72 lines
2.3 KiB
Go
72 lines
2.3 KiB
Go
package opentracing
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import (
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"net"
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"net/http"
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"strconv"
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"github.com/opentracing/opentracing-go"
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"github.com/opentracing/opentracing-go/ext"
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"golang.org/x/net/context"
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"github.com/go-kit/kit/log"
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kithttp "github.com/go-kit/kit/transport/http"
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)
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// ToHTTPRequest returns an http RequestFunc that injects an OpenTracing Span
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// found in `ctx` into the http headers. If no such Span can be found, the
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// RequestFunc is a noop.
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func ToHTTPRequest(tracer opentracing.Tracer, logger log.Logger) kithttp.RequestFunc {
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return func(ctx context.Context, req *http.Request) context.Context {
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// Try to find a Span in the Context.
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if span := opentracing.SpanFromContext(ctx); span != nil {
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// Add standard OpenTracing tags.
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ext.HTTPMethod.Set(span, req.Method)
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ext.HTTPUrl.Set(span, req.URL.String())
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host, portString, err := net.SplitHostPort(req.URL.Host)
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if err == nil {
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ext.PeerHostname.Set(span, host)
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if port, err := strconv.Atoi(portString); err != nil {
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ext.PeerPort.Set(span, uint16(port))
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}
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} else {
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ext.PeerHostname.Set(span, req.URL.Host)
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}
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// There's nothing we can do with any errors here.
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if err = tracer.Inject(
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span.Context(),
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opentracing.TextMap,
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opentracing.HTTPHeadersCarrier(req.Header),
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); err != nil {
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logger.Log("err", err)
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}
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}
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return ctx
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}
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}
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// FromHTTPRequest returns an http RequestFunc that tries to join with an
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// OpenTracing trace found in `req` and starts a new Span called
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// `operationName` accordingly. If no trace could be found in `req`, the Span
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// will be a trace root. The Span is incorporated in the returned Context and
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// can be retrieved with opentracing.SpanFromContext(ctx).
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func FromHTTPRequest(tracer opentracing.Tracer, operationName string, logger log.Logger) kithttp.RequestFunc {
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return func(ctx context.Context, req *http.Request) context.Context {
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// Try to join to a trace propagated in `req`.
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var span opentracing.Span
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wireContext, err := tracer.Extract(
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opentracing.TextMap,
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opentracing.HTTPHeadersCarrier(req.Header),
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)
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if err != nil && err != opentracing.ErrSpanContextNotFound {
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logger.Log("err", err)
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}
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span = tracer.StartSpan(operationName, ext.RPCServerOption(wireContext))
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ext.HTTPMethod.Set(span, req.Method)
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ext.HTTPUrl.Set(span, req.URL.String())
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return opentracing.ContextWithSpan(ctx, span)
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}
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}
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