feat: add Dockerfile.custom for Debian-based runner image

- 在缓存服务器启动时自动将外部URL转换为host.docker.internal格式
- 添加useHostDockerInternal字段用于标识是否使用host.docker.internal映射
- 自动向容器选项添加--add-host=host.docker.internal:host-gateway参数
- 实现配置文件自动检测功能，当未指定配置文件时默认查找config.yaml
- 在cmd.go中添加PersistentPreRunE钩子函数进行配置文件预处理
- 添加调试输出语句用于跟踪缓存服务器启动流程

Dockerfile.custom

@@ -0,0 +1,17 @@
+FROM debian:bookworm-slim
+
+# 安装必要的工具
+RUN apt-get update && apt-get install -y --no-install-recommends     ca-certificates     curl     git     && rm -rf /var/lib/apt/lists/*
+
+# 复制自定义编译的 act_runner
+# 注意：构建前需要先确保当前目录下有编译好的 act_runner 二进制文件
+COPY act_runner /usr/local/bin/act_runner
+RUN chmod +x /usr/local/bin/act_runner
+
+# 创建数据目录
+RUN mkdir -p /data/cache
+
+WORKDIR /data
+
+ENTRYPOINT ["/usr/local/bin/act_runner"]
+CMD ["daemon", "--config", "/config.yaml"]

internal/app/cmd/cache-server.go

@@ -24,11 +24,12 @@ type cacheServerArgs struct {
 
 func runCacheServer(ctx context.Context, configFile *string, cacheArgs *cacheServerArgs) func(cmd *cobra.Command, args []string) error {
 	return func(cmd *cobra.Command, args []string) error {
+		fmt.Println("cache1")
 		cfg, err := config.LoadDefault(*configFile)
 		if err != nil {
 			return fmt.Errorf("invalid configuration: %w", err)
 		}
-
+		fmt.Println("cache2")
 		initLogging(cfg)
 
 		var (
@@ -47,7 +48,7 @@ func runCacheServer(ctx context.Context, configFile *string, cacheArgs *cacheSer
 		if cacheArgs.Port != 0 {
 			port = cacheArgs.Port
 		}
-
+		fmt.Println("cache2")
 		cacheHandler, err := artifactcache.StartHandler(
 			dir,
 			host,

internal/app/cmd/cmd.go

@@ -15,6 +15,8 @@ import (
 )
 
 func Execute(ctx context.Context) {
+	configFile := ""
+
 	// ./act_runner
 	rootCmd := &cobra.Command{
 		Use:          "act_runner [event name to run]\nIf no event name passed, will default to \"on: push\"",
@@ -22,8 +24,16 @@ func Execute(ctx context.Context) {
 		Args:         cobra.MaximumNArgs(1),
 		Version:      ver.Version(),
 		SilenceUsage: true,
+		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+			// Auto-detect config.yaml if not specified
+			if configFile == "" {
+				if _, err := os.Stat("config.yaml"); err == nil {
+					configFile = "config.yaml"
+				}
+			}
+			return nil
+		},
 	}
-	configFile := ""
 	rootCmd.PersistentFlags().StringVarP(&configFile, "config", "c", "", "Config file path")
 
 	// ./act_runner register

internal/app/run/runner.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"net/url"
 	"path/filepath"
 	"strings"
 	"sync"
@@ -38,6 +39,8 @@ type Runner struct {
 	labels labels.Labels
 	envs   map[string]string
 
+	useHostDockerInternal bool
+
 	runningTasks sync.Map
 }
 
@@ -52,9 +55,14 @@ func NewRunner(cfg *config.Config, reg *config.Registration, cli client.Client)
 	for k, v := range cfg.Runner.Envs {
 		envs[k] = v
 	}
+	// Setup cache
+	useHostDockerInternal := false
 	if cfg.Cache.Enabled == nil || *cfg.Cache.Enabled {
 		if cfg.Cache.ExternalServer != "" {
 			envs["ACTIONS_CACHE_URL"] = cfg.Cache.ExternalServer
+			if strings.Contains(cfg.Cache.ExternalServer, "host.docker.internal") {
+				useHostDockerInternal = true
+			}
 		} else {
 			cacheHandler, err := artifactcache.StartHandler(
 				cfg.Cache.Dir,
@@ -66,7 +74,16 @@ func NewRunner(cfg *config.Config, reg *config.Registration, cli client.Client)
 				log.Errorf("cannot init cache server, it will be disabled: %v", err)
 				// go on
 			} else {
-				envs["ACTIONS_CACHE_URL"] = cacheHandler.ExternalURL() + "/"
+				// Use host.docker.internal for container access
+				externalURL := cacheHandler.ExternalURL()
+				if parsedURL, err := url.Parse(externalURL); err == nil {
+					parsedURL.Host = "host.docker.internal:" + parsedURL.Port()
+					envs["ACTIONS_CACHE_URL"] = parsedURL.String() + "/"
+				} else {
+					envs["ACTIONS_CACHE_URL"] = externalURL + "/"
+				}
+				useHostDockerInternal = true
+				log.Infof("Cache server started at %s, using host.docker.internal for container access", externalURL)
 			}
 		}
 	}
@@ -81,11 +98,12 @@ func NewRunner(cfg *config.Config, reg *config.Registration, cli client.Client)
 	envs["GITEA_ACTIONS_RUNNER_VERSION"] = ver.Version()
 
 	return &Runner{
-		name:   reg.Name,
+		name:                  reg.Name,
-		cfg:    cfg,
+		cfg:                   cfg,
-		client: cli,
+		client:                cli,
-		labels: ls,
+		labels:                ls,
-		envs:   envs,
+		envs:                  envs,
+		useHostDockerInternal: useHostDockerInternal,
 	}
 }
 
@@ -197,6 +215,17 @@ func (r *Runner) run(ctx context.Context, task *runnerv1.Task, reporter *report.
 		maxLifetime = time.Until(deadline)
 	}
 
+	// Auto-add host.docker.internal if cache is enabled
+	containerOptions := r.cfg.Container.Options
+	if r.useHostDockerInternal {
+		if containerOptions == "" {
+			containerOptions = "--add-host=host.docker.internal:host-gateway"
+		} else if !strings.Contains(containerOptions, "--add-host=host.docker.internal") {
+			containerOptions += " --add-host=host.docker.internal:host-gateway"
+		}
+		log.Infof("Auto-added host.docker.internal mapping for cache: %s", containerOptions)
+	}
+
 	runnerConfig := &runner.Config{
 		// On Linux, Workdir will be like "/<parent_directory>/<owner>/<repo>"
 		// On Windows, Workdir will be like "\<parent_directory>\<owner>\<repo>"
@@ -219,7 +248,7 @@ func (r *Runner) run(ctx context.Context, task *runnerv1.Task, reporter *report.
 		ContainerNamePrefix:   fmt.Sprintf("GITEA-ACTIONS-TASK-%d", task.Id),
 		ContainerMaxLifetime:  maxLifetime,
 		ContainerNetworkMode:  container.NetworkMode(r.cfg.Container.Network),
-		ContainerOptions:      r.cfg.Container.Options,
+		ContainerOptions:      containerOptions,
 		ContainerDaemonSocket: r.cfg.Container.DockerHost,
 		Privileged:            r.cfg.Container.Privileged,
 		DefaultActionInstance: r.getDefaultActionsURL(ctx, task),