Add cache maintenance locking

README.md

@@ -1,5 +1,9 @@
 # GitLab Project Manager
 
+## TODO
+
+- Fix NPE when cache is reset or project for whatever reason leaves an orphaned alias
+
 ## Purpose
 
 The goal of this utility is to provide a fuzzy-find method of locating, cloning,

cmd/alias_list.go

@@ -23,8 +23,7 @@ func runListAliasCmd(cmd *cobra.Command, args []string) {
 		WithBoxStyle(&pterm.Style{pterm.FgLightBlue}).
 		WithTitle(pterm.Bold.Sprint(pterm.LightGreen("Aliases by Project"))).
 		Print("\n" + cache.AliasesByProjectString())
-	fmt.Println("\n")
-	// fmt.Print("\n" + cache.AliasesByProjectString() + "\n")
+	fmt.Print("\n\n")
 }
 
 func init() {

cmd/cache.go

@@ -14,16 +14,18 @@ var cacheCmd = &cobra.Command{
 	Use:               "cache",
 	Short:             "Manage GitLab project cache",
 	Long:              cacheCmdLong,
-	PersistentPreRun:  initCacheCmd,
+	PersistentPreRun:  runCacheCmd,
 	PersistentPostRun: postCacheCmd,
 }
 
-func initCacheCmd(cmd *cobra.Command, args []string) {
+func runCacheCmd(cmd *cobra.Command, args []string) {
 	initProjectCache(cmd, args)
+	cache.LockCache()
 }
 
 func postCacheCmd(cmd *cobra.Command, args []string) {
 	postProjectCache(cmd, args)
+	cache.UnlockCache()
 }
 
 func init() {

internal/projects/cache.go

@@ -51,6 +51,33 @@ func (c *Cache) Load() error {
 	return err
 }
 
+func (c *Cache) UnlockCache() {
+	c.log.Info("Unlocking cache")
+	if err := os.Remove(c.file + ".lock"); err != nil {
+		c.log.Fatal("Failed unlocking cache, manual rm may be necessary",
+			c.log.Args("error", err, "lockFile", c.file+".lock"),
+		)
+	}
+}
+
+func (c *Cache) LockCache() {
+	c.log.Info("Attempting to lock cache")
+	c.checkLock()
+
+	file, err := os.OpenFile(c.file+".lock", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0640)
+	defer file.Close()
+
+	if err != nil {
+		c.log.Fatal("Failed to lock cache", c.log.Args("error", err))
+	}
+}
+
+func (c *Cache) checkLock() {
+	if _, err := os.Stat(c.file + ".lock"); err == nil {
+		c.log.Fatal("Can't manage cache, already locked")
+	}
+}
+
 // Saves the current state of the cache to disk
 func (c *Cache) write() {
 	file, err := os.OpenFile(c.file, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0640)