[service] fix: use ipv6-aware host and port concatenation function (#…

…10343)

#### Description
Fixing the bug: the latest version of otel-collector failed to start
with ipv6 metrics endpoint service telemetry.

This problem began to occur after
#9037 with
the feature gate flag enabled was merged. This problem is probably an
implementation omission because the enabled codepath, which was
originally added by
#7871, is
marked as WIP.

You can reproduce the issue with the config and the environment variable
(`MY_POD_IP=::1`).
```yaml
service:
  telemetry:
    logs:
      encoding: json
    metrics:
      address: '[${env:MY_POD_IP}]:8888'
```

#### Link to tracking issue
Fixes
#10011

---------

Co-authored-by: Tyler Helmuth <12352919+TylerHelmuth@users.noreply.github.com>

.chloggen/fix_ipv6_too_many_colon.yaml

@@ -0,0 +1,20 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: service
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fixed a bug that caused otel-collector to fail to start with ipv6 metrics endpoint service telemetry.
+
+# One or more tracking issues or pull requests related to the change
+issues: [10011]
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

internal/testutil/testutil.go

@@ -4,6 +4,7 @@
 package testutil // import "go.opentelemetry.io/collector/internal/testutil"
 
 import (
+	"fmt"
 	"net"
 	"os/exec"
 	"runtime"
@@ -31,15 +32,44 @@ func GetAvailableLocalAddress(t testing.TB) string {
 	// which do not show up under the "netstat -ano" but can only be found by
 	// "netsh interface ipv4 show excludedportrange protocol=tcp".  We'll use []exclusions to hold those ranges and
 	// retry if the port returned by GetAvailableLocalAddress falls in one of those them.
+	network := "tcp4"
 	var exclusions []portpair
 	portFound := false
 	if runtime.GOOS == "windows" {
-		exclusions = getExclusionsList(t)
+		exclusions = getExclusionsList(network, t)
 	}
 
 	var endpoint string
 	for !portFound {
-		endpoint = findAvailableAddress(t)
+		endpoint = findAvailableAddress(network, t)
+		_, port, err := net.SplitHostPort(endpoint)
+		require.NoError(t, err)
+		portFound = true
+		if runtime.GOOS == "windows" {
+			for _, pair := range exclusions {
+				if port >= pair.first && port <= pair.last {
+					portFound = false
+					break
+				}
+			}
+		}
+	}
+
+	return endpoint
+}
+
+// GetAvailableLocalIPv6Address is IPv6 version of GetAvailableLocalAddress.
+func GetAvailableLocalIPv6Address(t testing.TB) string {
+	network := "tcp6"
+	var exclusions []portpair
+	portFound := false
+	if runtime.GOOS == "windows" {
+		exclusions = getExclusionsList(network, t)
+	}
+
+	var endpoint string
+	for !portFound {
+		endpoint = findAvailableAddress(network, t)
 		_, port, err := net.SplitHostPort(endpoint)
 		require.NoError(t, err)
 		portFound = true
@@ -72,8 +102,17 @@ func GetAvailableLocalAddressPrometheus(t testing.TB) *config.Prometheus {
 	}
 }
 
-func findAvailableAddress(t testing.TB) string {
-	ln, err := net.Listen("tcp", "localhost:0")
+func findAvailableAddress(network string, t testing.TB) string {
+	var host string
+	switch network {
+	case "tcp", "tcp4":
+		host = "localhost"
+	case "tcp6":
+		host = "[::1]"
+	}
+	require.NotZero(t, host, "network must be either of tcp, tcp4 or tcp6")
+
+	ln, err := net.Listen("tcp", fmt.Sprintf("%s:0", host))
 	require.NoError(t, err, "Failed to get a free local port")
 	// There is a possible race if something else takes this same port before
 	// the test uses it, however, that is unlikely in practice.
@@ -84,8 +123,16 @@ func findAvailableAddress(t testing.TB) string {
 }
 
 // Get excluded ports on Windows from the command: netsh interface ipv4 show excludedportrange protocol=tcp
-func getExclusionsList(t testing.TB) []portpair {
-	cmdTCP := exec.Command("netsh", "interface", "ipv4", "show", "excludedportrange", "protocol=tcp")
+func getExclusionsList(network string, t testing.TB) []portpair {
+	var cmdTCP *exec.Cmd
+	switch network {
+	case "tcp", "tcp4":
+		cmdTCP = exec.Command("netsh", "interface", "ipv4", "show", "excludedportrange", "protocol=tcp")
+	case "tcp6":
+		cmdTCP = exec.Command("netsh", "interface", "ipv6", "show", "excludedportrange", "protocol=tcp")
+	}
+	require.NotZero(t, cmdTCP, "network must be either of tcp, tcp4 or tcp6")
+
 	outputTCP, errTCP := cmdTCP.CombinedOutput()
 	require.NoError(t, errTCP)
 	exclusions := createExclusionsList(string(outputTCP), t)

internal/testutil/testutil_test.go

@@ -29,14 +29,32 @@ func TestGetAvailableLocalAddress(t *testing.T) {
 	require.Nil(t, ln1)
 }
 
