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receiver.go
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receiver.go
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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
package webhookeventreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/webhookeventreceiver"
import (
"bufio"
"compress/gzip"
"context"
"errors"
"io"
"net/http"
"sync"
"time"
jsoniter "github.com/json-iterator/go"
"github.com/julienschmidt/httprouter"
"go.opentelemetry.io/collector/component"
"go.opentelemetry.io/collector/consumer"
"go.opentelemetry.io/collector/obsreport"
"go.opentelemetry.io/collector/receiver"
"go.uber.org/zap"
"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/webhookeventreceiver/internal/metadata"
)
var (
errNilLogsConsumer = errors.New("missing a logs consumer")
errMissingEndpoint = errors.New("missing a receiver endpoint")
errInvalidRequestMethod = errors.New("invalid method. Valid method is POST")
errInvalidEncodingType = errors.New("invalid encoding type")
errEmptyResponseBody = errors.New("request body content length is zero")
)
const healthyResponse = `{"text": "Webhookevent receiver is healthy"}`
type eventReceiver struct {
settings receiver.CreateSettings
cfg *Config
logConsumer consumer.Logs
server *http.Server
shutdownWG sync.WaitGroup
obsrecv *obsreport.Receiver
gzipPool *sync.Pool
}
func newLogsReceiver(params receiver.CreateSettings, cfg Config, consumer consumer.Logs) (receiver.Logs, error) {
if consumer == nil {
return nil, errNilLogsConsumer
}
if cfg.Endpoint == "" {
return nil, errMissingEndpoint
}
transport := "http"
if cfg.TLSSetting != nil {
transport = "https"
}
obsrecv, err := obsreport.NewReceiver(obsreport.ReceiverSettings{
ReceiverID: params.ID,
Transport: transport,
ReceiverCreateSettings: params,
})
if err != nil {
return nil, err
}
// create eventReceiver instance
er := &eventReceiver{
settings: params,
cfg: &cfg,
logConsumer: consumer,
obsrecv: obsrecv,
gzipPool: &sync.Pool{New: func() interface{} { return new(gzip.Reader) }},
}
return er, nil
}
// Start function manages receiver startup tasks. part of the receiver.Logs interface.
func (er *eventReceiver) Start(_ context.Context, host component.Host) error {
// noop if not nil. if start has not been called before these values should be nil.
if er.server != nil && er.server.Handler != nil {
return nil
}
// create listener from config
ln, err := er.cfg.HTTPServerSettings.ToListener()
if err != nil {
return err
}
// set up router.
router := httprouter.New()
router.POST(er.cfg.Path, er.handleReq)
router.GET(er.cfg.HealthPath, er.handleHealthCheck)
// webhook server standup and configuration
er.server, err = er.cfg.HTTPServerSettings.ToServer(host, er.settings.TelemetrySettings, router)
if err != nil {
return err
}
readTimeout, err := time.ParseDuration(er.cfg.ReadTimeout)
if err != nil {
return err
}
writeTimeout, err := time.ParseDuration(er.cfg.WriteTimeout)
if err != nil {
return err
}
// set timeouts
er.server.ReadHeaderTimeout = readTimeout
er.server.WriteTimeout = writeTimeout
// shutdown
er.shutdownWG.Add(1)
go func() {
defer er.shutdownWG.Done()
if errHTTP := er.server.Serve(ln); !errors.Is(errHTTP, http.ErrServerClosed) && errHTTP != nil {
host.ReportFatalError(errHTTP)
}
}()
return nil
}
// Shutdown function manages receiver shutdown tasks. part of the receiver.Logs interface.
func (er *eventReceiver) Shutdown(_ context.Context) error {
// server must exist to be closed.
if er.server == nil {
return nil
}
err := er.server.Close()
er.shutdownWG.Wait()
return err
}
// handleReq handles incoming request from webhook. On success returns a 200 response code to the webhook
func (er *eventReceiver) handleReq(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
ctx := r.Context()
ctx = er.obsrecv.StartLogsOp(ctx)
if r.Method != http.MethodPost {
er.failBadReq(ctx, w, http.StatusBadRequest, errInvalidRequestMethod)
return
}
encoding := r.Header.Get("Content-Encoding")
// only support gzip if encoding header is set.
if encoding != "" && encoding != "gzip" {
er.failBadReq(ctx, w, http.StatusUnsupportedMediaType, errInvalidEncodingType)
return
}
if r.ContentLength == 0 {
er.obsrecv.EndLogsOp(ctx, metadata.Type, 0, nil)
er.failBadReq(ctx, w, http.StatusBadRequest, errEmptyResponseBody)
}
bodyReader := r.Body
// gzip encoded case
if encoding == "gzip" || encoding == "x-gzip" {
reader := er.gzipPool.Get().(*gzip.Reader)
err := reader.Reset(bodyReader)
if err != nil {
er.failBadReq(ctx, w, http.StatusBadRequest, err)
_, _ = io.ReadAll(r.Body)
_ = r.Body.Close()
return
}
bodyReader = reader
defer er.gzipPool.Put(reader)
}
// finish reading the body into a log
sc := bufio.NewScanner(bodyReader)
ld, numLogs := reqToLog(sc, r.URL.Query(), er.cfg, er.settings)
consumerErr := er.logConsumer.ConsumeLogs(ctx, ld)
_ = bodyReader.Close()
if consumerErr != nil {
er.failBadReq(ctx, w, http.StatusInternalServerError, consumerErr)
er.obsrecv.EndLogsOp(ctx, metadata.Type, numLogs, nil)
} else {
w.WriteHeader(http.StatusOK)
er.obsrecv.EndLogsOp(ctx, metadata.Type, numLogs, nil)
}
}
// Simple healthcheck endpoint.
func (er *eventReceiver) handleHealthCheck(w http.ResponseWriter, _ *http.Request, _ httprouter.Params) {
w.Header().Add("Content-Type", "application/json")
w.WriteHeader(http.StatusOK)
_, _ = w.Write([]byte(healthyResponse))
}
// write response on a failed/bad request. Generates a small json body based on the thrown by
// the handle func and the appropriate http status code. many webhooks will either log these responses or
// notify webhook users should a none 2xx code be detected.
func (er *eventReceiver) failBadReq(_ context.Context,
w http.ResponseWriter,
httpStatusCode int,
err error) {
jsonResp, err := jsoniter.Marshal(err.Error())
if err != nil {
er.settings.Logger.Warn("failed to marshall error to json")
}
// write response to webhook
w.WriteHeader(httpStatusCode)
if len(jsonResp) > 0 {
w.Header().Add("Content-Type", "application/json")
_, err = w.Write(jsonResp)
if err != nil {
er.settings.Logger.Warn("failed to write json response", zap.Error(err))
}
}
// log bad webhook request if debug is enabled
if er.settings.Logger.Core().Enabled(zap.DebugLevel) {
msg := string(jsonResp)
er.settings.Logger.Debug(msg, zap.Int("http_status_code", httpStatusCode), zap.Error(err))
}
}