryServerInterceptor(),
43 grpc_prometheus.UnaryServerInterceptor,
44 grpc_zap.UnaryServerInterceptor(zapLogger),
45 grpc_auth.UnaryServerInterceptor(myAuthFunction),
46 )),
47)
48```
49
50## Interceptors
51
52*Please send a PR to add new interceptors or middleware to this list*
53
54#### Auth
55 * [`grpc_auth`](auth) - a customizable (via `AuthFunc`) piece of auth middleware
56
57#### Logging
58 * [`grpc_ctxtags`](tags/) - a library that adds a `Tag` map to context, with data populated from request body
59 * [`grpc_zap`](logging/zap/) - integration of [zap](https://github.com/uber-go/zap) logging library into gRPC handlers.
60 * [`grpc_logrus`](logging/logrus/) - integration of [logrus](https://github.com/sirupsen/logrus) logging library into gRPC handlers.
61 * [`grpc_kit`](logging/kit/) - integration of [go-kit](https://github.com/go-kit/kit/tree/master/log) logging library into gRPC handlers.
62 * [`grpc_grpc_logsettable`](logging/settable/) - a wrapper around `grpclog.LoggerV2` that allows to replace loggers in runtime (thread-safe).
63
64#### Monitoring
65 * [`grpc_prometheus`⚡](https://github.com/grpc-ecosystem/go-grpc-prometheus) - Prometheus client-side and server-side monitoring middleware
66 * [`otgrpc`⚡](https://github.com/grpc-ecosystem/grpc-opentracing/tree/master/go/otgrpc) - [OpenTracing](http://opentracing.io/) client-side and server-side interceptors
67 * [`grpc_opentracing`](tracing/opentracing) - [OpenTracing](http://opentracing.io/) client-side and server-side interceptors with support for streaming and handler-returned tags
68
69#### Client
70 * [`grpc_retry`](retry/) - a generic gRPC response code retry mechanism, client-side middleware
71
72#### Server
73 * [`grpc_validator`](validator/) - codegen inbound message validation from `.proto` options
74 * [`grpc_recovery`](recovery/) - turn panics into gRPC errors
75 * [`ratelimit`](ratelimit/) - grpc rate limiting by your own limiter
76
77
78## Status
79
80This code has been running in *production* since May 2016 as the basis of the gRPC micro services stack at [Improbable](https://improbable.io).
81
82Additional tooling will be added, and contributions are welcome.
83
84## License
85
86`go-grpc-middleware` is released under the Apache 2.0 license. See the [LICENSE](LICENSE) file for details.
87