1、 broker-service->auth-service->postgresdb；
2、 zipkin监控：需代码入侵；
使用 zipkin 库的 serverMiddleware，其通过 Http 跟踪（trace）链路。访问 auth-service，需通过 zipkinhttp.NewClient() 方法
zipkinhttp "github.com/openzipkin/zipkin-go/middleware/http"
一、broker-service
1、 通过Http传递span；
main.go
package main
import (
"log"
"net/http"
zipkinhttp "github.com/openzipkin/zipkin-go/middleware/http"
)
type Config struct{
}
const (
// Our service name.
serviceName = "auth"
// Host + port of our service.
hostPort = "localhost:8090"
// Endpoint to send Zipkin spans to.
zipkinHTTPEndpoint = "http://localhost:9411/api/v2/spans"
)
func main() {
tracer := GetTracer(serviceName, hostPort, zipkinHTTPEndpoint)
// create global zipkin http server middleware
serverMiddleware := zipkinhttp.NewServerMiddleware(
tracer, zipkinhttp.TagResponseSize(true),
)
// create global zipkin traced http client
client, err := zipkinhttp.NewClient(tracer, zipkinhttp.ClientTrace(true))
if err != nil {
log.Fatalf("unable to create client: %+v\n", err)
}
app := Config{
}
router := http.NewServeMux()
router.HandleFunc("/auth", app.Auth(client))
if err = http.ListenAndServe(":8080", serverMiddleware(router)); err != nil {
log.Panic(err)
}
}
1、 访问auth服务；
handler.go
package main
import (
"bytes"
"encoding/json"
"log"
"net/http"
"github.com/openzipkin/zipkin-go"
zipkinhttp "github.com/openzipkin/zipkin-go/middleware/http"
)
type AuthPayload struct {
Email string json:"email"
Password string json:"password"
}
func (app *Config) Auth(client *zipkinhttp.Client) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
log.Printf("auth service called with method: %s\n", r.Method)
// retrieve span from context (created by server middleware)
span := zipkin.SpanFromContext(r.Context())
defer span.Finish()
span.Tag("event", "authenticate")
var requestPayload AuthPayload
var payload jsonResponse
payload.Error = true
payload.Message = "Authentication failed!"
err := app.readJSON(w, r, &requestPayload)
if err != nil {
app.errorJSON(w, err)
return
}
// create json and send to the auth microservice
log.Println("authRequst: ", requestPayload)
jsonData, _ := json.Marshal(requestPayload)
url := "http://localhost:8090"
newRequest, err := http.NewRequest("POST", url+"/authenticate", bytes.NewBuffer(jsonData))
if err != nil {
log.Printf("unable to create client: %+v\n", err)
app.errorJSON(w, err, http.StatusBadRequest)
span.Tag("Error: ", err.Error())
return
}
newRequest.Header.Add("Content-type", "application/json")
ctx := zipkin.NewContext(newRequest.Context(), span)
newRequest = newRequest.WithContext(ctx)
resp, err := client.DoWithAppSpan(newRequest, "auth")
if err != nil {
log.Printf("call to auth returned error: %+v\n", err)
app.errorJSON(w, err, http.StatusBadGateway)
span.Tag("Error: ", err.Error())
return
}
defer resp.Body.Close()
err = json.NewDecoder(resp.Body).Decode(&payload)
if err != nil {
app.errorJSON(w, err, http.StatusBadGateway)
span.Tag("Error: ", err.Error())
return
}
app.writeJSON(w, http.StatusAccepted, payload)
}
}