[cmd/opampsupervisor] Fix windows support (#34573)

**Description:** <Describe what has changed.>
* Fixed windows improper signalling for the agent to shutdown.
* Fixed not closing files in e2e tests (windows will error if a file is
not closed when it attempts to delete the temp directory said file is
in)
* Fixed test config templates quoting (windows filepaths would have
trouble since the backslash acts like a character escape)
* Added a workflow to allow running e2e tests for windows

**Link to tracking Issue:** Closes #34570

**Testing:** 
* Existing e2e tests cover this.
* I've manually tested remotely configuring a windows supervisor with
BindPlane.

---------

Co-authored-by: Daniel Jaglowski <jaglows3@gmail.com>

.chloggen/fix_supervisor-windows-signalling.yaml

@@ -0,0 +1,13 @@
+# 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. filelogreceiver)
+component: cmd/opampsupervisor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Fix supervisor support for Windows."
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [34570]

.github/workflows/e2e-tests-windows.yml

@@ -0,0 +1,82 @@
+name: e2e-tests-windows
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - "v[0-9]+.[0-9]+.[0-9]+*"
+    paths-ignore:
+      - "**/README.md"
+  pull_request:
+    paths-ignore:
+      - "**/README.md"
+  merge_group:
+
+env:
+  # Make sure to exit early if cache segment download times out after 2 minutes.
+  # We limit cache download as a whole to 5 minutes.
+  SEGMENT_DOWNLOAD_TIMEOUT_MINS: 2
+
+jobs:
+  collector-build:
+    runs-on: windows-latest
+    if: ${{ github.actor != 'dependabot[bot]' && (contains(github.event.pull_request.labels.*.name, 'Run Windows') || github.event_name == 'push' || github.event_name == 'merge_group') }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: "1.21.12"
+          cache: false
+      - name: Cache Go
+        id: go-mod-cache
+        timeout-minutes: 25
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~\go\pkg\mod
+            ~\AppData\Local\go-build
+          key: go-build-cache-${{ runner.os }}-${{ matrix.group }}-go-${{ hashFiles('**/go.sum') }}
+      - name: Install dependencies
+        if: steps.go-mod-cache.outputs.cache-hit != 'true'
+        run: make -j2 gomoddownload
+      - name: Build Collector
+        run: make otelcontribcol
+      - name: Upload Collector Binary
+        uses: actions/upload-artifact@v4
+        with:
+          name: collector-binary
+          path: ./bin/*
+
+  supervisor-test:
+    runs-on: windows-latest
+    if: ${{ github.actor != 'dependabot[bot]' && (contains(github.event.pull_request.labels.*.name, 'Run Windows') || github.event_name == 'push' || github.event_name == 'merge_group') }}
+    needs: [collector-build]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: "1.21.12"
+          cache: false
+      - name: Cache Go
+        id: go-mod-cache
+        timeout-minutes: 25
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~\go\pkg\mod
+            ~\AppData\Local\go-build
+          key: go-build-cache-${{ runner.os }}-${{ matrix.group }}-go-${{ hashFiles('**/go.sum') }}
+      - name: Install dependencies
+        if: steps.go-mod-cache.outputs.cache-hit != 'true'
+        run: make -j2 gomoddownload
+      - name: Download Collector Binary
+        uses: actions/download-artifact@v4
+        with:
+          name: collector-binary
+          path: bin/
+      - name: Run opampsupervisor e2e tests
+        run: |
+          cd cmd/opampsupervisor
+          go test -v --tags=e2e

cmd/opampsupervisor/e2e_test.go

@@ -172,6 +172,7 @@ func getSupervisorConfig(t *testing.T, configType string, extraConfigData map[st
 	if runtime.GOOS == "windows" {
 		extension = ".exe"
 	}
+
 	configData := map[string]string{
 		"goos":        runtime.GOOS,
 		"goarch":      runtime.GOARCH,
@@ -184,7 +185,10 @@ func getSupervisorConfig(t *testing.T, configType string, extraConfigData map[st
 	}
 	err = templ.Execute(&buf, configData)
 	require.NoError(t, err)
-	cfgFile, _ := os.CreateTemp(t.TempDir(), "config_*.yaml")
+	cfgFile, err := os.CreateTemp(t.TempDir(), "config_*.yaml")
+	require.NoError(t, err)
+	t.Cleanup(func() { cfgFile.Close() })
+
 	_, err = cfgFile.Write(buf.Bytes())
 	require.NoError(t, err)
 
@@ -617,11 +621,13 @@ func TestSupervisorReportsEffectiveConfig(t *testing.T) {
 	tempDir := t.TempDir()
 	testKeyFile, err := os.CreateTemp(tempDir, "confKey")
 	require.NoError(t, err)
+	t.Cleanup(func() { testKeyFile.Close() })
+
 	n, err := testKeyFile.Write([]byte(testKeyFile.Name()))
 	require.NoError(t, err)
 	require.NotZero(t, n)
 
