142 lines
5 KiB
Markdown
142 lines
5 KiB
Markdown
# gRPC-Go
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[](https://travis-ci.org/grpc/grpc-go)
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[](https://godoc.org/google.golang.org/grpc)
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[](https://goreportcard.com/report/github.com/grpc/grpc-go)
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The Go implementation of [gRPC](https://grpc.io/): A high performance, open
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source, general RPC framework that puts mobile and HTTP/2 first. For more
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information see the [gRPC Quick Start:
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Go](https://grpc.io/docs/languages/go/quickstart/) guide.
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Installation
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------------
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To install this package, you need to install Go and setup your Go workspace on
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your computer. The simplest way to install the library is to run:
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```
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$ go get -u google.golang.org/grpc
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```
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With Go module support (Go 1.11+), simply `import "google.golang.org/grpc"` in
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your source code and `go [build|run|test]` will automatically download the
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necessary dependencies ([Go modules
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ref](https://github.com/golang/go/wiki/Modules)).
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If you are trying to access grpc-go from within China, please see the
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[FAQ](#FAQ) below.
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Prerequisites
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-------------
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gRPC-Go officially supports the
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[three latest major releases of Go](https://golang.org/doc/devel/release.html).
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Documentation
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-------------
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- See [godoc](https://godoc.org/google.golang.org/grpc) for package and API
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descriptions.
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- Documentation on specific topics can be found in the [Documentation
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directory](Documentation/).
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- Examples can be found in the [examples directory](examples/).
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Performance
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-----------
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Performance benchmark data for grpc-go and other languages is maintained in
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[this
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dashboard](https://performance-dot-grpc-testing.appspot.com/explore?dashboard=5652536396611584&widget=490377658&container=1286539696).
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Status
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------
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General Availability [Google Cloud Platform Launch
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Stages](https://cloud.google.com/terms/launch-stages).
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FAQ
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---
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#### I/O Timeout Errors
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The `golang.org` domain may be blocked from some countries. `go get` usually
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produces an error like the following when this happens:
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```
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$ go get -u google.golang.org/grpc
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package google.golang.org/grpc: unrecognized import path "google.golang.org/grpc" (https fetch: Get https://google.golang.org/grpc?go-get=1: dial tcp 216.239.37.1:443: i/o timeout)
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```
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To build Go code, there are several options:
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- Set up a VPN and access google.golang.org through that.
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- Without Go module support: `git clone` the repo manually:
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```
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git clone https://github.com/grpc/grpc-go.git $GOPATH/src/google.golang.org/grpc
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```
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You will need to do the same for all of grpc's dependencies in `golang.org`,
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e.g. `golang.org/x/net`.
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- With Go module support: it is possible to use the `replace` feature of `go
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mod` to create aliases for golang.org packages. In your project's directory:
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```
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go mod edit -replace=google.golang.org/grpc=github.com/grpc/grpc-go@latest
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go mod tidy
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go mod vendor
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go build -mod=vendor
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```
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Again, this will need to be done for all transitive dependencies hosted on
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golang.org as well. Please refer to [this
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issue](https://github.com/golang/go/issues/28652) in the golang repo regarding
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this concern.
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#### Compiling error, undefined: grpc.SupportPackageIsVersion
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##### If you are using Go modules:
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Please ensure your gRPC-Go version is `require`d at the appropriate version in
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the same module containing the generated `.pb.go` files. For example,
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`SupportPackageIsVersion6` needs `v1.27.0`, so in your `go.mod` file:
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```
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module <your module name>
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require (
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google.golang.org/grpc v1.27.0
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)
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```
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##### If you are *not* using Go modules:
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Please update proto package, gRPC package and rebuild the proto files:
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- `go get -u github.com/golang/protobuf/{proto,protoc-gen-go}`
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- `go get -u google.golang.org/grpc`
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- `protoc --go_out=plugins=grpc:. *.proto`
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#### How to turn on logging
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The default logger is controlled by the environment variables. Turn everything
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on by setting:
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```
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GRPC_GO_LOG_VERBOSITY_LEVEL=99 GRPC_GO_LOG_SEVERITY_LEVEL=info
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```
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#### The RPC failed with error `"code = Unavailable desc = transport is closing"`
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This error means the connection the RPC is using was closed, and there are many
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possible reasons, including:
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1. mis-configured transport credentials, connection failed on handshaking
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1. bytes disrupted, possibly by a proxy in between
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1. server shutdown
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1. Keepalive parameters caused connection shutdown, for example if you have configured
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your server to terminate connections regularly to [trigger DNS lookups](https://github.com/grpc/grpc-go/issues/3170#issuecomment-552517779).
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If this is the case, you may want to increase your [MaxConnectionAgeGrace](https://pkg.go.dev/google.golang.org/grpc/keepalive?tab=doc#ServerParameters),
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to allow longer RPC calls to finish.
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It can be tricky to debug this because the error happens on the client side but
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the root cause of the connection being closed is on the server side. Turn on
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logging on __both client and server__, and see if there are any transport
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errors.
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