mirror of
https://github.com/caddyserver/caddy.git
synced 2024-11-26 10:13:39 +08:00
109 lines
3.2 KiB
Go
109 lines
3.2 KiB
Go
package tracing
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"net/http"
|
|
|
|
"github.com/caddyserver/caddy/v2"
|
|
|
|
"github.com/caddyserver/caddy/v2/modules/caddyhttp"
|
|
"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
|
|
"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
|
|
"go.opentelemetry.io/otel/propagation"
|
|
"go.opentelemetry.io/otel/sdk/resource"
|
|
sdktrace "go.opentelemetry.io/otel/sdk/trace"
|
|
semconv "go.opentelemetry.io/otel/semconv/v1.7.0"
|
|
"go.uber.org/zap"
|
|
)
|
|
|
|
const (
|
|
webEngineName = "Caddy"
|
|
defaultSpanName = "handler"
|
|
nextCallCtxKey caddy.CtxKey = "nextCall"
|
|
)
|
|
|
|
// nextCall store the next handler, and the error value return on calling it (if any)
|
|
type nextCall struct {
|
|
next caddyhttp.Handler
|
|
err error
|
|
}
|
|
|
|
// openTelemetryWrapper is responsible for the tracing injection, extraction and propagation.
|
|
type openTelemetryWrapper struct {
|
|
propagators propagation.TextMapPropagator
|
|
|
|
handler http.Handler
|
|
|
|
spanName string
|
|
}
|
|
|
|
// newOpenTelemetryWrapper is responsible for the openTelemetryWrapper initialization using provided configuration.
|
|
func newOpenTelemetryWrapper(
|
|
ctx context.Context,
|
|
spanName string,
|
|
) (openTelemetryWrapper, error) {
|
|
if spanName == "" {
|
|
spanName = defaultSpanName
|
|
}
|
|
|
|
ot := openTelemetryWrapper{
|
|
spanName: spanName,
|
|
}
|
|
|
|
version, _ := caddy.Version()
|
|
res, err := ot.newResource(webEngineName, version)
|
|
if err != nil {
|
|
return ot, fmt.Errorf("creating resource error: %w", err)
|
|
}
|
|
|
|
traceExporter, err := otlptracegrpc.New(ctx)
|
|
if err != nil {
|
|
return ot, fmt.Errorf("creating trace exporter error: %w", err)
|
|
}
|
|
|
|
ot.propagators = propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{})
|
|
|
|
tracerProvider := globalTracerProvider.getTracerProvider(
|
|
sdktrace.WithBatcher(traceExporter),
|
|
sdktrace.WithResource(res),
|
|
)
|
|
|
|
ot.handler = otelhttp.NewHandler(http.HandlerFunc(ot.serveHTTP), ot.spanName, otelhttp.WithTracerProvider(tracerProvider), otelhttp.WithPropagators(ot.propagators))
|
|
return ot, nil
|
|
}
|
|
|
|
// serveHTTP injects a tracing context and call the next handler.
|
|
func (ot *openTelemetryWrapper) serveHTTP(w http.ResponseWriter, r *http.Request) {
|
|
ot.propagators.Inject(r.Context(), propagation.HeaderCarrier(r.Header))
|
|
next := r.Context().Value(nextCallCtxKey).(*nextCall)
|
|
next.err = next.next.ServeHTTP(w, r)
|
|
}
|
|
|
|
// ServeHTTP propagates call to the by wrapped by `otelhttp` next handler.
|
|
func (ot *openTelemetryWrapper) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
|
|
n := &nextCall{
|
|
next: next,
|
|
err: nil,
|
|
}
|
|
ot.handler.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), nextCallCtxKey, n)))
|
|
|
|
return n.err
|
|
}
|
|
|
|
// cleanup flush all remaining data and shutdown a tracerProvider
|
|
func (ot *openTelemetryWrapper) cleanup(logger *zap.Logger) error {
|
|
return globalTracerProvider.cleanupTracerProvider(logger)
|
|
}
|
|
|
|
// newResource creates a resource that describe current handler instance and merge it with a default attributes value.
|
|
func (ot *openTelemetryWrapper) newResource(
|
|
webEngineName,
|
|
webEngineVersion string,
|
|
) (*resource.Resource, error) {
|
|
return resource.Merge(resource.Default(), resource.NewSchemaless(
|
|
semconv.WebEngineNameKey.String(webEngineName),
|
|
semconv.WebEngineVersionKey.String(webEngineVersion),
|
|
))
|
|
}
|