fix: stop a stalled docker daemon from hanging jobs and the e2e suite (#1404)

When the docker daemon stopped answering on https://gitea.com/gitea/runner/actions/runs/1204971, unbounded exec runs hung the e2e suite until the 20m `go test` panic, which skipped teardown. Exec runs and teardown are now bounded, and attached exec streams, including the runner's user ID probe, close with their context.

CLI daemons now stop with SIGTERM, so job volumes no longer leak.

_Written by Claude (Opus 5.5)._

---------

Co-authored-by: bircni <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1404
Reviewed-by: bircni <[email protected]>
Co-authored-by: silverwind <[email protected]>

e2e/modes_test.go

@@ -9,6 +9,7 @@ import (
 	"bufio"
 	"bytes"
 	"cmp"
+	"context"
 	"encoding/json"
 	"errors"
 	"os"
@@ -138,14 +139,31 @@ func daemonWorkflow(t *testing.T, m mode, spec workflowSpec) *workflowResult {
 	return result
 }
 
-func execWorkflow(t *testing.T, m mode, spec workflowSpec) *workflowResult {
+func runExec(t *testing.T, env []string, args ...string) (stdout, stderr []byte, err error) {
 	t.Helper()
-	ctx := t.Context()
-
 	bin, err := runnerBinary()
 	if err != nil {
 		t.Fatal(err)
 	}
+	ctx, cancel := context.WithTimeout(t.Context(), runTimeout)
+	defer cancel()
+	cmd := exec.CommandContext(ctx, bin, append([]string{"exec"}, args...)...)
+	cmd.Env = append(slices.DeleteFunc(os.Environ(), func(kv string) bool { return strings.HasPrefix(kv, "ACTIONS_") }), env...)
+	cmd.Cancel = func() error { return cmd.Process.Signal(os.Interrupt) }
+	cmd.WaitDelay = cleanupTimeout
+	var stdoutBuf, stderrBuf bytes.Buffer
+	cmd.Stdout, cmd.Stderr = &stdoutBuf, &stderrBuf
+	err = cmd.Run()
+	if ctx.Err() != nil {
+		t.Fatalf("exec did not finish within %s\n%s%s", runTimeout, stdoutBuf.Bytes(), stderrBuf.Bytes())
+	}
+	return stdoutBuf.Bytes(), stderrBuf.Bytes(), err
+}
+
+func execWorkflow(t *testing.T, m mode, spec workflowSpec) *workflowResult {
+	t.Helper()
+	ctx := t.Context()
+
 	workdir := t.TempDir()
 	workflows := filepath.Join(workdir, ".gitea", "workflows")
 	if err := os.MkdirAll(workflows, 0o755); err != nil {
@@ -170,12 +188,12 @@ func execWorkflow(t *testing.T, m mode, spec workflowSpec) *workflowResult {
 		}
 	}
 
-	args := []string{"exec", "--json", "-C", workdir, "-W", workflows, "--artifact-server-path", t.TempDir(), "--artifact-server-port", "0"}
-	env := slices.DeleteFunc(os.Environ(), func(kv string) bool { return strings.HasPrefix(kv, "ACTIONS_") })
+	args := []string{"--json", "-C", workdir, "-W", workflows, "--artifact-server-path", t.TempDir(), "--artifact-server-port", "0"}
+	var env []string
 	if m.kubernetes {
 		cluster := requireCluster(t)
 		args = append(args, "-i", "kubernetes://"+cluster.jobImage)
-		env = append(env, "KUBECONFIG="+cluster.kubernetes.Kubeconfig)
+		env = []string{"KUBECONFIG=" + cluster.kubernetes.Kubeconfig}
 	} else {
 		args = append(args, "-i", os.Getenv("E2E_JOB_IMAGE"), "--network", fixture.network)
 	}
@@ -185,21 +203,17 @@ func execWorkflow(t *testing.T, m mode, spec workflowSpec) *workflowResult {
 			args = append(args, "--input", name+"="+value)
 		}
 	}
-	cmd := exec.CommandContext(ctx, bin, append(args, spec.execArgs...)...)
-	cmd.Env = env
-	var stdout, stderr bytes.Buffer
-	cmd.Stdout, cmd.Stderr = &stdout, &stderr
-	runErr := cmd.Run()
+	stdout, stderr, runErr := runExec(t, env, append(args, spec.execArgs...)...)
 	var exitErr *exec.ExitError
 	if runErr != nil && !errors.As(runErr, &exitErr) {
-		t.Fatalf("exec: %v\n%s", runErr, stderr.String())
+		t.Fatalf("exec: %v\n%s", runErr, stderr)
 	}
 
 	result := &workflowResult{conclusion: "success", jobs: map[string]string{}}
 	if runErr != nil {
 		result.conclusion = "failure"
 	}
-	scanner := bufio.NewScanner(&stdout)
+	scanner := bufio.NewScanner(bytes.NewReader(stdout))
 	scanner.Buffer(nil, 1<<20)
 	for scanner.Scan() {
 		var entry struct {
@@ -220,8 +234,8 @@ func execWorkflow(t *testing.T, m mode, spec workflowSpec) *workflowResult {
 			}
 		}
 	}
-	if result.conclusion != "success" && len(result.jobs) == 0 {
-		t.Fatalf("exec ran no job: %v\n%s", runErr, stderr.String())
+	if len(result.jobs) == 0 {
+		t.Fatalf("exec ran no job: %v\n%s", runErr, stderr)
 	}
 	return result
 }