cmd/go-cache-plugin: add a setting to use S3 path-style URLs

This allows using the plugin with other S3-compatible storage implementations
that do not support the default virtual-hosted format.
Can also use the AWS_ENDPOINT_URL environment variable to customize
the s3 address.

Signed-off-by: Asutorufa <[email protected]>

Author: Asutorufa

cmd/go-cache-plugin/commands.go

@@ -26,6 +26,7 @@ var flags struct {
 	CacheDir      string        `flag:"cache-dir,default=$GOCACHE_DIR,Local cache directory (required)"`
 	S3Bucket      string        `flag:"bucket,default=$GOCACHE_S3_BUCKET,S3 bucket name (required)"`
 	S3Region      string        `flag:"region,default=$GOCACHE_S3_REGION,S3 region"`
+	S3PathStyle   bool          `flag:"s3-path-style,default=$GOCACHE_S3_PATH_STYLE,S3 path-style URLs (optional)"`
 	KeyPrefix     string        `flag:"prefix,default=$GOCACHE_KEY_PREFIX,S3 key prefix (optional)"`
 	MinUploadSize int64         `flag:"min-upload-size,default=$GOCACHE_MIN_SIZE,Minimum object size to upload to S3 (in bytes)"`
 	Concurrency   int           `flag:"c,default=$GOCACHE_CONCURRENCY,Maximum number of concurrent requests"`

cmd/go-cache-plugin/help.go

@@ -19,8 +19,8 @@ See also "help environment".
 
 The plugin requires credentials to access S3. If you are running in AWS, it can
 get credentials from the instance metadata service; otherwise you will need to
-plumb AWS environment variables (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY) or
-set up a configuration file.
+plumb AWS environment variables (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, 
+AWS_ENDPOINT_URL) or set up a configuration file.
 
 See also: "help environment".
 Related:  "direct-mode", "serve-mode", "module-proxy", "reverse-proxy".`,
@@ -38,6 +38,7 @@ settings can be set via environment variables as well as flags.
     --cache-dir       GOCACHE_DIR            path        (required)
     --bucket          GOCACHE_S3_BUCKET      string      (required)
     --region          GOCACHE_S3_REGION      string      based on bucket
+    --s3-path-style   GOCACHE_S3_PATH_STYLE  bool        false
     --prefix          GOCACHE_KEY_PREFIX     string      ""
     --min-upload-size GOCACHE_MIN_SIZE       int64       0
     --metrics         GOCACHE_METRICS        bool        false

cmd/go-cache-plugin/setup.go

@@ -59,7 +59,9 @@ func initCacheServer(env *command.Env) (*gocache.Server, *s3util.Client, error)
 	vprintf("local cache directory: %s", flags.CacheDir)
 	vprintf("S3 cache bucket %q (%s)", flags.S3Bucket, region)
 	client := &s3util.Client{
-		Client: s3.NewFromConfig(cfg),
+		Client: s3.NewFromConfig(cfg, func(o *s3.Options) {
+			o.UsePathStyle = flags.S3PathStyle
+		}),
 		Bucket: flags.S3Bucket,
 	}
 	cache := &gobuild.S3Cache{