Merge pull request #7 from jparise/regexp

Add regexp.Regexp support

README.md

@@ -20,7 +20,7 @@ fig is a tiny library for loading an application's config file and its environme
 - Define your **configuration**, **validations** and **defaults** in a single location
 - Optionally **load from the environment** as well
 - Only **3** external dependencies
-- Full support for`time.Time` & `time.Duration`
+- Full support for`time.Time`, `time.Duration` & `regexp.Regexp`
 - Tiny API
 - Decoders for `.yaml`, `.json` and `.toml` files
 
@@ -64,8 +64,9 @@ type Config struct {
     Cleanup time.Duration `fig:"cleanup" default:"30m"`
   }
   Logger struct {
-    Level string `fig:"level" default:"info"`
-    Trace bool   `fig:"trace"`
+    Level   string         `fig:"level" default:"info"`
+    Pattern *regexp.Regexp `fig:"pattern" default:".*"`
+    Trace   bool           `fig:"trace"`
   }
 }
 
@@ -75,7 +76,7 @@ func main() {
   // handle your err
 
   fmt.Printf("%+v\n", cfg)
-  // Output: {Build:2019-12-25 00:00:00 +0000 UTC Server:{Host:127.0.0.1 Ports:[8080] Cleanup:1h0m0s} Logger:{Level:warn Trace:true}}
+  // Output: {Build:2019-12-25 00:00:00 +0000 UTC Server:{Host:127.0.0.1 Ports:[8080] Cleanup:1h0m0s} Logger:{Level:warn Pattern:.* Trace:true}}
 }
 ```
 

doc.go

@@ -188,9 +188,10 @@ See example below to help understand:
       I interface{} `validate:"required"`
       J interface{} `validate:"required"`
     } `validate:"required"`
-    K *[]bool    `validate:"required"`
-    L []uint     `validate:"required"`
-    M *time.Time `validate:"required"`
+    K *[]bool        `validate:"required"`
+    L []uint         `validate:"required"`
+    M *time.Time     `validate:"required"`
+    N *regexp.Regexp `validate:"required"`
   }
 
   var cfg Config
@@ -206,7 +207,7 @@ See example below to help understand:
 
   err := fig.Load(&cfg)
   fmt.Print(err)
-  // A: required, B: required, C: required, D: required, E: required, G: required, H.J: required, K: required, M: required
+  // A: required validation failed, B: required validation failed, C: required validation failed, D: required validation failed, E: required validation failed, G: required validation failed, H.J: required validation failed, K: required validation failed, M: required validation failed, N: required validation failed
 
 Default
 
@@ -224,6 +225,7 @@ A default value can be set for the following types:
   all basic types except bool and complex
   time.Time
   time.Duration
+  *regexp.Regexp
   slices (of above types)
 
 Successive elements of slice defaults should be separated by a comma. The entire slice can optionally be enclosed in square brackets:

examples/config/config.yaml

@@ -7,6 +7,7 @@ server:
 
 logger:
   level: debug
+  pattern: '[a-z]+'
 
 certificate:
   version: 1

examples/config/config_test.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"fmt"
+	"regexp"
 	"time"
 
 	"github.com/kkyr/fig"
@@ -18,7 +19,8 @@ type Config struct {
 		WriteTimeout time.Duration `fig:"write_timeout" default:"30s"`
 	} `fig:"server"`
 	Logger struct {
-		Level string `fig:"level" default:"info"`
+		Level   string         `fig:"level" default:"info"`
+		Pattern *regexp.Regexp `fig:"pattern" default:".*"`
 	} `fig:"logger"`
 	Certificate struct {
 		Version    int       `fig:"version"`
@@ -40,6 +42,7 @@ func ExampleLoad() {
 	fmt.Println(cfg.Server.ReadTimeout)
 	fmt.Println(cfg.Server.WriteTimeout)
 	fmt.Println(cfg.Logger.Level)
+	fmt.Println(cfg.Logger.Pattern)
 	fmt.Println(cfg.Certificate.Version)
 	fmt.Println(cfg.Certificate.DNSNames)
 	fmt.Println(cfg.Certificate.Expiration.Format("2006-01-02"))
@@ -51,6 +54,7 @@ func ExampleLoad() {
 	// 1m0s
 	// 30s
 	// debug
+	// [a-z]+
 	// 1
 	// [kkyr kkyr.io]
 	// 2020-12-01

fig.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -153,6 +154,7 @@ func (f *fig) decodeMap(m map[string]interface{}, result interface{}) error {
 		DecodeHook: mapstructure.ComposeDecodeHookFunc(
 			mapstructure.StringToTimeDurationHookFunc(),
 			mapstructure.StringToTimeHookFunc(f.timeLayout),
