perf: cut redundant work out of job setup and teardown (#1218)

Implement speedups to job start and shutdown.

- Create the job container while services are still becoming healthy, and poll their health at a flat one second instead of a 2s to 32s doubling backoff
- Pull each service image once instead of twice, and fetch a warm action cache once instead of twice
- Report the job result before reclaiming its volumes, and reap volumes stranded by a runner that died mid-job

| Step | Scenario | Before | After |
| --- | --- | --- | --- |
| Complete job | Large workspace volume | 4.2s | 0.4s |
| Set up job | One service, 2s health interval | 7.08s | 3.26s |
| Set up job | Two cached actions from github.com | 1.81s | 1.34s |
| Set up job | Two cached actions from gitea.com | 2.42s | 1.95s |
| Set up job | Two actions, cold action cache | 6.62s | unchanged |
| Set up job | Minimal job, no services or actions | 0.62s | unchanged |

Assisted-by: Claude Code:Opus 5
Reviewed-on: https://gitea.com/gitea/runner/pulls/1218
Reviewed-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>

act/container/docker_volume.go

@@ -8,40 +8,67 @@ package container
 
 import (
 	"context"
+	"errors"
+	"fmt"
+	"time"
 
 	"gitea.com/gitea/runner/act/common"
 
+	cerrdefs "github.com/containerd/errdefs"
 	"github.com/moby/moby/client"
 )
 
-func NewDockerVolumeRemoveExecutor(volumeName string, force bool) common.Executor {
-	return func(ctx context.Context) error {
-		cli, err := GetDockerClient(ctx)
-		if err != nil {
-			return err
-		}
-		defer cli.Close()
-
-		list, err := cli.VolumeList(ctx, client.VolumeListOptions{})
-		if err != nil {
-			return err
-		}
-
-		for _, vol := range list.Items {
-			if vol.Name == volumeName {
-				return removeExecutor(volumeName, force)(ctx)
-			}
-		}
-
-		// Volume not found - do nothing
-		return nil
+func CreateJobVolumes(ctx context.Context, runnerUUID string, volumeNames []string) error {
+	cli, err := GetDockerClient(ctx)
+	if err != nil {
+		return err
 	}
+	defer cli.Close()
+
+	for _, volumeName := range volumeNames {
+		if _, err := cli.VolumeCreate(ctx, client.VolumeCreateOptions{
+			Name:   volumeName,
+			Labels: runnerLabels(runnerUUID),
+		}); err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
-func removeExecutor(volume string, force bool) common.Executor {
+func RemoveOrphanJobVolumes(ctx context.Context, runnerUUID string, createdBefore time.Time) error {
+	cli, err := GetDockerClient(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to connect to the docker daemon: %w", err)
+	}
+	defer cli.Close()
+
+	volumes, err := cli.VolumeList(ctx, client.VolumeListOptions{
+		Filters: make(client.Filters).Add("label", runnerUUIDLabel+"="+runnerUUID).Add("dangling", "true"),
+	})
+	if err != nil {
+		return err
+	}
+
+	var errs []error
+	for _, item := range volumes.Items {
+		created, err := time.Parse(time.RFC3339, item.CreatedAt)
+		// an unreadable or recent timestamp may belong to a job that is still starting up
+		if err != nil || created.After(createdBefore) || item.Labels[runnerUUIDLabel] != runnerUUID {
+			continue
+		}
+		if _, err := cli.VolumeRemove(ctx, item.Name, client.VolumeRemoveOptions{}); err != nil && !cerrdefs.IsNotFound(err) {
+			errs = append(errs, fmt.Errorf("failed to remove volume %s: %w", item.Name, err))
+			continue
+		}
+		common.Logger(ctx).Infof("removed docker volume %s left behind by an earlier job", item.Name)
+	}
+	return errors.Join(errs...)
+}
+
+func NewDockerVolumeRemoveExecutor(volumeName string, force bool) common.Executor {
 	return func(ctx context.Context) error {
-		logger := common.Logger(ctx)
-		logger.Debugf("docker volume rm %s", volume)
+		common.Logger(ctx).Debugf("docker volume rm %s", volumeName)
 
 		if common.Dryrun(ctx) {
 			return nil
@@ -53,7 +80,10 @@ func removeExecutor(volume string, force bool) common.Executor {
 		}
 		defer cli.Close()
 
-		_, err = cli.VolumeRemove(ctx, volume, client.VolumeRemoveOptions{Force: force})
+		_, err = cli.VolumeRemove(ctx, volumeName, client.VolumeRemoveOptions{Force: force})
+		if cerrdefs.IsNotFound(err) { // already gone is the outcome we wanted
+			return nil
+		}
 		return err
 	}
 }