micro/util/wrapper/wrapper.go
2020-02-07 20:58:03 +00:00

135 lines
3.2 KiB
Go

package wrapper
import (
"context"
"strings"
"github.com/micro/go-micro/v2/client"
"github.com/micro/go-micro/v2/debug/stats"
"github.com/micro/go-micro/v2/debug/trace"
"github.com/micro/go-micro/v2/metadata"
"github.com/micro/go-micro/v2/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 {
// don't store traces for debug
if strings.HasPrefix(req.Endpoint(), "Debug.") {
return h(ctx, req, rsp)
}
// 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
}
}
}