+			stringToRegexpHookFunc(),
 		),
 	})
 	if err != nil {
@@ -161,6 +163,22 @@ func (f *fig) decodeMap(m map[string]interface{}, result interface{}) error {
 	return dec.Decode(m)
 }
 
+// stringToRegexpHookFunc returns a DecodeHookFunc that converts strings to regexp.Regexp.
+func stringToRegexpHookFunc() mapstructure.DecodeHookFunc {
+	return func(
+		f reflect.Type,
+		t reflect.Type,
+		data interface{}) (interface{}, error) {
+		if f.Kind() != reflect.String {
+			return data, nil
+		}
+		if t != reflect.TypeOf(&regexp.Regexp{}) {
+			return data, nil
+		}
+		return regexp.Compile(data.(string))
+	}
+}
+
 // processCfg processes a cfg struct after it has been loaded from
 // the config file, by validating required fields and setting defaults
 // where applicable.
@@ -289,6 +307,12 @@ func (f *fig) setValue(fv reflect.Value, val string) error {
 				return err
 			}
 			fv.Set(reflect.ValueOf(t))
+		} else if _, ok := fv.Interface().(regexp.Regexp); ok {
+			re, err := regexp.Compile(val)
+			if err != nil {
+				return err
+			}
+			fv.Set(reflect.ValueOf(*re))
 		} else {
 			return fmt.Errorf("unsupported type %s", fv.Kind())
 		}

fig_test.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"regexp"
 	"strings"
 	"testing"
 	"time"
@@ -221,8 +222,9 @@ func Test_fig_Load_Defaults(t *testing.T) {
 					Host   string `fig:"host" default:"127.0.0.1"`
 					Ports  []int  `fig:"ports" default:"[80,443]"`
 					Logger struct {
-						LogLevel   string `fig:"log_level" default:"info"`
-						Production bool   `fig:"production"`
+						LogLevel   string         `fig:"log_level" default:"info"`
+						Pattern    *regexp.Regexp `fig:"pattern" default:".*"`
+						Production bool           `fig:"production"`
 						Metadata   struct {
 							Keys []string `fig:"keys" default:"[ts]"`
 						}
@@ -236,6 +238,7 @@ func Test_fig_Load_Defaults(t *testing.T) {
 				want.Host = "0.0.0.0"
 				want.Ports = []int{80, 443}
 				want.Logger.LogLevel = "debug"
+				want.Logger.Pattern = regexp.MustCompile(".*")
 				want.Logger.Production = false
 				want.Logger.Metadata.Keys = []string{"ts"}
 				want.Application.BuildDate = time.Date(2020, 1, 1, 12, 0, 0, 0, time.UTC)
@@ -1014,6 +1017,35 @@ func Test_fig_setValue(t *testing.T) {
 		}
 	})
 
+	t.Run("regexp", func(t *testing.T) {
+		var re regexp.Regexp
+		fv := reflect.ValueOf(&re).Elem()
+
+		err := fig.setValue(fv, "[a-z]+")
+		if err != nil {
+			t.Fatalf("unexpected err: %v", err)
+		}
+
+		want, err := regexp.Compile("[a-z]+")
+		if err != nil {
+			t.Fatalf("error parsing time: %v", err)
+		}
+
+		if re.String() != want.String() {
+			t.Fatalf("want %v, got %v", want, re)
+		}
+	})
+
+	t.Run("bad regexp", func(t *testing.T) {
+		var re regexp.Regexp
+		fv := reflect.ValueOf(&re).Elem()
+
+		err := fig.setValue(fv, "[a-")
+		if err == nil {
+			t.Fatalf("expected err")
+		}
+	})
+
 	t.Run("interface returns error", func(t *testing.T) {
 		var i interface{}
 		fv := reflect.ValueOf(i)
@@ -1089,6 +1121,15 @@ func Test_fig_setSlice(t *testing.T) {
 			},
 			Val: "[2019-12-25T10:30:30Z,2020-01-01T00:00:00Z]",
 		},
+		{
+			Name:    "regexps",
+			InSlice: &[]*regexp.Regexp{},
+			WantSlice: &[]*regexp.Regexp{
+				regexp.MustCompile("[a-z]+"),
+				regexp.MustCompile(".*"),
+			},
+			Val: "[[a-z]+,.*]",
+		},
 	} {
 		t.Run(tc.Val, func(t *testing.T) {
 			in := reflect.ValueOf(tc.InSlice).Elem()

util_test.go

@@ -3,6 +3,7 @@ package fig
 import (
 	"path/filepath"
 	"reflect"
+	"regexp"
 	"testing"
 	"time"
 )
@@ -137,6 +138,22 @@ func Test_isZero(t *testing.T) {
 		}
 	})
 
+	t.Run("zero regexp is zero", func(t *testing.T) {
+		var re *regexp.Regexp
+
+		if isZero(reflect.ValueOf(re)) == false {
+			t.Fatalf("isZero == false")
+		}
+	})
+
+	t.Run("non-zero regexp is not zero", func(t *testing.T) {
+		re := regexp.MustCompile(".*")
+
+		if isZero(reflect.ValueOf(re)) == true {
+			t.Fatalf("isZero == true")
+		}
+	})
+
 	t.Run("reflect invalid is zero", func(t *testing.T) {
 		var x interface{}