/
tracing.go
140 lines (118 loc) · 3.57 KB
/
tracing.go
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package turtleware
import (
"github.com/rs/zerolog"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/codes"
"go.opentelemetry.io/otel/propagation"
"go.opentelemetry.io/otel/trace"
"context"
"errors"
"fmt"
"net/http"
"strings"
)
const TracerName = "github.com/kernle32dll/turtleware"
// TracingTransport is an implementation of http.RoundTripper that will inject tracing information,
// and then call the actual Transport.
type TracingTransport struct {
tracer trace.TracerProvider
roundTripper http.RoundTripper
headerWhitelist map[string]struct{}
headerBlacklist map[string]struct{}
}
func NewTracingTransport(opts ...TracingOption) *TracingTransport {
// default
config := &tracingOptions{
tracer: nil,
roundTripper: nil,
headerWhitelist: nil,
headerBlacklist: nil,
}
// apply opts
for _, opt := range opts {
opt(config)
}
return &TracingTransport{
tracer: config.tracer,
roundTripper: config.roundTripper,
headerWhitelist: config.headerWhitelist,
headerBlacklist: config.headerBlacklist,
}
}
func (c TracingTransport) RoundTrip(req *http.Request) (*http.Response, error) {
tracerProvider := c.tracer
if tracerProvider == nil {
tracerProvider = otel.GetTracerProvider()
}
tracer := tracerProvider.Tracer(TracerName)
spanCtx, span := tracer.Start(req.Context(), fmt.Sprintf("HTTP %s: %s", req.Method, req.Host))
defer span.End()
span.SetAttributes(
attribute.String("http.url", req.URL.String()),
attribute.String("http.method", req.Method),
)
// Inject W3C trace context into request headers
propagation.TraceContext{}.Inject(
spanCtx,
propagation.HeaderCarrier(req.Header),
)
filteredHeaders := filterHeaders(req, c.headerWhitelist, c.headerBlacklist)
if len(filteredHeaders) > 0 {
for header, values := range filteredHeaders {
span.SetAttributes(attribute.StringSlice(
"header."+strings.ToLower(header), values,
))
}
}
roundTripper := c.roundTripper
if roundTripper == nil {
roundTripper = http.DefaultTransport
}
resp, err := roundTripper.RoundTrip(req)
if err != nil && !errors.Is(err, context.Canceled) && !errors.Is(err, context.DeadlineExceeded) {
span.SetStatus(codes.Error, err.Error())
span.RecordError(err)
}
if resp != nil {
span.SetAttributes(
attribute.Int("http.status_code", resp.StatusCode),
)
}
return resp, err
}
// WrapZerologTracing fetches the zerolog.Logger attached with the context
// (if existing), and creates a new logger with the context's spanID and
// traceID fields set.
func WrapZerologTracing(ctx context.Context) zerolog.Logger {
logger := *zerolog.Ctx(ctx)
// If there is no tracing data, we bail out directly
span := trace.SpanFromContext(ctx)
if span == nil {
return logger
}
spanContext := span.SpanContext()
if spanContext.HasTraceID() {
logger = logger.With().
Str("traceID", spanContext.TraceID().String()).
Logger()
}
if spanContext.HasSpanID() {
logger = logger.With().
Str("spanID", spanContext.SpanID().String()).
Logger()
}
return logger
}
// TagContextSpanWithError tries to retrieve an open telemetry span from the given
// context, and sets some error attributes, signaling that the current span
// has failed. If no span exists, this function does nothing.
// This function returns the error as provided, to facilitate easy error returning
// in using functions.
func TagContextSpanWithError(ctx context.Context, err error) error {
if span := trace.SpanFromContext(ctx); span != nil {
span.SetStatus(codes.Error, err.Error())
span.RecordError(err)
}
return err
}