opentelemetry-collector/extension/zpagesextension/zpagesextension.go

124 lines
3.9 KiB
Go

// Copyright The OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package zpagesextension // import "go.opentelemetry.io/collector/extension/zpagesextension"
import (
"context"
"errors"
"net/http"
"path"
"go.opentelemetry.io/contrib/zpages"
"go.opentelemetry.io/otel/sdk/trace"
"go.uber.org/zap"
"go.opentelemetry.io/collector/component"
)
const (
tracezPath = "tracez"
)
type zpagesExtension struct {
config *Config
telemetry component.TelemetrySettings
zpagesSpanProcessor *zpages.SpanProcessor
server http.Server
stopCh chan struct{}
}
// registerableTracerProvider is a tracer that supports
// the SDK methods RegisterSpanProcessor and UnregisterSpanProcessor.
//
// We use an interface instead of casting to the SDK tracer type to support tracer providers
// that extend the SDK.
type registerableTracerProvider interface {
// RegisterSpanProcessor adds the given SpanProcessor to the list of SpanProcessors.
// https://pkg.go.dev/go.opentelemetry.io/otel/sdk/trace#TracerProvider.RegisterSpanProcessor.
RegisterSpanProcessor(SpanProcessor trace.SpanProcessor)
// UnregisterSpanProcessor removes the given SpanProcessor from the list of SpanProcessors.
// https://pkg.go.dev/go.opentelemetry.io/otel/sdk/trace#TracerProvider.UnregisterSpanProcessor.
UnregisterSpanProcessor(SpanProcessor trace.SpanProcessor)
}
func (zpe *zpagesExtension) Start(_ context.Context, host component.Host) error {
zPagesMux := http.NewServeMux()
sdktracer, ok := zpe.telemetry.TracerProvider.(registerableTracerProvider)
if ok {
sdktracer.RegisterSpanProcessor(zpe.zpagesSpanProcessor)
zPagesMux.Handle(path.Join("/debug", tracezPath), zpages.NewTracezHandler(zpe.zpagesSpanProcessor))
zpe.telemetry.Logger.Info("Registered zPages span processor on tracer provider")
} else {
zpe.telemetry.Logger.Warn("zPages span processor registration is not available")
}
hostZPages, ok := host.(interface {
RegisterZPages(mux *http.ServeMux, pathPrefix string)
})
if ok {
hostZPages.RegisterZPages(zPagesMux, "/debug")
zpe.telemetry.Logger.Info("Registered Host's zPages")
} else {
zpe.telemetry.Logger.Warn("Host's zPages not available")
}
// Start the listener here so we can have earlier failure if port is
// already in use.
ln, err := zpe.config.TCPAddr.Listen()
if err != nil {
return err
}
zpe.telemetry.Logger.Info("Starting zPages extension", zap.Any("config", zpe.config))
zpe.server = http.Server{Handler: zPagesMux}
zpe.stopCh = make(chan struct{})
go func() {
defer close(zpe.stopCh)
if errHTTP := zpe.server.Serve(ln); errHTTP != nil && !errors.Is(errHTTP, http.ErrServerClosed) {
host.ReportFatalError(errHTTP)
}
}()
return nil
}
func (zpe *zpagesExtension) Shutdown(context.Context) error {
err := zpe.server.Close()
if zpe.stopCh != nil {
<-zpe.stopCh
}
sdktracer, ok := zpe.telemetry.TracerProvider.(registerableTracerProvider)
if ok {
sdktracer.UnregisterSpanProcessor(zpe.zpagesSpanProcessor)
zpe.telemetry.Logger.Info("Unregistered zPages span processor on tracer provider")
} else {
zpe.telemetry.Logger.Warn("zPages span processor registration is not available")
}
return err
}
func newServer(config *Config, telemetry component.TelemetrySettings) *zpagesExtension {
return &zpagesExtension{
config: config,
telemetry: telemetry,
zpagesSpanProcessor: zpages.NewSpanProcessor(),
}
}