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// Copyright 2017 Michal Witkowski. All Rights Reserved.
// See LICENSE for licensing terms.
package proxy_test
import (
"context"
"strings"
"gitlab.com/gitlab-org/gitaly/v14/internal/metadata"
"gitlab.com/gitlab-org/gitaly/v14/internal/praefect/grpc-proxy/proxy"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
grpc_metadata "google.golang.org/grpc/metadata"
"google.golang.org/grpc/status"
)
var director proxy.StreamDirector
func ExampleRegisterService() {
// A gRPC server with the proxying codec enabled.
server := grpc.NewServer(grpc.ForceServerCodec(proxy.NewCodec()))
// Register a TestService with 4 of its methods explicitly.
proxy.RegisterService(server, director,
"mwitkow.testproto.TestService",
"PingEmpty", "Ping", "PingError", "PingList")
}
func ExampleTransparentHandler() {
grpc.NewServer(
grpc.ForceServerCodec(proxy.NewCodec()),
grpc.UnknownServiceHandler(proxy.TransparentHandler(director)))
}
// Provide sa simple example of a director that shields internal services and dials a staging or production backend.
// This is a *very naive* implementation that creates a new connection on every request. Consider using pooling.
func ExampleStreamDirector() {
director = func(ctx context.Context, fullMethodName string, _ proxy.StreamPeeker) (*proxy.StreamParameters, error) {
// Make sure we never forward internal services.
if strings.HasPrefix(fullMethodName, "/com.example.internal.") {
return nil, status.Errorf(codes.Unimplemented, "Unknown method")
}
md, ok := grpc_metadata.FromIncomingContext(ctx)
if ok {
// Decide on which backend to dial
if val, exists := md[":authority"]; exists && val[0] == "staging.api.example.com" {
// Make sure we use DialContext so the dialing can be cancelled/time out together with the context.
conn, err := grpc.DialContext(ctx, "api-service.staging.svc.local", grpc.WithDefaultCallOptions(grpc.ForceCodec(proxy.NewCodec())))
return proxy.NewStreamParameters(proxy.Destination{
Conn: conn,
Ctx: metadata.IncomingToOutgoing(ctx),
}, nil, nil, nil), err
} else if val, exists := md[":authority"]; exists && val[0] == "api.example.com" {
conn, err := grpc.DialContext(ctx, "api-service.prod.svc.local", grpc.WithDefaultCallOptions(grpc.ForceCodec(proxy.NewCodec())))
return proxy.NewStreamParameters(proxy.Destination{
Conn: conn,
Ctx: metadata.IncomingToOutgoing(ctx),
}, nil, nil, nil), err
}
}
return nil, status.Errorf(codes.Unimplemented, "Unknown method")
}
}
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