Introduce --guest-builds-dir and --guest-cache-dir (#63)

* Introduce --guest-builds-dir and --guest-cache-dir * README.md: better explain the difference between config stage options * Better clarify --guest-builds-dir and --guest-cache-dir
cirruslabs · Feb 19, 2024 · 921eca7 · 921eca7
1 parent d8d241b
commit 921eca7
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diff --git a/README.md b/README.md
@@ -143,10 +143,14 @@ that required paid sponsorship upon exceeding a free limit.
 
 ### `config` stage
 
-| Argument       | Default | Description                                             |
-|----------------|---------|---------------------------------------------------------|
-| `--builds-dir` |         | Path to a directory on host to use for storing builds   |
-| `--cache-dir`  |         | Path to a directory on host to use for caching purposes |
+| Argument                         | Default | Description                                                                                                                                                                                           |
+|----------------------------------|---------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `--builds-dir`                   |         | Path to a directory on host to use for storing builds, automatically mounts that directory to the guest VM (mutually exclusive with `--guest-builds-dir`)                                             |
+| `--cache-dir`                    |         | Path to a directory on host to use for caching purposes, automatically mounts that directory to the guest VM (mutually exclusive with `--guest-cache-dir`)                                            |
+| `--guest-builds-dir`<sup>1</sup> |         | Path to a directory in guest to use for storing builds, useful when mounting a block device (via [`--disk` command-line argument](#prepare-stage)) to the VM (mutually exclusive with `--builds-dir`) |
+| `--guest-cache-dir`<sup>1</sup>  |         | Path to a directory in guest to use for caching purposes, useful when mounting a block device (via [`--disk` command-line argument](#prepare-stage) to the VM (mutually exclusive with `--cache-dir`) |
+
+<sup>1</sup>: this is an advanced feature which should only be resorted to when the standard directory sharing via `--builds-dir` and `--cache-dir` is not sufficient for some reason.
 
 ### `prepare` stage
 

diff --git a/internal/commands/config/config.go b/internal/commands/config/config.go
@@ -12,22 +12,35 @@ import (
 
 var ErrConfigFailed = errors.New("configuration stage failed")
 
-var buildsDir string
-var cacheDir string
+var (
+	buildsDir string
+	cacheDir  string
+
+	guestBuildsDir string
+	guestCacheDir  string
+)
 
 func NewCommand() *cobra.Command {
-	command := &cobra.Command{
+	cmd := &cobra.Command{
 		Use:   "config",
 		Short: "Configure GitLab Runner",
 		RunE:  runConfig,
 	}
 
-	command.PersistentFlags().StringVar(&buildsDir, "builds-dir", "",
-		"Path to a directory on host to use for storing builds")
-	command.PersistentFlags().StringVar(&cacheDir, "cache-dir", "",
-		"path to a directory on host to use for caching purposes")
-
-	return command
+	cmd.PersistentFlags().StringVar(&buildsDir, "builds-dir", "",
+		"path to a directory on host to use for storing builds, automatically mounts that directory "+
+			"to the guest VM, mutually exclusive with \"--guest-builds-dir\"")
+	cmd.PersistentFlags().StringVar(&cacheDir, "cache-dir", "",
+		"path to a directory on host to use for caching purposes, automatically mounts that directory "+
+			"to the guest VM, mutually exclusive with \"--guest-cache-dir\"")
+	cmd.PersistentFlags().StringVar(&guestBuildsDir, "guest-builds-dir", "",
+		"path to a directory in guest to use for storing builds, useful when mounting a block device "+
+			"via \"--disk\" command-line argument (mutually exclusive with \"--builds-dir\")")
+	cmd.PersistentFlags().StringVar(&guestCacheDir, "guest-cache-dir", "",
+		"path to a directory in guest to use for caching purposes, useful when mounting a block device "+
+			"via \"--disk\" command-line argument (mutually exclusive with \"--cache-dir\")")
+
+	return cmd
 }
 
 func runConfig(cmd *cobra.Command, args []string) error {
@@ -59,34 +72,58 @@ func runConfig(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	// Validate environment variables and command-line arguments combinations
 	if tartConfig.HostDir && buildsDir != "" {
 		return fmt.Errorf("%w: --builds-dir and TART_EXECUTOR_HOST_DIR are mutually exclusive",
 			ErrConfigFailed)
 	}
-	if tartConfig.HostDir {
+	if tartConfig.HostDir && guestBuildsDir != "" {
+		return fmt.Errorf("%w: --guest-builds-dir and TART_EXECUTOR_HOST_DIR are mutually exclusive",
+			ErrConfigFailed)
+	}
+
+	if buildsDir != "" && guestBuildsDir != "" {
+		return fmt.Errorf("%w: --builds-dir and --guest-builds-dir are mutually exclusive",
+			ErrConfigFailed)
+	}
+
+	if cacheDir != "" && guestCacheDir != "" {
+		return fmt.Errorf("%w: --cache-dir and --guest-cache-dir are mutually exclusive",
+			ErrConfigFailed)
+	}
+
+	// Figure out the builds directory override to use
+	switch {
+	case tartConfig.HostDir:
 		gitlabRunnerConfig.BuildsDir = "/Volumes/My Shared Files/hostdir"
 
 		if err := os.MkdirAll(gitLabEnv.HostDirPath(), 0700); err != nil {
 			return err
 		}
-	} else if buildsDir != "" {
+	case buildsDir != "":
 		gitlabRunnerConfig.BuildsDir = "/Volumes/My Shared Files/buildsdir"
 		buildsDir = os.ExpandEnv(buildsDir)
 		gitlabRunnerConfig.JobEnv[tart.EnvTartExecutorInternalBuildsDir] = buildsDir
 
 		if err := os.MkdirAll(buildsDir, 0700); err != nil {
 			return err
 		}
+	case guestBuildsDir != "":
+		gitlabRunnerConfig.BuildsDir = guestBuildsDir
 	}
 
-	if cacheDir != "" {
+	// Figure out the cache directory override to use
+	switch {
+	case cacheDir != "":
 		gitlabRunnerConfig.CacheDir = "/Volumes/My Shared Files/cachedir"
 		cacheDir = os.ExpandEnv(cacheDir)
 		gitlabRunnerConfig.JobEnv[tart.EnvTartExecutorInternalCacheDir] = cacheDir
 
 		if err := os.MkdirAll(cacheDir, 0700); err != nil {
 			return err
 		}
+	case guestCacheDir != "":
+		gitlabRunnerConfig.CacheDir = guestCacheDir
 	}
 
 	jsonBytes, err := json.MarshalIndent(&gitlabRunnerConfig, "", "  ")