WIP: abra recipe upgrade on the way

catalogue/catalogue.go

@@ -219,3 +219,27 @@ func readAppsCatalogueWeb(target interface{}) error {
 
 	return nil
 }
+
+func VersionsOfService(recipe, serviceName string) ([]string, error) {
+	catl, err := ReadAppsCatalogue()
+	if err != nil {
+		return nil, err
+	}
+
+	app, ok := catl[recipe]
+	if !ok {
+		return nil, fmt.Errorf("recipe '%s' does not exist?", recipe)
+	}
+
+	versions := []string{}
+	alreadySeen := make(map[string]bool)
+	for version := range app.Versions {
+		appVersion := app.Versions[version][serviceName].Tag
+		if _, ok := alreadySeen[appVersion]; !ok {
+			alreadySeen[appVersion] = true
+			versions = append(versions, appVersion)
+		}
+	}
+
+	return versions, nil
+}