+func TestGetAvailableLocalIpv6Address(t *testing.T) {
+	endpoint := GetAvailableLocalIPv6Address(t)
+
+	// Endpoint should be free.
+	ln0, err := net.Listen("tcp", endpoint)
+	require.NoError(t, err)
+	require.NotNil(t, ln0)
+	t.Cleanup(func() {
+		assert.NoError(t, ln0.Close())
+	})
+
+	// Ensure that the endpoint wasn't something like ":0" by checking that a
+	// second listener will fail.
+	ln1, err := net.Listen("tcp", endpoint)
+	require.Error(t, err)
+	require.Nil(t, ln1)
+}
+
 func TestCreateExclusionsList(t *testing.T) {
 	// Test two examples of typical output from "netsh interface ipv4 show excludedportrange protocol=tcp"
 	emptyExclusionsText := `
 
 Protocol tcp Port Exclusion Ranges
 
-Start Port    End Port      
-----------    --------      
+Start Port    End Port
+----------    --------
 
 * - Administered port exclusions.`
 

service/internal/proctelemetry/config.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"net"
 	"net/http"
 	"net/url"
 	"os"
@@ -175,7 +176,7 @@ func initPrometheusExporter(prometheusConfig *config.Prometheus, asyncErrorChann
 		return nil, nil, fmt.Errorf("error creating otel prometheus exporter: %w", err)
 	}
 
-	return exporter, InitPrometheusServer(promRegistry, fmt.Sprintf("%s:%d", *prometheusConfig.Host, *prometheusConfig.Port), asyncErrorChannel), nil
+	return exporter, InitPrometheusServer(promRegistry, net.JoinHostPort(*prometheusConfig.Host, fmt.Sprintf("%d", *prometheusConfig.Port)), asyncErrorChannel), nil
 }
 
 func initPullExporter(exporter config.MetricExporter, asyncErrorChannel chan error) (sdkmetric.Reader, *http.Server, error) {

service/service_test.go

@@ -7,6 +7,7 @@ import (
 	"bufio"
 	"context"
 	"errors"
+	"fmt"
 	"net/http"
 	"strings"
 	"sync"
@@ -253,13 +254,16 @@ func TestServiceTelemetryCleanupOnError(t *testing.T) {
 
 func TestServiceTelemetry(t *testing.T) {
 	for _, tc := range ownMetricsTestCases() {
-		t.Run(tc.name, func(t *testing.T) {
-			testCollectorStartHelper(t, tc)
+		t.Run(fmt.Sprintf("ipv4_%s", tc.name), func(t *testing.T) {
+			testCollectorStartHelper(t, tc, "tcp4")
+		})
+		t.Run(fmt.Sprintf("ipv6_%s", tc.name), func(t *testing.T) {
+			testCollectorStartHelper(t, tc, "tcp6")
 		})
 	}
 }
 
-func testCollectorStartHelper(t *testing.T, tc ownMetricsTestCase) {
+func testCollectorStartHelper(t *testing.T, tc ownMetricsTestCase, network string) {
 	var once sync.Once
 	loggingHookCalled := false
 	hook := func(zapcore.Entry) error {
@@ -269,8 +273,20 @@ func testCollectorStartHelper(t *testing.T, tc ownMetricsTestCase) {
 		return nil
 	}
 
-	metricsAddr := testutil.GetAvailableLocalAddress(t)
-	zpagesAddr := testutil.GetAvailableLocalAddress(t)
+	var (
+		metricsAddr string
+		zpagesAddr  string
+	)
+	switch network {
+	case "tcp", "tcp4":
+		metricsAddr = testutil.GetAvailableLocalAddress(t)
+		zpagesAddr = testutil.GetAvailableLocalAddress(t)
+	case "tcp6":
+		metricsAddr = testutil.GetAvailableLocalIPv6Address(t)
+		zpagesAddr = testutil.GetAvailableLocalIPv6Address(t)
+	}
+	require.NotZero(t, metricsAddr, "network must be either of tcp, tcp4 or tcp6")
+	require.NotZero(t, zpagesAddr, "network must be either of tcp, tcp4 or tcp6")
 
 	set := newNopSettings()
 	set.BuildInfo = component.BuildInfo{Version: "test version", Command: otelCommand}