feat: Support string duration format in config files (#408)

* Create new type to use when you need duration in config

* Support new duration format without custom type

* Compare types, not names

Author: rewenset

Gopkg.lock

@@ -17,8 +17,11 @@ package config
 import (
 	"io/ioutil"
 	"os"
+	"reflect"
+	"time"
 
 	"github.com/ghodss/yaml"
+	"github.com/mitchellh/mapstructure"
 )
 
 // ParseConfigFromYamlFile parses a configuration from a file in YAML
@@ -33,8 +36,37 @@ func ParseConfigFromYamlFile(path string, cfg interface{}) error {
 	if err != nil {
 		return err
 	}
+	return parseConfigFromYamlBytes(b, cfg)
+}
+
+func parseConfigFromYamlBytes(b []byte, cfg interface{}) error {
+	var data map[string]interface{}
+	err := yaml.Unmarshal(b, &data)
+	if err != nil {
+		return err
+	}
 
-	err = yaml.Unmarshal(b, cfg)
+	dc := &mapstructure.DecoderConfig{
+		DecodeHook: func(in, out reflect.Type, data interface{}) (interface{}, error) {
+			// Only intended to help with cases when string must be set to `time.Duration`
+			if in.Kind() != reflect.String || out != reflect.TypeOf(time.Duration(0)) {
+				return data, nil
+			}
+
+			pd, err := time.ParseDuration(data.(string))
+			if err != nil {
+				return nil, err
+			}
+			return pd, nil
+		},
+		Result:  cfg,
+		TagName: "json",
+	}
+	dec, err := mapstructure.NewDecoder(dc)
+	if err != nil {
+		return err
+	}
+	err = dec.Decode(data)
 	if err != nil {
 		return err
 	}

config/parser.go

@@ -0,0 +1,54 @@
+package config
+
+import (
+	"testing"
+	"time"
+
+	. "github.com/onsi/gomega"
+)
+
+func TestParseConfigFromYamlBytes(t *testing.T) {
+	RegisterTestingT(t)
+
+	type Duration string
+
+	type BigConfig struct {
+		Simple     string
+		Str        string `json:"name"`
+		Integer16  int16
+		Timeout    time.Duration
+		NotTimeout Duration
+	}
+
+	var testData = map[string]struct {
+		input string
+		want  BigConfig
+		fail  bool
+	}{
+		"simple":          {"simple: test", BigConfig{Simple: "test"}, false},
+		"bad simple":      {"simple test", BigConfig{}, true},
+		"json tag":        {"name: BigName", BigConfig{Str: "BigName"}, false},
+		"int16":           {"integer16: 25", BigConfig{Integer16: 25}, false},
+		"duration number": {"timeout: 5000000000", BigConfig{Timeout: 5 * time.Second}, false},
+		"duration string": {"timeout: 5s", BigConfig{Timeout: 5 * time.Second}, false},
+		"bad duration":    {"timeout: s5s", BigConfig{}, true},
+		"not duration":    {"nottimeout: 30SecToAgent", BigConfig{NotTimeout: "30SecToAgent"}, false},
+	}
+
+	for name, tt := range testData {
+		t.Run(name, func(t *testing.T) {
+			RegisterTestingT(t)
+
+			out := BigConfig{}
+			err := parseConfigFromYamlBytes([]byte(tt.input), &out)
+
+			if tt.fail {
+				Expect(err).To(HaveOccurred())
+				return
+			}
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(out).To(Equal(tt.want))
+		})
+	}
+}