Add supported Version.Check values as consts

cmd/ipfs/ipfs.go

@@ -119,13 +119,13 @@ func localNode(confdir string, online bool) (*core.IpfsNode, error) {
 		return nil, err
 	}
 
-	if cfg.Version.Check != "ignore" {
+	if cfg.Version.Check != config.CheckIgnore {
 		obsolete := checkForUpdates()
 		if obsolete != nil {
-			fmt.Println(obsolete)
-			if cfg.Version.Check == "error" {
+			if cfg.Version.Check == config.CheckError {
 				return nil, obsolete
 			}
+			fmt.Println(obsolete) // when "warn" version.check mode we just show warning message
 		}
 	}
 

config/config.go

@@ -51,6 +51,12 @@ type Version struct {
 	Current string `json:"current"` // ipfs version for which config was generated
 }
 
+const (
+	CheckError  = "error"  // value for Version.Check to raise error and exit if version is obsolete
+	CheckWarn   = "warn"   // value for Version.Check to show warning message if version is obsolete
+	CheckIgnore = "ignore" // value for Version.Check to not perform update check
+)
+
 // Config is used to load IPFS config files.
 type Config struct {
 	Identity  Identity         // local node's peer identity