altsrc: Parse durations from strings

altsrc/map_input_source.go

@@ -71,24 +71,28 @@ func (fsm *MapInputSource) Int(name string) (int, error) {
 func (fsm *MapInputSource) Duration(name string) (time.Duration, error) {
 	otherGenericValue, exists := fsm.valueMap[name]
 	if exists {
-		otherValue, isType := otherGenericValue.(time.Duration)
+		return castDuration(name, otherGenericValue)
-		if !isType {
-			return 0, incorrectTypeForFlagError(name, "duration", otherGenericValue)
-		}
-		return otherValue, nil
 	}
 	nestedGenericValue, exists := nestedVal(name, fsm.valueMap)
 	if exists {
-		otherValue, isType := nestedGenericValue.(time.Duration)
+		return castDuration(name, nestedGenericValue)
-		if !isType {
-			return 0, incorrectTypeForFlagError(name, "duration", nestedGenericValue)
-		}
-		return otherValue, nil
 	}
 
 	return 0, nil
 }
 
+func castDuration(name string, value interface{}) (time.Duration, error) {
+	if otherValue, isType := value.(time.Duration); isType {
+		return otherValue, nil
+	}
+	otherStringValue, isType := value.(string)
+	parsedValue, err := time.ParseDuration(otherStringValue)
+	if !isType || err != nil {
+		return 0, incorrectTypeForFlagError(name, "duration", value)
+	}
+	return parsedValue, nil
+}
+
 // Float64 returns an float64 from the map if it exists otherwise returns 0
 func (fsm *MapInputSource) Float64(name string) (float64, error) {
 	otherGenericValue, exists := fsm.valueMap[name]

altsrc/map_input_source_test.go

@@ -0,0 +1,25 @@
+package altsrc
+
+import (
+	"testing"
+	"time"
+)
+
+func TestMapDuration(t *testing.T) {
+	inputSource := &MapInputSource{
+		file: "test",
+		valueMap: map[interface{}]interface{}{
+			"duration_of_duration_type": time.Minute,
+			"duration_of_string_type":   "1m",
+			"duration_of_int_type":      1000,
+		},
+	}
+	d, err := inputSource.Duration("duration_of_duration_type")
+	expect(t, time.Minute, d)
+	expect(t, nil, err)
+	d, err = inputSource.Duration("duration_of_string_type")
+	expect(t, time.Minute, d)
+	expect(t, nil, err)
+	d, err = inputSource.Duration("duration_of_int_type")
+	refute(t, nil, err)
+}