micro/examples/service/wrapper/main.go

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package main
import (
"fmt"
"os"
"github.com/micro/cli"
"github.com/micro/go-micro"
"github.com/micro/go-micro/client"
proto "github.com/micro/go-micro/examples/service/proto"
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"github.com/micro/go-micro/metadata"
"github.com/micro/go-micro/server"
"golang.org/x/net/context"
)
/*
Example usage of top level service initialisation including wrappers
*/
type logWrapper struct {
client.Client
}
func (l *logWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
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md, _ := metadata.FromContext(ctx)
fmt.Printf("[Log Wrapper] ctx: %v service: %s method: %s\n", md, req.Service(), req.Method())
return l.Client.Call(ctx, req, rsp)
}
// Implements client.Wrapper as logWrapper
func logWrap(c client.Client) client.Client {
return &logWrapper{c}
}
// Implements the server.HandlerWrapper
func logHandlerWrapper(fn server.HandlerFunc) server.HandlerFunc {
return func(ctx context.Context, req server.Request, rsp interface{}) error {
fmt.Printf("[Log Wrapper] Before serving request method: %v\n", req.Method())
err := fn(ctx, req, rsp)
fmt.Println("[Log Wrapper] After serving request")
return err
}
}
type Greeter struct{}
func (g *Greeter) Hello(ctx context.Context, req *proto.HelloRequest, rsp *proto.HelloResponse) error {
rsp.Greeting = "Hello " + req.Name
return nil
}
// Setup and the client
func runClient(service micro.Service) {
// Create new greeter client
greeter := proto.NewGreeterClient("greeter", service.Client())
// Call the greeter
rsp, err := greeter.Hello(context.TODO(), &proto.HelloRequest{Name: "John"})
if err != nil {
fmt.Println(err)
return
}
// Print response
fmt.Println(rsp.Greeting)
}
func main() {
// Create a new service. Optionally include some options here.
service := micro.NewService(
micro.Client(client.NewClient(client.Wrap(logWrap))),
micro.Server(server.NewServer(server.WrapHandler(logHandlerWrapper))),
micro.Name("greeter"),
micro.Version("latest"),
micro.Metadata(map[string]string{
"type": "helloworld",
}),
// Setup some flags. Specify --run_client to run the client
// Add runtime flags
// We could do this below too
micro.Flags(cli.BoolFlag{
Name: "run_client",
Usage: "Launch the client",
}),
)
// Init will parse the command line flags. Any flags set will
// override the above settings. Options defined here will
// override anything set on the command line.
service.Init(
// Add runtime action
// We could actually do this above
micro.Action(func(c *cli.Context) {
if c.Bool("run_client") {
runClient(service)
os.Exit(0)
}
}),
)
// By default we'll run the server unless the flags catch us
// Setup the server
// Register handler
proto.RegisterGreeterHandler(service.Server(), new(Greeter))
// Run the server
if err := service.Run(); err != nil {
fmt.Println(err)
}
}