Go Micro
Go Micro is a pluggable RPC based microservice library which provides the fundamental building blocks for writing distributed applications. It is part of the Micro toolchain. It supports Proto-RPC and JSON-RPC as the request/response protocol out of the box and defaults to Consul for discovery. Every aspect of go-micro is pluggable.
An example server can be found in examples/server.
Features
Feature | Package | Description |
---|---|---|
Discovery | Registry | A way of locating services to communicate with |
Client | Client | Used to make RPC requests to a service |
Codec | Client | Encoding/Decoding handler for requests |
Server | Server | Listens and serves RPC requests |
Pub/Sub | Broker | Publish and Subscribe to events |
Transport | Transport | Communication mechanism between services |
Prerequisites
Consul is the default discovery mechanism provided in go-micro. Discovery is however pluggable.
Install Consul
https://www.consul.io/intro/getting-started/install.html
Getting Started
Run Consul
$ consul agent -server -bootstrap-expect 1 -data-dir /tmp/consul
Run Service
$ go run examples/server/main.go --logtostderr
I1108 11:08:19.926071 11358 server.go:96] Starting server go.micro.srv.example id go.micro.srv.example-04de4cf0-8609-11e5-bf3a-68a86d0d36b6
I1108 11:08:19.926407 11358 rpc_server.go:233] Listening on [::]:54080
I1108 11:08:19.926500 11358 http_broker.go:80] Broker Listening on [::]:54081
I1108 11:08:19.926632 11358 rpc_server.go:158] Registering node: go.micro.srv.example-04de4cf0-8609-11e5-bf3a-68a86d0d36b6
Test Service
$ go run examples/client/main.go
go.micro.srv.example-59b6e0ab-0300-11e5-b696-68a86d0d36b6: Hello John
Writing a service
Create request/response proto
go-micro/examples/server/proto/example/example.proto
:
syntax = "proto3";
message Request {
string name = 1;
}
message Response {
string msg = 1;
}
Compile proto protoc -I$GOPATH/src --go_out=$GOPATH/src $GOPATH/src/github.com/micro/go-micro/examples/server/proto/example/example.proto
Create request handler
go-micro/examples/server/handler/example.go
:
package handler
import (
log "github.com/golang/glog"
c "github.com/micro/go-micro/context"
example "github.com/micro/go-micro/examples/server/proto/example"
"github.com/micro/go-micro/server"
"golang.org/x/net/context"
)
type Example struct{}
func (e *Example) Call(ctx context.Context, req *example.Request, rsp *example.Response) error {
md, _ := c.GetMetadata(ctx)
log.Infof("Received Example.Call request with metadata: %v", md)
rsp.Msg = server.Config().Id() + ": Hello " + req.Name
return nil
}
Init server
go-micro/examples/server/main.go
:
package main
import (
log "github.com/golang/glog"
"github.com/micro/go-micro/cmd"
"github.com/micro/go-micro/examples/server/handler"
"github.com/micro/go-micro/server"
)
func main() {
// optionally setup command line usage
cmd.Init()
// Initialise Server
server.Init(
server.Name("go.micro.srv.example"),
)
// Register Handlers
server.Handle(
server.NewHandler(
new(handler.Example),
),
)
// Run server
if err := server.Run(); err != nil {
log.Fatal(err)
}
}
Run service
$ go run examples/server/main.go --logtostderr
I1108 11:08:19.926071 11358 server.go:96] Starting server go.micro.srv.example id go.micro.srv.example-04de4cf0-8609-11e5-bf3a-68a86d0d36b6
I1108 11:08:19.926407 11358 rpc_server.go:233] Listening on [::]:54080
I1108 11:08:19.926500 11358 http_broker.go:80] Broker Listening on [::]:54081
I1108 11:08:19.926632 11358 rpc_server.go:158] Registering node: go.micro.srv.example-04de4cf0-8609-11e5-bf3a-68a86d0d36b6