package wrapper import ( "context" "github.com/micro/go-micro/client" "github.com/micro/go-micro/debug/stats" "github.com/micro/go-micro/debug/trace" "github.com/micro/go-micro/metadata" "github.com/micro/go-micro/server" ) type clientWrapper struct { client.Client headers metadata.Metadata } type traceWrapper struct { client.Client name string trace trace.Tracer } var ( HeaderPrefix = "Micro-" ) func (c *clientWrapper) setHeaders(ctx context.Context) context.Context { // copy metadata mda, _ := metadata.FromContext(ctx) md := metadata.Copy(mda) // set headers for k, v := range c.headers { if _, ok := md[k]; !ok { md[k] = v } } return metadata.NewContext(ctx, md) } func (c *clientWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error { ctx = c.setHeaders(ctx) return c.Client.Call(ctx, req, rsp, opts...) } func (c *clientWrapper) Stream(ctx context.Context, req client.Request, opts ...client.CallOption) (client.Stream, error) { ctx = c.setHeaders(ctx) return c.Client.Stream(ctx, req, opts...) } func (c *clientWrapper) Publish(ctx context.Context, p client.Message, opts ...client.PublishOption) error { ctx = c.setHeaders(ctx) return c.Client.Publish(ctx, p, opts...) } func (c *traceWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error { newCtx, s := c.trace.Start(ctx, req.Service()+"."+req.Endpoint()) err := c.Client.Call(newCtx, req, rsp, opts...) if err != nil { s.Metadata["error"] = err.Error() } // finish the trace c.trace.Finish(s) return err } // FromService wraps a client to inject From-Service header into metadata func FromService(name string, c client.Client) client.Client { return &clientWrapper{ c, metadata.Metadata{ HeaderPrefix + "From-Service": name, }, } } // HandlerStats wraps a server handler to generate request/error stats func HandlerStats(stats stats.Stats) server.HandlerWrapper { // return a handler wrapper return func(h server.HandlerFunc) server.HandlerFunc { // return a function that returns a function return func(ctx context.Context, req server.Request, rsp interface{}) error { // execute the handler err := h(ctx, req, rsp) // record the stats stats.Record(err) // return the error return err } } } // TraceCall is a call tracing wrapper func TraceCall(name string, t trace.Tracer, c client.Client) client.Client { return &traceWrapper{ name: name, trace: t, Client: c, } } // TraceHandler wraps a server handler to perform tracing func TraceHandler(t trace.Tracer) server.HandlerWrapper { // return a handler wrapper return func(h server.HandlerFunc) server.HandlerFunc { // return a function that returns a function return func(ctx context.Context, req server.Request, rsp interface{}) error { // get the span newCtx, s := t.Start(ctx, req.Service()+"."+req.Endpoint()) err := h(newCtx, req, rsp) if err != nil { s.Metadata["error"] = err.Error() } // finish t.Finish(s) return err } } }