-	colCfgTpl, err := os.ReadFile(path.Join("testdata", "collector", "split_config.yaml"))
+	colCfgTpl, err := os.ReadFile(filepath.Join("testdata", "collector", "split_config.yaml"))
 	require.NoError(t, err)
 
 	templ, err := template.New("").Parse(string(colCfgTpl))
@@ -770,9 +776,11 @@ func createSimplePipelineCollectorConf(t *testing.T) (*bytes.Buffer, []byte, *os
 	tempDir := t.TempDir()
 	inputFile, err := os.CreateTemp(tempDir, "input_*.yaml")
 	require.NoError(t, err)
+	t.Cleanup(func() { inputFile.Close() })
 
 	outputFile, err := os.CreateTemp(tempDir, "output_*.yaml")
 	require.NoError(t, err)
+	t.Cleanup(func() { outputFile.Close() })
 
 	colCfgTpl, err := os.ReadFile(path.Join(wd, "testdata", "collector", "simple_pipeline.yaml"))
 	require.NoError(t, err)

cmd/opampsupervisor/go.mod

@@ -17,6 +17,7 @@ require (
 	go.opentelemetry.io/collector/semconv v0.107.1-0.20240816132030-9fd84668bb02
 	go.uber.org/goleak v1.3.0
 	go.uber.org/zap v1.27.0
+	golang.org/x/sys v0.21.0
 	google.golang.org/protobuf v1.34.2
 	gopkg.in/yaml.v3 v3.0.1
 )
@@ -32,5 +33,4 @@ require (
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/net v0.23.0 // indirect
-	golang.org/x/sys v0.21.0 // indirect
 )

cmd/opampsupervisor/supervisor/commander/commander.go

@@ -11,7 +11,6 @@ import (
 	"os/exec"
 	"path/filepath"
 	"sync/atomic"
-	"syscall"
 	"time"
 
 	"go.uber.org/zap"
@@ -73,26 +72,28 @@ func (c *Commander) Start(ctx context.Context) error {
 	c.logger.Debug("Starting agent", zap.String("agent", c.cfg.Executable))
 
 	logFilePath := filepath.Join(c.logsDir, "agent.log")
-	logFile, err := os.Create(logFilePath)
+	stdoutFile, err := os.Create(logFilePath)
 	if err != nil {
 		return fmt.Errorf("cannot create %s: %w", logFilePath, err)
 	}
 
 	c.cmd = exec.CommandContext(ctx, c.cfg.Executable, c.args...) // #nosec G204
+	c.cmd.SysProcAttr = sysProcAttrs()
 
 	// Capture standard output and standard error.
 	// https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/21072
-	c.cmd.Stdout = logFile
-	c.cmd.Stderr = logFile
+	c.cmd.Stdout = stdoutFile
+	c.cmd.Stderr = stdoutFile
 
 	if err := c.cmd.Start(); err != nil {
+		stdoutFile.Close()
 		return err
 	}
 
 	c.logger.Debug("Agent process started", zap.Int("pid", c.cmd.Process.Pid))
 	c.running.Store(1)
 
-	go c.watch()
+	go c.watch(stdoutFile)
 
 	return nil
 }
@@ -106,7 +107,9 @@ func (c *Commander) Restart(ctx context.Context) error {
 	return c.Start(ctx)
 }
 
-func (c *Commander) watch() {
+func (c *Commander) watch(stdoutFile *os.File) {
+	defer stdoutFile.Close()
+
 	err := c.cmd.Wait()
 
 	// cmd.Wait returns an exec.ExitError when the Collector exits unsuccessfully or stops
@@ -160,7 +163,7 @@ func (c *Commander) Stop(ctx context.Context) error {
 	c.logger.Debug("Stopping agent process", zap.Int("pid", pid))
 
 	// Gracefully signal process to stop.
-	if err := c.cmd.Process.Signal(syscall.SIGTERM); err != nil {
+	if err := sendShutdownSignal(c.cmd.Process); err != nil {
 		return err
 	}
 
@@ -181,7 +184,7 @@ func (c *Commander) Stop(ctx context.Context) error {
 		c.logger.Debug(
 			"Agent process is not responding to SIGTERM. Sending SIGKILL to kill forcibly.",
 			zap.Int("pid", pid))
-		if innerErr = c.cmd.Process.Signal(syscall.SIGKILL); innerErr != nil {
+		if innerErr = c.cmd.Process.Signal(os.Kill); innerErr != nil {
 			return
 		}
 	}()

cmd/opampsupervisor/supervisor/commander/commander_others.go

@@ -0,0 +1,20 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build !windows
+
+package commander
+
+import (
+	"os"
+	"syscall"
+)
+
+func sendShutdownSignal(process *os.Process) error {
+	return process.Signal(os.Interrupt)
+}
+
+func sysProcAttrs() *syscall.SysProcAttr {
+	// On non-windows systems, no extra attributes are needed.
+	return nil
+}

