使用 Go to Cloud Run 实例的反向代理
我觉得我已经接近完成这项工作，但到目前为止，我遇到了一个问题，在 Go 中构建一个小型反向代理到 GCP Cloud Run 实例。请求“通过”，但请求的响应是默认的GCP Cloud Run 404。将请求返回到 Cloud Run 时会出现主机标头被忽略，因此请求没有被路由更正。
我可能在这里缺少什么？
package main
import (
"log"
"net/http"
"net/http/httputil"
"net/url"
)
const apiUrl = "MY_CLOUD_RUN.a.run.app"
func main() {
http.HandleFunc("/", proxy)
log.Fatal(http.ListenAndServe(":8081", nil))
}
func proxy(res http.ResponseWriter, req *http.Request) {
// gets past CORS checks
if req.Method == http.MethodOptions {
headers := res.Header()
headers.Add("Access-Control-Allow-Origin", "*")
headers.Add("Vary", "Origin")
headers.Add("Vary", "Access-Control-Request-Method")
headers.Add("Vary", "Access-Control-Request-Headers")
headers.Add("Access-Control-Allow-Headers", "*")
headers.Add("Access-Control-Allow-Methods", "GET,HEAD,PUT,PATCH,POST,DELETE")
res.WriteHeader(http.StatusOK)
return
}
p := httputil.NewSingleHostReverseProxy(&url.URL{
Scheme: "http",
Host: apiUrl,
})
p.Director = func(req *http.Request) {
req.Header.Add("X-Forwarded-Host", req.Host)
req.Header.Add("X-Origin-Host", apiUrl)
req.Header.Add("Host", apiUrl)
req.Header.Add("Access-Control-Allow-Origin", "*")
req.URL.Scheme = "https"
req.URL.Host = apiUrl
}
p.ModifyResponse = func(res *http.Response) error {
res.Header.Set("Access-Control-Allow-Methods", "GET,HEAD,PUT,PATCH,POST,DELETE")
res.Header.Set("Access-Control-Allow-Credentials", "true")
res.Header.Set("Access-Control-Allow-Origin", "*")
res.Header.Set("Access-Control-Allow-Headers", "*")
return nil
}
p.ServeHTTP(res, req)
}
慕仙森1回答
-
莫回无
这比最初的最初写的要复杂一些，但我们最终得到的结果如下。package mainimport ( "context" "fmt" "log" "net/http" "net/http/httputil" "net/url" "os" "os/signal" "time" "golang.org/x/oauth2" "google.golang.org/api/idtoken")var port = ":8080"var backend = "[CLOUD_RUN_INSTANCE_TO_PROXY].a.run.app"func main() { logger := log.New(os.Stdout, "proxy: ", log.LstdFlags) logger.Println(fmt.Sprintf("Proxy server is starting for: %s on port: %s", backend, port)) router := http.NewServeMux() router.Handle("/", proxyHandler()) server := &http.Server{ Addr: port, Handler: logging(logger)(router), ErrorLog: logger, ReadTimeout: 30 * time.Second, WriteTimeout: 30 * time.Second, IdleTimeout: 15 * time.Second, } done := make(chan bool) quit := make(chan os.Signal, 1) signal.Notify(quit, os.Interrupt) go func() { <-quit logger.Println("Proxy server is shutting down...") ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second) defer cancel() server.SetKeepAlivesEnabled(false) if err := server.Shutdown(ctx); err != nil { logger.Fatalf("Could not gracefully shutdown the server: %v\n", err) } close(done) }() if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed { logger.Fatalf("Could not listen on %s: %v\n", port, err) } <-done logger.Println("Server stopped")}func proxyHandler() http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { if r.Method == http.MethodOptions { headers := w.Header() headers.Add("Access-Control-Allow-Origin", "*") headers.Add("Access-Control-Allow-Headers", "*") headers.Add("Access-Control-Allow-Methods", "GET,HEAD,PUT,PATCH,POST,DELETE") w.WriteHeader(http.StatusOK) return } path := fmt.Sprintf("https://%s%s", backend, r.RequestURI) at, _ := idTokenTokenSource(path) p := httputil.NewSingleHostReverseProxy(&url.URL{ Scheme: "https", Host: backend, }) p.Director = func(r *http.Request) { if at != nil { at.SetAuthHeader(r) } } p.ModifyResponse = func(res *http.Response) error { res.Header.Set("Access-Control-Allow-Methods", "GET,HEAD,PUT,PATCH,POST,DELETE") res.Header.Set("Access-Control-Allow-Credentials", "true") res.Header.Set("Access-Control-Allow-Origin", "*") res.Header.Set("Access-Control-Allow-Headers", "*") return nil } r.URL.Scheme = "https" r.URL.Host = backend r.Header.Set("X-Forwarded-Host", r.Header.Get("Host")) r.Host = backend if at != nil { at.SetAuthHeader(r) } p.ServeHTTP(w, r) })}func logging(l *log.Logger) func(http.Handler) http.Handler { return func(next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { defer func() { requestId := r.Header.Get("X-Request-Id") if requestId == "" { requestId = fmt.Sprintf("%d", time.Now().UnixNano()) } w.Header().Set("X-Request-Id", requestId) l.Println(requestId, r.Method, r.URL.Path, r.RemoteAddr, r.UserAgent()) }() next.ServeHTTP(w, r) }) }}func idTokenTokenSource(audience string) (*oauth2.Token, error) { ts, err := idtoken.NewTokenSource(context.Background(), audience) if err != nil { return nil, err } t, err := ts.Token() if err != nil { return nil, err } return t, nil}一些正常关闭、http 设置和日志记录的很大一部分来自：https ://gist.github.com/enricofoltran/10b4a980cd07cb02836f70a4ab3e72d7
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