login: default to SRC_ENDPOINT (#414)

Author: bobheadxi

CHANGELOG.md

@@ -15,6 +15,8 @@ All notable changes to `src-cli` are documented in this file.
 
 ### Changed
 
+- `src login` now defaults to validating against `SRC_ENDPOINT` if configured.
+
 ### Fixed
 
 ### Removed

cmd/src/login.go

@@ -38,11 +38,15 @@ Examples:
 		if err := flagSet.Parse(args); err != nil {
 			return err
 		}
-		if len(args) != 1 {
-			return &usageError{errors.New("expected exactly one argument: the Sourcegraph URL")}
+		endpoint := cfg.Endpoint
+		if len(args) == 1 {
+			endpoint = args[0]
 		}
-		endpointArg := args[0]
-		return loginCmd(context.Background(), cfg, endpointArg, os.Stdout)
+		if endpoint == "" {
+			return &usageError{errors.New("expected exactly one argument: the Sourcegraph URL, or SRC_ENDPOINT to be set")}
+		}
+
+		return loginCmd(context.Background(), cfg, endpoint, os.Stdout)
 	}
 
 	commands = append(commands, &command{