| // Copyright 2017 Michal Witkowski. All Rights Reserved. |
| // See LICENSE for licensing terms. |
| |
| package grpc_ctxtags |
| |
| import ( |
| "github.com/grpc-ecosystem/go-grpc-middleware" |
| "golang.org/x/net/context" |
| "google.golang.org/grpc" |
| "google.golang.org/grpc/peer" |
| ) |
| |
| // UnaryServerInterceptor returns a new unary server interceptors that sets the values for request tags. |
| func UnaryServerInterceptor(opts ...Option) grpc.UnaryServerInterceptor { |
| o := evaluateOptions(opts) |
| return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) { |
| newCtx := newTagsForCtx(ctx) |
| if o.requestFieldsFunc != nil { |
| setRequestFieldTags(newCtx, o.requestFieldsFunc, info.FullMethod, req) |
| } |
| return handler(newCtx, req) |
| } |
| } |
| |
| // StreamServerInterceptor returns a new streaming server interceptor that sets the values for request tags. |
| func StreamServerInterceptor(opts ...Option) grpc.StreamServerInterceptor { |
| o := evaluateOptions(opts) |
| return func(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error { |
| newCtx := newTagsForCtx(stream.Context()) |
| if o.requestFieldsFunc == nil { |
| // Short-circuit, don't do the expensive bit of allocating a wrappedStream. |
| wrappedStream := grpc_middleware.WrapServerStream(stream) |
| wrappedStream.WrappedContext = newCtx |
| return handler(srv, wrappedStream) |
| } |
| wrapped := &wrappedStream{stream, info, o, newCtx, true} |
| err := handler(srv, wrapped) |
| return err |
| } |
| } |
| |
| // wrappedStream is a thin wrapper around grpc.ServerStream that allows modifying context and extracts log fields from the initial message. |
| type wrappedStream struct { |
| grpc.ServerStream |
| info *grpc.StreamServerInfo |
| opts *options |
| // WrappedContext is the wrapper's own Context. You can assign it. |
| WrappedContext context.Context |
| initial bool |
| } |
| |
| // Context returns the wrapper's WrappedContext, overwriting the nested grpc.ServerStream.Context() |
| func (w *wrappedStream) Context() context.Context { |
| return w.WrappedContext |
| } |
| |
| func (w *wrappedStream) RecvMsg(m interface{}) error { |
| err := w.ServerStream.RecvMsg(m) |
| // We only do log fields extraction on the single-request of a server-side stream. |
| if !w.info.IsClientStream || w.opts.requestFieldsFromInitial && w.initial { |
| w.initial = false |
| |
| setRequestFieldTags(w.Context(), w.opts.requestFieldsFunc, w.info.FullMethod, m) |
| } |
| return err |
| } |
| |
| func newTagsForCtx(ctx context.Context) context.Context { |
| t := newTags() |
| if peer, ok := peer.FromContext(ctx); ok { |
| t.Set("peer.address", peer.Addr.String()) |
| } |
| return setInContext(ctx, t) |
| } |
| |
| func setRequestFieldTags(ctx context.Context, f RequestFieldExtractorFunc, fullMethodName string, req interface{}) { |
| if valMap := f(fullMethodName, req); valMap != nil { |
| t := Extract(ctx) |
| for k, v := range valMap { |
| t.Set("grpc.request."+k, v) |
| } |
| } |
| } |