cmd/opampsupervisor/supervisor/commander/commander_windows.go

@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build windows
+
+package commander
+
+import (
+	"os"
+	"syscall"
+
+	"golang.org/x/sys/windows"
+)
+
+var (
+	kernel32API = windows.NewLazySystemDLL("kernel32.dll")
+
+	ctrlEventProc = kernel32API.NewProc("GenerateConsoleCtrlEvent")
+)
+
+func sendShutdownSignal(process *os.Process) error {
+	// signaling with os.Interrupt is not supported on windows systems,
+	// so we need to use the windows API to properly send a graceful shutdown signal.
+	// See: https://learn.microsoft.com/en-us/windows/console/generateconsolectrlevent
+	r, _, e := ctrlEventProc.Call(syscall.CTRL_BREAK_EVENT, uintptr(process.Pid))
+	if r == 0 {
+		return e
+	}
+
+	return nil
+}
+
+func sysProcAttrs() *syscall.SysProcAttr {
+	// By default, a ctrl-break event applies to a whole process group, which ends up
+	// shutting down the supervisor. Instead, we spawn the collector in its own process
+	// group, so that sending a ctrl-break event shuts down just the collector.
+	return &syscall.SysProcAttr{
+		CreationFlags: syscall.CREATE_NEW_PROCESS_GROUP,
+	}
+}

cmd/opampsupervisor/supervisor/supervisor.go

@@ -459,17 +459,11 @@ func (s *Supervisor) startOpAMPClient() error {
 func (s *Supervisor) startOpAMPServer() error {
 	s.opampServer = server.New(newLoggerFromZap(s.logger))
 
-	var err error
-	s.opampServerPort, err = s.findRandomPort()
-	if err != nil {
-		return err
-	}
-
 	s.logger.Debug("Starting OpAMP server...")
 
 	connected := &atomic.Bool{}
 
-	err = s.opampServer.Start(flattenedSettings{
+	err := s.opampServer.Start(flattenedSettings{
 		endpoint: fmt.Sprintf("localhost:%d", s.opampServerPort),
 		onConnectingFunc: func(_ *http.Request) (bool, int) {
 			// Only allow one agent to be connected the this server at a time.

cmd/opampsupervisor/testdata/collector/split_config.yaml

@@ -11,4 +11,4 @@ service:
       exporters: [nop]
   telemetry:
     resource:
-      test_key: "${file:{{.TestKeyFile}}}"
+      test_key: '${file:{{.TestKeyFile}}}'

cmd/opampsupervisor/testdata/supervisor/supervisor_accepts_conn.yaml

@@ -12,7 +12,7 @@ capabilities:
   accepts_opamp_connection_settings: true
 
 storage:
-  directory: "{{.storage_dir}}"
+  directory: '{{.storage_dir}}'
 
 agent:
   executable: ../../bin/otelcontribcol_{{.goos}}_{{.goarch}}{{.extension}}

cmd/opampsupervisor/testdata/supervisor/supervisor_agent_description.yaml

@@ -12,7 +12,7 @@ capabilities:
   accepts_restart_command: true
 
 storage:
-  directory: "{{.storage_dir}}"
+  directory: '{{.storage_dir}}'
 
 agent:
   executable: ../../bin/otelcontribcol_{{.goos}}_{{.goarch}}{{.extension}}

cmd/opampsupervisor/testdata/supervisor/supervisor_basic.yaml

@@ -12,7 +12,7 @@ capabilities:
   accepts_restart_command: true
 
 storage:
-  directory: "{{.storage_dir}}"
+  directory: '{{.storage_dir}}'
 
 agent:
   executable: ../../bin/otelcontribcol_{{.goos}}_{{.goarch}}{{.extension}}

cmd/opampsupervisor/testdata/supervisor/supervisor_nocap.yaml

@@ -11,7 +11,7 @@ capabilities:
   reports_remote_config: false
 
 storage:
-  directory: "{{.storage_dir}}"
+  directory: '{{.storage_dir}}'
 
 agent:
   executable: ../../bin/otelcontribcol_{{.goos}}_{{.goarch}}{{.extension}}

cmd/opampsupervisor/testdata/supervisor/supervisor_persistence.yaml

@@ -11,7 +11,7 @@ capabilities:
   reports_remote_config: true
 
 storage:
-  directory: {{.storage_dir}}
+  directory: '{{.storage_dir}}'
 
 agent:
   executable: ../../bin/otelcontribcol_{{.goos}}_{{.goarch}}{{.extension}}

cmd/opampsupervisor/testdata/supervisor/supervisor_test.yaml

@@ -11,7 +11,7 @@ capabilities:
   reports_remote_config: true
 
 storage:
-  directory: "{{.storage_dir}}"
+  directory: '{{.storage_dir}}'
 
 agent:
   executable: ../../bin/otelcontribcol_darwin_arm64