69 lines
1.7 KiB
Go
69 lines
1.7 KiB
Go
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package http
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import (
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"errors"
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"fmt"
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"net/http"
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"os"
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"strconv"
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"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/ext"
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"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
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)
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const defaultResourceName = "http.request"
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type roundTripper struct {
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base http.RoundTripper
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cfg *roundTripperConfig
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}
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func (rt *roundTripper) RoundTrip(req *http.Request) (res *http.Response, err error) {
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span, _ := tracer.StartSpanFromContext(req.Context(), "http.request",
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tracer.SpanType(ext.SpanTypeHTTP),
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tracer.ResourceName(defaultResourceName),
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tracer.Tag(ext.HTTPMethod, req.Method),
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tracer.Tag(ext.HTTPURL, req.URL.Path),
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)
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defer func() {
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if rt.cfg.after != nil {
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rt.cfg.after(res, span)
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}
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span.Finish(tracer.WithError(err))
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}()
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if rt.cfg.before != nil {
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rt.cfg.before(req, span)
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}
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// inject the span context into the http request
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err = tracer.Inject(span.Context(), tracer.HTTPHeadersCarrier(req.Header))
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if err != nil {
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// this should never happen
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fmt.Fprintf(os.Stderr, "failed to inject http headers for round tripper: %v\n", err)
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}
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res, err = rt.base.RoundTrip(req)
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if err != nil {
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span.SetTag("http.errors", err.Error())
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} else {
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span.SetTag(ext.HTTPCode, strconv.Itoa(res.StatusCode))
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// treat 5XX as errors
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if res.StatusCode/100 == 5 {
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span.SetTag("http.errors", res.Status)
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err = errors.New(res.Status)
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}
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}
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return res, err
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}
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// WrapRoundTripper returns a new RoundTripper which traces all requests sent
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// over the transport.
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func WrapRoundTripper(rt http.RoundTripper, opts ...RoundTripperOption) http.RoundTripper {
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cfg := new(roundTripperConfig)
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for _, opt := range opts {
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opt(cfg)
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}
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return &roundTripper{
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base: rt,
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cfg: cfg,
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}
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}
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