feat: gitea client

vendor/cloud.google.com/go/auth/grpctransport/directpath.go

@@ -0,0 +1,123 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package grpctransport
+
+import (
+	"context"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+
+	"cloud.google.com/go/auth"
+	"cloud.google.com/go/compute/metadata"
+	"google.golang.org/grpc"
+	grpcgoogle "google.golang.org/grpc/credentials/google"
+)
+
+func isDirectPathEnabled(endpoint string, opts *Options) bool {
+	if opts.InternalOptions != nil && !opts.InternalOptions.EnableDirectPath {
+		return false
+	}
+	if !checkDirectPathEndPoint(endpoint) {
+		return false
+	}
+	if b, _ := strconv.ParseBool(os.Getenv(disableDirectPathEnvVar)); b {
+		return false
+	}
+	return true
+}
+
+func checkDirectPathEndPoint(endpoint string) bool {
+	// Only [dns:///]host[:port] is supported, not other schemes (e.g., "tcp://" or "unix://").
+	// Also don't try direct path if the user has chosen an alternate name resolver
+	// (i.e., via ":///" prefix).
+	if strings.Contains(endpoint, "://") && !strings.HasPrefix(endpoint, "dns:///") {
+		return false
+	}
+
+	if endpoint == "" {
+		return false
+	}
+
+	return true
+}
+
+func isTokenProviderDirectPathCompatible(tp auth.TokenProvider, _ *Options) bool {
+	if tp == nil {
+		return false
+	}
+	tok, err := tp.Token(context.Background())
+	if err != nil {
+		return false
+	}
+	if tok == nil {
+		return false
+	}
+	if source, _ := tok.Metadata["auth.google.tokenSource"].(string); source != "compute-metadata" {
+		return false
+	}
+	if acct, _ := tok.Metadata["auth.google.serviceAccount"].(string); acct != "default" {
+		return false
+	}
+	return true
+}
+
+func isDirectPathXdsUsed(o *Options) bool {
+	// Method 1: Enable DirectPath xDS by env;
+	if b, _ := strconv.ParseBool(os.Getenv(enableDirectPathXdsEnvVar)); b {
+		return true
+	}
+	// Method 2: Enable DirectPath xDS by option;
+	if o.InternalOptions != nil && o.InternalOptions.EnableDirectPathXds {
+		return true
+	}
+	return false
+}
+
+// configureDirectPath returns some dial options and an endpoint to use if the
+// configuration allows the use of direct path. If it does not the provided
+// grpcOpts and endpoint are returned.
+func configureDirectPath(grpcOpts []grpc.DialOption, opts *Options, endpoint string, creds *auth.Credentials) ([]grpc.DialOption, string) {
+	if isDirectPathEnabled(endpoint, opts) && metadata.OnGCE() && isTokenProviderDirectPathCompatible(creds, opts) {
+		// Overwrite all of the previously specific DialOptions, DirectPath uses its own set of credentials and certificates.
+		grpcOpts = []grpc.DialOption{
+			grpc.WithCredentialsBundle(grpcgoogle.NewDefaultCredentialsWithOptions(grpcgoogle.DefaultCredentialsOptions{PerRPCCreds: &grpcCredentialsProvider{creds: creds}}))}
+		if timeoutDialerOption != nil {
+			grpcOpts = append(grpcOpts, timeoutDialerOption)
+		}
+		// Check if google-c2p resolver is enabled for DirectPath
+		if isDirectPathXdsUsed(opts) {
+			// google-c2p resolver target must not have a port number
+			if addr, _, err := net.SplitHostPort(endpoint); err == nil {
+				endpoint = "google-c2p:///" + addr
+			} else {
+				endpoint = "google-c2p:///" + endpoint
+			}
+		} else {
+			if !strings.HasPrefix(endpoint, "dns:///") {
+				endpoint = "dns:///" + endpoint
+			}
+			grpcOpts = append(grpcOpts,
+				// For now all DirectPath go clients will be using the following lb config, but in future
+				// when different services need different configs, then we should change this to a
+				// per-service config.
+				grpc.WithDisableServiceConfig(),
+				grpc.WithDefaultServiceConfig(`{"loadBalancingConfig":[{"grpclb":{"childPolicy":[{"pick_first":{}}]}}]}`))
+		}
+		// TODO: add support for system parameters (quota project, request reason) via chained interceptor.
+	}
+	return grpcOpts, endpoint
+}