Apply explicit CLI configuration overrides

example_test.go

@@ -115,3 +115,22 @@ func ExampleSecretEnv() {
 	fmt.Println(result.Config.APIKey.EnvName(), result.Config.APIKey.IsResolved(), err)
 	// Output: CONFIGKIT_EXAMPLE_API_KEY true <nil>
 }
+
+func ExampleOverride() {
+	type Config struct {
+		Workers int `yaml:"workers"`
+	}
+	workers, workersWasSet := 0, true // Supplied by the application's CLI parser.
+	var overrides []configkit.Override
+	if workersWasSet {
+		overrides = append(overrides, configkit.Override{
+			Path: configkit.Keys("workers"), Value: workers, Flag: "--workers",
+		})
+	}
+	result, err := configkit.Load(configkit.NoSource(), configkit.Options[Config]{
+		Definition: configkit.Definition[Config]{Defaults: func() Config { return Config{Workers: 4} }},
+		Overrides:  overrides,
+	})
+	fmt.Println(result.Config.Workers, result.Sources()[0].Label, err)
+	// Output: 0 --workers <nil>
+}