110 lines
2.8 KiB
Go
110 lines
2.8 KiB
Go
package tracing
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"io"
|
|
"net/http"
|
|
|
|
"github.com/opentracing-contrib/go-stdlib/nethttp"
|
|
opentracing "github.com/opentracing/opentracing-go"
|
|
"github.com/opentracing/opentracing-go/ext"
|
|
"github.com/opentracing/opentracing-go/log"
|
|
)
|
|
|
|
// StartSpan starts a new span as a child of the span in context.
|
|
// If there is no span in context then this is a no-op.
|
|
// The difference from opentracing.StartSpanFromContext is that this method
|
|
// does not depend on global tracer.
|
|
func StartSpan(ctx context.Context, operationName string, opts ...opentracing.StartSpanOption) (opentracing.Span, context.Context) {
|
|
parent := opentracing.SpanFromContext(ctx)
|
|
tracer := opentracing.Tracer(&opentracing.NoopTracer{})
|
|
if parent != nil {
|
|
tracer = parent.Tracer()
|
|
opts = append(opts, opentracing.ChildOf(parent.Context()))
|
|
}
|
|
span := tracer.StartSpan(operationName, opts...)
|
|
if parent != nil {
|
|
return span, opentracing.ContextWithSpan(ctx, span)
|
|
}
|
|
return span, ctx
|
|
}
|
|
|
|
// FinishWithError finalizes the span and sets the error if one is passed
|
|
func FinishWithError(span opentracing.Span, err error) {
|
|
if err != nil {
|
|
fields := []log.Field{
|
|
log.String("event", "error"),
|
|
log.String("message", err.Error()),
|
|
}
|
|
if _, ok := err.(interface {
|
|
Cause() error
|
|
}); ok {
|
|
fields = append(fields, log.String("stack", fmt.Sprintf("%+v", err)))
|
|
}
|
|
span.LogFields(fields...)
|
|
ext.Error.Set(span, true)
|
|
}
|
|
span.Finish()
|
|
}
|
|
|
|
// ContextWithSpanFromContext sets the tracing span of a context from other
|
|
// context if one is not already set. Alternative would be
|
|
// context.WithoutCancel() that would copy the context but reset ctx.Done
|
|
func ContextWithSpanFromContext(ctx, ctx2 context.Context) context.Context {
|
|
// if already is a span then noop
|
|
if span := opentracing.SpanFromContext(ctx); span != nil {
|
|
return ctx
|
|
}
|
|
if span := opentracing.SpanFromContext(ctx2); span != nil {
|
|
return opentracing.ContextWithSpan(ctx, span)
|
|
}
|
|
return ctx
|
|
}
|
|
|
|
var DefaultTransport http.RoundTripper = &Transport{
|
|
RoundTripper: &nethttp.Transport{RoundTripper: http.DefaultTransport},
|
|
}
|
|
|
|
var DefaultClient = &http.Client{
|
|
Transport: DefaultTransport,
|
|
}
|
|
|
|
type Transport struct {
|
|
http.RoundTripper
|
|
}
|
|
|
|
func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
|
|
span := opentracing.SpanFromContext(req.Context())
|
|
if span == nil { // no tracer connected with either request or transport
|
|
return t.RoundTripper.RoundTrip(req)
|
|
}
|
|
|
|
req, tracer := nethttp.TraceRequest(span.Tracer(), req)
|
|
|
|
resp, err := t.RoundTripper.RoundTrip(req)
|
|
if err != nil {
|
|
tracer.Finish()
|
|
return resp, err
|
|
}
|
|
|
|
if req.Method == "HEAD" {
|
|
tracer.Finish()
|
|
} else {
|
|
resp.Body = closeTracker{resp.Body, tracer.Finish}
|
|
}
|
|
|
|
return resp, err
|
|
}
|
|
|
|
type closeTracker struct {
|
|
io.ReadCloser
|
|
finish func()
|
|
}
|
|
|
|
func (c closeTracker) Close() error {
|
|
err := c.ReadCloser.Close()
|
|
c.finish()
|
|
return err
|
|
}
|