Merge pull request #35 from TheDevMinerTV/feat/npm-cache-reuse

feat: NPM cache reuse

README.md

@@ -16,6 +16,9 @@ The following additional flags are available:
 ```
 --short      : Print a shorter version of the package report, ideal for posts to Twitter
 --no-cleanup : Don't remove the temporary directory after the calculation
+
+--npm-cache <DIRECTORY>: Use the specified directory as the NPM cache, defaults to generating a temporary directory
+--npm-cache-read-write : Mount the NPM cache directory as read-write, defaults to true, only honored if --npm-cache is specified
 ```
 
 ## License

docker.go

@@ -104,19 +104,17 @@ func runContainer(ctx context.Context, cmd []string, tmpDir internal.TmpDir) err
 		},
 	}
 
-	if MountNPMCache != "" {
-		if !filepath.IsAbs(MountNPMCache) {
-			return fmt.Errorf("MountNPMCache must be an absolute path")
-		}
-
-		hostConfig.Mounts = append(hostConfig.Mounts, docker_mount.Mount{
-			Type:     docker_mount.TypeBind,
-			Source:   MountNPMCache,
-			Target:   "/root/.npm",
-			ReadOnly: true,
-		})
+	hostConfig.Mounts = append(hostConfig.Mounts, docker_mount.Mount{
+		Type:     docker_mount.TypeBind,
+		Source:   string(npmCache),
+		Target:   "/root/.cache/npm",
+		ReadOnly: npmCacheRO,
+	})
 
-		log.Info().Str("path", MountNPMCache).Msg("Mounting readonly NPM cache")
+	if npmCacheRO {
+		log.Info().Str("path", string(npmCache)).Msg("Mounting readonly NPM cache")
+	} else {
+		log.Info().Str("path", string(npmCache)).Msg("Mounting NPM cache")
 	}
 
 	c, err := dockerC.ContainerCreate(ctx, &config, &hostConfig, nil, nil, "")

main.go

@@ -14,16 +14,20 @@ import (
 )
 
 const (
-	BaseImage     = "node:22"
-	MountNPMCache = ""
+	BaseImage = "node:22"
 )
 
 var (
 	npmClient *npm.Client
 	dockerC   *docker_client.Client
 
-	fShortMode = flag.Bool("short", false, "Print a shorter version of the package report, ideal for posts to Twitter")
-	fNoCleanup = flag.Bool("no-cleanup", false, "Do not cleanup the temporary directories after the execution")
+	npmCache   internal.TmpDir
+	npmCacheRO = false
+
+	fShortMode  = flag.Bool("short", false, "Print a shorter version of the package report, ideal for posts to Twitter")
+	fNoCleanup  = flag.Bool("no-cleanup", false, "Do not cleanup the temporary directories after the execution")
+	fNPMCache   = flag.String("npm-cache", "", "Use the specified directory as the NPM cache")
+	fNPMCacheRW = flag.Bool("npm-cache-rw", true, "Mount the NPM cache directory as read-write")
 )
 
 func main() {
@@ -48,6 +52,29 @@ func main() {
 		log.Fatal().Err(err).Msg("Failed to download Node 22 image")
 	}
 
+	if *fNPMCache == "" {
+		npmCache, err = internal.NewTmpDir("npm_cache_*")
+		if err != nil {
+			log.Fatal().Err(err).Msg("Failed to create temporary directory for NPM cache")
+		}
+		defer func() {
+			if !*fNoCleanup {
+				return
+			}
+
+			npmCache.Remove()
+
+			log.Debug().Str("dir", npmCache.String()).Msg("Cleaned up temporary directory for NPM cache")
+		}()
+
+		log.Debug().Str("dir", npmCache.String()).Msg("Created temporary directory for NPM cache")
+	} else {
+		npmCache = internal.TmpDir(*fNPMCache)
+		npmCacheRO = !*fNPMCacheRW
+
+		log.Debug().Str("dir", npmCache.String()).Bool("readonly", npmCacheRO).Msg("Using specified directory as NPM cache")
+	}
+
 	variant, _, err := internal.RunSelect(&promptui.Select{
 		Label: "Select variant",
 		Items: []string{"Calculate size differences for replacing/removing dependencies", "Calculate size difference between package versions"},