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gateway.go
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gateway.go
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package grpc
import (
"context"
"crypto/tls"
"fmt"
"net/http"
"path"
"strings"
"github.com/go-openapi/runtime/middleware"
"github.com/grpc-ecosystem/grpc-gateway/runtime"
"github.com/jcmturner/gokrb5/v8/spnego"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/credentials/insecure"
protoutil "github.com/armadaproject/armada/internal/common/grpc/protoutils"
"github.com/armadaproject/armada/internal/common/util"
)
// CreateGatewayHandler configures the gRPC API gateway
// by registering relevant handlers with the given mux.
func CreateGatewayHandler(
grpcPort uint16,
mux *http.ServeMux,
apiBasePath string,
stripPrefix bool,
ssl bool,
corsAllowedOrigins []string,
spec string,
handlers ...func(ctx context.Context, mux *runtime.ServeMux, conn *grpc.ClientConn) error,
) (shutdown func()) {
connectionCtx, cancelConnectionCtx := context.WithCancel(context.Background())
grpcAddress := fmt.Sprintf(":%d", grpcPort)
m := new(protoutil.JSONMarshaller)
gw := runtime.NewServeMux(
runtime.WithMarshalerOption(runtime.MIMEWildcard, m),
runtime.WithOutgoingHeaderMatcher(func(key string) (string, bool) {
if key == strings.ToLower(spnego.HTTPHeaderAuthResponse) {
return spnego.HTTPHeaderAuthResponse, true
}
return fmt.Sprintf("%s%s", runtime.MetadataHeaderPrefix, key), true
}))
transportCreds := insecure.NewCredentials()
if ssl {
transportCreds = credentials.NewTLS(&tls.Config{InsecureSkipVerify: true})
}
conn, err := grpc.DialContext(connectionCtx, grpcAddress, grpc.WithTransportCredentials(transportCreds))
if err != nil {
panic(err)
}
// TODO this should return an error instead of calling panic
for _, handler := range handlers {
err = handler(connectionCtx, gw, conn)
if err != nil {
panic(err)
}
}
if stripPrefix {
prefixToStrip := strings.TrimSuffix(apiBasePath, "/")
mux.Handle(apiBasePath, http.StripPrefix(prefixToStrip, allowCORS(gw, corsAllowedOrigins)))
} else {
mux.Handle(apiBasePath, allowCORS(gw, corsAllowedOrigins))
}
mux.Handle(path.Join(apiBasePath, "swagger.json"), middleware.Spec(apiBasePath, []byte(spec), nil))
return func() {
cancelConnectionCtx()
conn.Close()
}
}
func allowCORS(h http.Handler, corsAllowedOrigins []string) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if origin := r.Header.Get("Origin"); origin != "" && util.ContainsString(corsAllowedOrigins, origin) {
w.Header().Set("Access-Control-Allow-Origin", origin)
w.Header().Set("Access-Control-Allow-Credentials", "true")
if r.Method == "OPTIONS" && r.Header.Get("Access-Control-Request-Method") != "" {
preflightHandler(w)
return
}
}
h.ServeHTTP(w, r)
})
}
func preflightHandler(w http.ResponseWriter) {
headers := []string{"Content-Type", "Accept", "Authorization"}
w.Header().Set("Access-Control-Allow-Headers", strings.Join(headers, ","))
methods := []string{"GET", "HEAD", "POST", "PUT", "DELETE"}
w.Header().Set("Access-Control-Allow-Methods", strings.Join(methods, ","))
}