Add integration test for sock_iter pre-existing socket tracking

internal/test/integration/components/keepaliveclient/Dockerfile

@@ -0,0 +1,24 @@
+FROM golang:1.25.7@sha256:85c0ab0b73087fda36bf8692efe2cf67c54a06d7ca3b49c489bbff98c9954d64 AS builder
+
+ARG TARGETARCH
+
+ENV GOARCH=$TARGETARCH
+
+WORKDIR /src
+
+COPY internal/test/ internal/test/
+COPY go.mod go.mod
+COPY go.sum go.sum
+
+RUN go build -o keepaliveclient ./internal/test/integration/components/keepaliveclient/
+
+FROM debian:bookworm-slim@sha256:98f4b71de414932439ac6ac690d7060df1f27161073c5036a7553723881bffbe
+
+WORKDIR /
+
+COPY --from=builder /src/keepaliveclient .
+USER 0:0
+
+HEALTHCHECK --interval=1s --retries=15 CMD test -f /tmp/connected
+
+CMD [ "/keepaliveclient" ]

internal/test/integration/components/keepaliveclient/main.go

@@ -0,0 +1,73 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"sync/atomic"
+	"time"
+)
+
+var traceparentSeen atomic.Bool
+
+func main() {
+	transport := &http.Transport{
+		MaxIdleConns:        1,
+		MaxIdleConnsPerHost: 1,
+		MaxConnsPerHost:     1,
+		IdleConnTimeout:     30 * time.Second,
+		DisableKeepAlives:   false,
+		ForceAttemptHTTP2:   false,
+	}
+
+	transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+		conn, err := (&net.Dialer{}).DialContext(ctx, network, addr)
+		if err != nil {
+			return nil, err
+		}
+		if err := os.WriteFile("/tmp/connected", nil, 0o600); err != nil {
+			log.Printf("failed to write /tmp/connected: %v", err)
+		}
+		return conn, nil
+	}
+
+	client := &http.Client{
+		Transport: transport,
+		Timeout:   10 * time.Second,
+	}
+
+	go func() {
+		http.HandleFunc("/status", func(w http.ResponseWriter, _ *http.Request) {
+			if traceparentSeen.Load() {
+				w.WriteHeader(http.StatusOK)
+			} else {
+				w.WriteHeader(http.StatusNoContent)
+			}
+		})
+		log.Fatal(http.ListenAndServe(":9091", nil))
+	}()
+
+	for {
+		resp, err := client.Get("http://tpinjector-server:8080/smoke-echo")
+		if err != nil {
+			log.Printf("request failed: %v", err)
+			time.Sleep(time.Second)
+			continue
+		}
+		resp.Body.Close()
+
+		if tp := resp.Header.Get("X-Received-Traceparent"); tp != "" {
+			if traceparentSeen.CompareAndSwap(false, true) {
+				fmt.Printf("traceparent received by server: %s\n", tp)
+			}
+		}
+
+		time.Sleep(time.Second)
+	}
+}

internal/test/integration/components/tpinjector-server/Dockerfile

@@ -0,0 +1,22 @@
+FROM golang:1.25.7@sha256:85c0ab0b73087fda36bf8692efe2cf67c54a06d7ca3b49c489bbff98c9954d64 AS builder
+
+ARG TARGETARCH
+
+ENV GOARCH=$TARGETARCH
+
+WORKDIR /src
+
+COPY internal/test/ internal/test/
+COPY go.mod go.mod
+COPY go.sum go.sum
+
+RUN go build -o tpinjector-server ./internal/test/integration/components/tpinjector-server/
+
+FROM debian:bookworm-slim@sha256:98f4b71de414932439ac6ac690d7060df1f27161073c5036a7553723881bffbe
+
+WORKDIR /
+
+COPY --from=builder /src/tpinjector-server .
+USER 0:0
+
+CMD [ "/tpinjector-server" ]

internal/test/integration/components/tpinjector-server/main.go

@@ -0,0 +1,24 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package main
+
+import (
+	"log"
+	"net/http"
+)
+
+func main() {
+	http.HandleFunc("/smoke", func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	})
+
+	http.HandleFunc("/smoke-echo", func(w http.ResponseWriter, r *http.Request) {
+		if tp := r.Header.Get("Traceparent"); tp != "" {
+			w.Header().Set("X-Received-Traceparent", tp)
+		}
+		w.WriteHeader(http.StatusOK)
+	})
+
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}

internal/test/integration/configs/obi-config-keepalive.yml

@@ -0,0 +1,14 @@
+trace_printer: text
+log_level: debug
+routes:
+  unmatched: path
+ebpf:
+  context_propagation: headers
+  bpf_debug: true
+discovery:
+  skip_go_specific_tracers: true
+  services:
+    - name: keepaliveclient
+      exe_path: keepaliveclient
+    - name: tpinjector-server
+      exe_path: tpinjector-server

internal/test/integration/docker-compose-keepalive.yml

@@ -0,0 +1,46 @@
+version: "3.8"
+
+services:
+  tpinjector-server:
+    build:
+      context: ../../..
+      dockerfile: internal/test/integration/components/tpinjector-server/Dockerfile
+    image: hatest-tpinjector-server
+    ports:
+      - "8080:8080"
+
+  keepaliveclient:
+    build:
+      context: ../../..
+      dockerfile: internal/test/integration/components/keepaliveclient/Dockerfile
+    image: hatest-keepaliveclient
+    ports:
+      - "9091:9091"
+    depends_on:
+      tpinjector-server:
+        condition: service_started
+    healthcheck:
+      test: ["CMD", "test", "-f", "/tmp/connected"]
+      interval: 1s
+      retries: 15
+
+  obi:
+    build:
+      context: ../../..
+      dockerfile: ./internal/test/integration/components/obi/Dockerfile
+    command:
+      - --config=/configs/obi-config-keepalive.yml
+    volumes:
+      - ./configs/:/configs
+      - ./system/sys/kernel/security:/sys/kernel/security
+      - ../../../testoutput:/coverage
+      - ../../../testoutput/run-keepalive:/var/run/obi
+    image: hatest-obi
+    privileged: true
+    pid: "host"
+    network_mode: "service:keepaliveclient"
+    environment:
+      GOCOVERDIR: "/coverage"
+    depends_on:
+      keepaliveclient:
+        condition: service_healthy

internal/test/integration/keepalive_test.go

@@ -0,0 +1,35 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build integration
+
+package integration
+
+import (
+	"net/http"
+	"path"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.opentelemetry.io/obi/internal/test/integration/components/docker"
+)
+
+func TestExistingSocketsDetection(t *testing.T) {
+	compose, err := docker.ComposeSuite("docker-compose-keepalive.yml", path.Join(pathOutput, "test-suite-keepalive.log"))
+	require.NoError(t, err)
+	require.NoError(t, compose.Up())
+
+	waitForTestComponentsNoMetrics(t, "http://localhost:8080/smoke")
+
+	require.EventuallyWithT(t, func(ct *assert.CollectT) {
+		resp, err := http.Get("http://localhost:9091/status")
+		require.NoError(ct, err)
+		resp.Body.Close()
+		require.Equal(ct, http.StatusOK, resp.StatusCode)
+	}, testTimeout, time.Second)
+
+	require.NoError(t, compose.Close())
+}