From bde0377686e3cc5ef28a55b92800eb9d06bac0a4 Mon Sep 17 00:00:00 2001
From: Lukas Hering <lukasheringb@gmail.com>
Date: Fri, 26 Dec 2025 14:44:41 -0500
Subject: [PATCH] refactor: improve telemetry api receiver listener
 initialization logic

---
 .../receiver/telemetryapireceiver/factory.go  |  2 +-
 .../receiver/telemetryapireceiver/receiver.go | 59 ++++++++++++-------
 .../telemetryapireceiver/receiver_test.go     |  8 +--
 3 files changed, 43 insertions(+), 26 deletions(-)

diff --git a/collector/receiver/telemetryapireceiver/factory.go b/collector/receiver/telemetryapireceiver/factory.go
index b5ea6a3b13..01cfaf4d36 100644
--- a/collector/receiver/telemetryapireceiver/factory.go
+++ b/collector/receiver/telemetryapireceiver/factory.go
@@ -27,7 +27,7 @@ import (
 const (
 	typeStr     = "telemetryapi"
 	stability   = component.StabilityLevelDevelopment
-	defaultPort = 4325
+	defaultPort = 0
 	platform    = "platform"
 	function    = "function"
 	extension   = "extension"
diff --git a/collector/receiver/telemetryapireceiver/receiver.go b/collector/receiver/telemetryapireceiver/receiver.go
index 7b1f8b356a..43d97b0d96 100644
--- a/collector/receiver/telemetryapireceiver/receiver.go
+++ b/collector/receiver/telemetryapireceiver/receiver.go
@@ -18,11 +18,12 @@ import (
 	"context"
 	crand "crypto/rand"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
+	"net"
 	"net/http"
 	"os"
-	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -75,30 +76,52 @@ type telemetryAPIReceiver struct {
 	logReport               bool
 }
 
-func (r *telemetryAPIReceiver) Start(ctx context.Context, host component.Host) error {
-	address := listenOnAddress(r.port)
-	r.logger.Info("Listening for requests", zap.String("address", address))
+func (r *telemetryAPIReceiver) Start(ctx context.Context, _ component.Host) error {
+	if len(r.types) == 0 {
+		return fmt.Errorf("no telemetry event types provided")
+	}
+	listener, address, err := r.bindListener(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to bind listener: %w", err)
+	}
+	r.logger.Info("Starting telemetry API listener", zap.String("address", address))
 
 	mux := http.NewServeMux()
 	mux.HandleFunc("/", r.httpHandler)
 	r.httpServer = &http.Server{Addr: address, Handler: mux}
 	go func() {
-		_ = r.httpServer.ListenAndServe()
+		err := r.httpServer.Serve(listener)
+		if !errors.Is(err, http.ErrServerClosed) {
+			r.logger.Error("Telemetry API server stopped unexpectedly", zap.Error(err))
+		} else {
+			r.logger.Info("Telemetry API server stopped", zap.String("address", address))
+		}
 	}()
 
 	telemetryClient := telemetryapi.NewClient(r.logger)
-	if len(r.types) > 0 {
-		_, err := telemetryClient.Subscribe(ctx, r.types, r.extensionID, fmt.Sprintf("http://%s/", address))
-		if err != nil {
-			r.logger.Info("Listening for requests", zap.String("address", address), zap.String("extensionID", r.extensionID))
-			return err
-		}
+	if _, err := telemetryClient.Subscribe(ctx, r.types, r.extensionID, fmt.Sprintf("http://%s/", address)); err != nil {
+		r.logger.Error("Failed to subscribe to telemetry", zap.Error(err))
+		_ = r.Shutdown(ctx)
+		return err
 	}
+	r.logger.Info("Successfully subscribed to telemetry", zap.String("address", address))
 	return nil
 }
 
+func (r *telemetryAPIReceiver) bindListener(ctx context.Context) (net.Listener, string, error) {
+	listenerAddr := listenOnAddress()
+	var lc net.ListenConfig
+	l, err := lc.Listen(ctx, "tcp", fmt.Sprintf("%s:%d", listenerAddr, r.port))
+	if err != nil {
+		return nil, "", err
+	}
+	addr := fmt.Sprintf("%s:%d", l.Addr().Network(), l.Addr().(*net.TCPAddr).Port)
+	return l, addr, nil
+}
+
 func (r *telemetryAPIReceiver) Shutdown(ctx context.Context) error {
-	return nil
+	err := r.httpServer.Shutdown(ctx)
+	return err
 }
 
 func newSpanID() pcommon.SpanID {
@@ -192,9 +215,6 @@ func (r *telemetryAPIReceiver) httpHandler(w http.ResponseWriter, req *http.Requ
 			}
 		}
 	}
-
-	r.logger.Debug("logEvents received", zap.Int("count", len(slice)), zap.Int64("queue_length", r.queue.Len()))
-	slice = nil
 }
 
 func (r *telemetryAPIReceiver) getRecordRequestId(record map[string]interface{}) string {
@@ -534,14 +554,11 @@ func newTelemetryAPIReceiver(
 	}, nil
 }
 
-func listenOnAddress(port int) string {
+func listenOnAddress() string {
 	envAwsLocal, ok := os.LookupEnv("AWS_SAM_LOCAL")
-	var addr string
 	if ok && envAwsLocal == "true" {
-		addr = ":" + strconv.Itoa(port)
+		return ""
 	} else {
-		addr = "sandbox.localdomain:" + strconv.Itoa(port)
+		return "sandbox.localdomain"
 	}
-
-	return addr
 }
diff --git a/collector/receiver/telemetryapireceiver/receiver_test.go b/collector/receiver/telemetryapireceiver/receiver_test.go
index b3beafd2bd..1762579093 100644
--- a/collector/receiver/telemetryapireceiver/receiver_test.go
+++ b/collector/receiver/telemetryapireceiver/receiver_test.go
@@ -38,16 +38,16 @@ func TestListenOnAddress(t *testing.T) {
 		{
 			desc: "listen on address without AWS_SAM_LOCAL env variable",
 			testFunc: func(t *testing.T) {
-				addr := listenOnAddress(4325)
-				require.EqualValues(t, "sandbox.localdomain:4325", addr)
+				addr := listenOnAddress()
+				require.EqualValues(t, "sandbox.localdomain", addr)
 			},
 		},
 		{
 			desc: "listen on address with AWS_SAM_LOCAL env variable",
 			testFunc: func(t *testing.T) {
 				t.Setenv("AWS_SAM_LOCAL", "true")
-				addr := listenOnAddress(4325)
-				require.EqualValues(t, ":4325", addr)
+				addr := listenOnAddress()
+				require.EqualValues(t, "", addr)
 			},
 		},
 	}