gRPC-Example

This repo is an example of using Go gRPC and tools from the greater gRPC ecosystem together with the GoGo Protobuf Project.

Installation

$ go get -u github.com/gogo/grpc-example

Running it

$ grpc-example
INFO: Serving gRPC on https://localhost:10000
INFO: parsed scheme: "passthrough"
INFO: ccResolverWrapper: sending new addresses to cc: [{localhost:10000 0  <nil>}]
INFO: ClientConn switching balancer to "pick_first"
INFO: pickfirstBalancer: HandleSubConnStateChange: 0xc420097cd0, CONNECTING
INFO: pickfirstBalancer: HandleSubConnStateChange: 0xc420097cd0, READY
INFO: Serving gRPC-Gateway on https://localhost:11000
INFO: Serving OpenAPI Documentation on https://localhost:11000/openapi-ui/

After starting the server, you can access the OpenAPI UI on https://localhost:11000/openapi-ui/

Development

To regenerate the proto files, ensure you have installed the generate dependencies:

$ GO111MODULE=on make install
go get \
        github.com/gogo/protobuf/protoc-gen-gogo \
        github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway \
        github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger \
        github.com/mwitkow/go-proto-validators/protoc-gen-govalidators \
        github.com/rakyll/statik
go: finding github.com/mwitkow/go-proto-validators/protoc-gen-govalidators latest
go: finding github.com/mwitkow/go-proto-validators latest
go: finding github.com/gogo/protobuf/protoc-gen-gogo latest
go: finding github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger latest
go: finding github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway latest

It also requires you to have the Google Protobuf compiler protoc installed. Please follow instructions for your platform on the official protoc repo.

Regenerate the files by running make generate:

$ make generate
# Generate gogo, gRPC-Gateway, swagger, go-validators output.
#
# -I declares import folders, in order of importance
# This is how proto resolves the protofile imports.
# It will check for the protofile relative to each of these
# folders and use the first one it finds.
#
# --gogo_out generates GoGo Protobuf output with gRPC plugin enabled.
# --grpc-gateway_out generates gRPC-Gateway output.
# --swagger_out generates an OpenAPI 2.0 specification for our gRPC-Gateway endpoints.
# --govalidators_out generates Go validation files for our messages types, if specified.
#
# The lines starting with Mgoogle/... are proto import replacements,
# which cause the generated file to import the specified packages
# instead of the go_package's declared by the imported protof files.
#
# $GOPATH/src is the output directory. It is relative to the GOPATH/src directory
# since we've specified a go_package option relative to that directory.
#
# proto/example.proto is the location of the protofile we use.
protoc \
        -I proto \
        -I vendor/github.com/grpc-ecosystem/grpc-gateway/ \
        -I vendor/github.com/gogo/googleapis/ \
        -I vendor/ \
        --gogo_out=plugins=grpc,\
Mgoogle/protobuf/timestamp.proto=github.com/gogo/protobuf/types,\
Mgoogle/protobuf/duration.proto=github.com/gogo/protobuf/types,\
Mgoogle/protobuf/empty.proto=github.com/gogo/protobuf/types,\
Mgoogle/api/annotations.proto=github.com/gogo/googleapis/google/api,\
Mgoogle/protobuf/field_mask.proto=github.com/gogo/protobuf/types:\
$GOPATH/src/ \
        --grpc-gateway_out=allow_patch_feature=false,\
Mgoogle/protobuf/timestamp.proto=github.com/gogo/protobuf/types,\
Mgoogle/protobuf/duration.proto=github.com/gogo/protobuf/types,\
Mgoogle/protobuf/empty.proto=github.com/gogo/protobuf/types,\
Mgoogle/api/annotations.proto=github.com/gogo/googleapis/google/api,\
Mgoogle/protobuf/field_mask.proto=github.com/gogo/protobuf/types:\
$GOPATH/src/ \
        --swagger_out=third_party/OpenAPI/ \
        --govalidators_out=gogoimport=true,\
Mgoogle/protobuf/timestamp.proto=github.com/gogo/protobuf/types,\
Mgoogle/protobuf/duration.proto=github.com/gogo/protobuf/types,\
Mgoogle/protobuf/empty.proto=github.com/gogo/protobuf/types,\
Mgoogle/api/annotations.proto=github.com/gogo/googleapis/google/api,\
Mgoogle/protobuf/field_mask.proto=github.com/gogo/protobuf/types:\
$GOPATH/src \
        proto/example.proto
# Workaround for https://github.com/grpc-ecosystem/grpc-gateway/issues/229.
sed -i.bak "s/empty.Empty/types.Empty/g" proto/example.pb.gw.go && rm proto/example.pb.gw.go.bak
# Generate static assets for OpenAPI UI
statik -m -f -src third_party/OpenAPI/