Merge pull request #6 from concourse/version-from-file

Emit version from file

Author: taylorsilva

README.md

@@ -73,3 +73,5 @@ Since the mock resource is included as a base resource type, it can be used as t
 * `version`: Version to create.
 
 * `print_env`: Print all environment variables to stdout when set to true. Default false.
+
+* `file`: Contents will be read from the file and emitted as the version

cmd/out/main.go

@@ -49,7 +49,7 @@ func main() {
 		logrus.Info(req.Source.Log)
 	}
 
-	if req.Params.Version == "" {
+	if req.Params.Version == "" && req.Params.File == "" {
 		logrus.Fatal("no version specified")
 		return
 	}
@@ -60,8 +60,20 @@ func main() {
 		return
 	}
 
-	version := resource.Version{
-		Version: req.Params.Version,
+	var version resource.Version
+	if req.Params.Version == "" {
+		contents, err := os.ReadFile(req.Params.File)
+		if err != nil {
+			logrus.Fatalf("error reading version from file %s: %s", req.Params.File, err)
+			return
+		}
+		version = resource.Version{
+			Version: string(contents),
+		}
+	} else {
+		version = resource.Version{
+			Version: req.Params.Version,
+		}
 	}
 
 	if privileged {

types.go

@@ -74,6 +74,9 @@ type PutParams struct {
 
 	// print all env vars to stdout
 	PrintEnv bool `json:"print_env"`
+
+	// file whose contents will be the version
+	File string `json:"file"`
 }
 
 type MetadataField struct {