110 lines
3.2 KiB
Go
110 lines
3.2 KiB
Go
package main
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import (
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"flag"
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"net/http"
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"path"
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"strings"
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"github.com/golang/glog"
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"github.com/grpc-ecosystem/grpc-gateway/examples/examplepb"
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"github.com/grpc-ecosystem/grpc-gateway/runtime"
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"golang.org/x/net/context"
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"google.golang.org/grpc"
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)
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var (
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echoEndpoint = flag.String("echo_endpoint", "localhost:9090", "endpoint of EchoService")
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abeEndpoint = flag.String("more_endpoint", "localhost:9090", "endpoint of ABitOfEverythingService")
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flowEndpoint = flag.String("flow_endpoint", "localhost:9090", "endpoint of FlowCombination")
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swaggerDir = flag.String("swagger_dir", "examples/examplepb", "path to the directory which contains swagger definitions")
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)
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// newGateway returns a new gateway server which translates HTTP into gRPC.
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func newGateway(ctx context.Context, opts ...runtime.ServeMuxOption) (http.Handler, error) {
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mux := runtime.NewServeMux(opts...)
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dialOpts := []grpc.DialOption{grpc.WithInsecure()}
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err := examplepb.RegisterEchoServiceHandlerFromEndpoint(ctx, mux, *echoEndpoint, dialOpts)
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if err != nil {
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return nil, err
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}
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err = examplepb.RegisterStreamServiceHandlerFromEndpoint(ctx, mux, *abeEndpoint, dialOpts)
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if err != nil {
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return nil, err
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}
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err = examplepb.RegisterABitOfEverythingServiceHandlerFromEndpoint(ctx, mux, *abeEndpoint, dialOpts)
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if err != nil {
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return nil, err
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}
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err = examplepb.RegisterFlowCombinationHandlerFromEndpoint(ctx, mux, *flowEndpoint, dialOpts)
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if err != nil {
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return nil, err
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}
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return mux, nil
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}
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func serveSwagger(w http.ResponseWriter, r *http.Request) {
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if !strings.HasSuffix(r.URL.Path, ".swagger.json") {
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glog.Errorf("Not Found: %s", r.URL.Path)
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http.NotFound(w, r)
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return
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}
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glog.Infof("Serving %s", r.URL.Path)
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p := strings.TrimPrefix(r.URL.Path, "/swagger/")
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p = path.Join(*swaggerDir, p)
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http.ServeFile(w, r, p)
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}
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// allowCORS allows Cross Origin Resoruce Sharing from any origin.
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// Don't do this without consideration in production systems.
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func allowCORS(h http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if origin := r.Header.Get("Origin"); origin != "" {
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w.Header().Set("Access-Control-Allow-Origin", origin)
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if r.Method == "OPTIONS" && r.Header.Get("Access-Control-Request-Method") != "" {
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preflightHandler(w, r)
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return
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}
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}
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h.ServeHTTP(w, r)
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})
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}
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func preflightHandler(w http.ResponseWriter, r *http.Request) {
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headers := []string{"Content-Type", "Accept"}
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w.Header().Set("Access-Control-Allow-Headers", strings.Join(headers, ","))
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methods := []string{"GET", "HEAD", "POST", "PUT", "DELETE"}
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w.Header().Set("Access-Control-Allow-Methods", strings.Join(methods, ","))
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glog.Infof("preflight request for %s", r.URL.Path)
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return
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}
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// Run starts a HTTP server and blocks forever if successful.
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func Run(address string, opts ...runtime.ServeMuxOption) error {
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ctx := context.Background()
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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mux := http.NewServeMux()
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mux.HandleFunc("/swagger/", serveSwagger)
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gw, err := newGateway(ctx, opts...)
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if err != nil {
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return err
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}
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mux.Handle("/", gw)
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return http.ListenAndServe(address, allowCORS(mux))
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}
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func main() {
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flag.Parse()
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defer glog.Flush()
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if err := Run(":8080"); err != nil {
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glog.Fatal(err)
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}
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}
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