add Get helper

.env

@@ -1 +1,2 @@
-VALUE="ok"
+NUM="1"
+STR="hello"

.golangci.yml

@@ -11,6 +11,8 @@ linters:
     - paralleltest
     - gochecknoglobals
     - varnamelen
+    - forcetypeassert
+    - ireturn
 
     - structcheck
     - interfacer
@@ -23,8 +25,12 @@ linters:
     - nosnakecase
     - scopelint
 
-gocyclo:
-  min-complexity: 15
+linters-settings:
+  gocyclo:
+    min-complexity: 15
+
+  cyclop:
+    max-complexity: 20
 
 issues:
   exclude-use-default: false

README.md

@@ -2,6 +2,8 @@
 
 Load the `.env` file from current directory or one of the parent directories, then use it to set the process environment variables.
 
+It also provides a function to parse the value of environment variables, it uses generics so you don't need to cast the value manually.
+
 For usage check the [example](example/basic.go).
 
 About the format of `.env`: [link](https://docs.docker.com/compose/environment-variables/env-file/)

dotenv.go

@@ -23,3 +23,8 @@ func init() {
 
 	lg.Println(msg)
 }
+
+// Get is a shortcut for [lib.Get].
+func Get[T lib.EnvType](name string, defaultVal T) T {
+	return lib.Get(name, defaultVal)
+}

example/basic.go

@@ -2,12 +2,16 @@ package main
 
 import (
 	"fmt"
-	"os"
 
-	_ "github.com/ysmood/dotenv"
+	dotenv "github.com/ysmood/dotenv"
 )
 
 func main() {
-	// It will output the VALUE in "../.env" which is "ok"
-	fmt.Println(os.Getenv("VALUE"))
+	num := dotenv.Get("NUM", 0)
+	str := dotenv.Get("STR", "")
+
+	// It will output the env variables in "../.env"
+	// The output will be:
+	//	2 hello world
+	fmt.Println(num+1, str+" world")
 }

go.mod

@@ -1,5 +1,10 @@
 module github.com/ysmood/dotenv
 
-go 1.20
+go 1.21
 
-require github.com/joho/godotenv v1.5.1
+require (
+	github.com/joho/godotenv v1.5.1
+	github.com/ysmood/got v0.38.2
+)
+
+require github.com/ysmood/gop v0.2.0 // indirect

go.sum

@@ -1,2 +1,6 @@
 github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/ysmood/gop v0.2.0 h1:+tFrG0TWPxT6p9ZaZs+VY+opCvHU8/3Fk6BaNv6kqKg=
+github.com/ysmood/gop v0.2.0/go.mod h1:rr5z2z27oGEbyB787hpEcx4ab8cCiPnKxn0SUHt6xzk=
+github.com/ysmood/got v0.38.2 h1:h2RYvAe5nIK+oBRMLzNIrkZaX5kjmkOBqfRMIsFzLyU=
+github.com/ysmood/got v0.38.2/go.mod h1:W7DdpuX6skL3NszLmAsC5hT7JAhuLZhByVzHTq874Qg=

lib/lib.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strconv"
+	"time"
 
 	"github.com/joho/godotenv"
 )
@@ -45,3 +47,56 @@ func LookupFile(file string) string {
 
 	return ""
 }
+
+type EnvType interface {
+	bool | string | int | float64 | time.Duration
+}
+
+// Get env var with default value.
+func Get[T EnvType](name string, defaultVal T) T {
+	envStr, has := os.LookupEnv(name)
+	if !has {
+		return defaultVal
+	}
+
+	var v any = defaultVal
+
+	switch v.(type) {
+	case bool:
+		b, err := strconv.ParseBool(envStr)
+		if err != nil {
+			panic(err)
+		}
+
+		v = b
+
+	case string:
+		v = envStr
+
+	case int:
+		i, err := strconv.ParseInt(envStr, 10, 64)
+		if err != nil {
+			panic(err)
+		}
+
+		v = int(i)
+
+	case float64:
+		f, err := strconv.ParseFloat(envStr, 64)
+		if err != nil {
+			panic(err)
+		}
+
+		v = f
+
+	case time.Duration:
+		d, err := time.ParseDuration(envStr)
+		if err != nil {
+			panic(err)
+		}
+
+		v = d
+	}
+
+	return v.(T)
+}

lib/lib_test.go

@@ -0,0 +1,30 @@
+package lib_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ysmood/dotenv/lib"
+	"github.com/ysmood/got"
+)
+
+func TestGet(t *testing.T) {
+	g := got.T(t)
+
+	t.Setenv("BOOL", "true")
+	t.Setenv("NUM", "2")
+	t.Setenv("STR", "ok")
+	t.Setenv("FLOAT", "1.2")
+	t.Setenv("DURATION", "1m")
+
+	g.Eq(lib.Get("BOOL", false), true)
+	g.Eq(lib.Get("BOOL_DEFAULT", true), true)
+	g.Eq(lib.Get("NUM", 0), 2)
+	g.Eq(lib.Get("NUM_DEFAULT", 1), 1)
+	g.Eq(lib.Get("STR", ""), "ok")
+	g.Eq(lib.Get("STR_DEFAULT", "yes"), "yes")
+	g.Eq(lib.Get("FLOAT", 0.0), 1.2)
+	g.Eq(lib.Get("FLOAT_DEFAULT", 1.1), 1.1)
+	g.Eq(lib.Get("DURATION", time.Second), time.Minute)
+	g.Eq(lib.Get("DURATION_DEFAULT", time.Hour), time.Hour)
+}

test/basic_test.go

@@ -8,7 +8,7 @@ import (
 )
 
 func TestBasic(t *testing.T) {
-	if os.Getenv("VALUE") != "ok" {
+	if os.Getenv("STR") != "hello" {
 		t.Fail()
 	}
 }