Allow reading from env file

CHANGELOG.md

@@ -1,3 +1,7 @@
+# v1.3.0 (Jan 9, 2023)
+
+1.  Allow reading environment variables from file or os.
+
 # v1.2.0 (Jan 8, 2023)
 
 1.  Allow converting config to map.

config.go

@@ -27,9 +27,11 @@ import (
 	"io/ioutil"
 	"os"
 	"strings"
+	"time"
 
 	"github.com/fsnotify/fsnotify"
 	"github.com/go-ini/ini"
+	"github.com/joho/godotenv"
 	"github.com/xybor-x/xyerror"
 	"github.com/xybor-x/xylock"
 	"github.com/xybor-x/xylog"
@@ -43,6 +45,7 @@ const (
 	UnknownFormat Format = iota
 	JSON
 	INI
+	ENV
 )
 
 var loggerName = "xybor.xyplatform.xyconfig"
@@ -51,6 +54,7 @@ var logger = xylog.GetLogger(loggerName)
 var extensions = map[string]Format{
 	".json": JSON,
 	".ini":  INI,
+	".env":  ENV,
 }
 
 // Event represents for a changes in the config.
@@ -83,6 +87,9 @@ type Config struct {
 	// watcher tracks changes of files.
 	watcher *fsnotify.Watcher
 
+	// envWatcher tracks the waching of environment variables.
+	envWatcher *time.Timer
+
 	// lock avoids race condition.
 	lock *xylock.RWLock
 }
@@ -143,6 +150,12 @@ func (c *Config) CloseWatcher() error {
 		err = c.watcher.Close()
 		c.watcher = nil
 	}
+
+	if c.envWatcher != nil {
+		c.envWatcher.Stop()
+		c.envWatcher = nil
+	}
+
 	return err
 }
 
@@ -288,13 +301,29 @@ func (c *Config) ReadINI(b []byte) error {
 	return nil
 }
 
+// ReadENV reads the config values from a byte array under ENV format.
+func (c *Config) ReadENV(b []byte) error {
+	var envmap, err = godotenv.Unmarshal(string(b))
+	if err != nil {
+		return ConfigError.New(err)
+	}
+
+	for k, v := range envmap {
+		c.Set(k, v, false)
+	}
+
+	return nil
+}
+
 // ReadBytes reads the config values from a bytes array under any format.
 func (c *Config) ReadBytes(format Format, b []byte) error {
 	switch format {
 	case JSON:
 		return c.ReadJSON(b)
 	case INI:
 		return c.ReadINI(b)
+	case ENV:
+		return c.ReadENV(b)
 	default:
 		return FormatError.New("unsupported format")
 	}
@@ -337,6 +366,27 @@ func (c *Config) ReadFile(filename string, watch bool) error {
 	return nil
 }
 
+// LoadEnv loads all environment variables and watch for their changes every
+// duration. Set the duration as zero if no need to watch the change.
+func (c *Config) LoadEnv(d time.Duration) error {
+	var envs = os.Environ()
+	for i := range envs {
+		var key, value, found = strings.Cut(envs[i], "=")
+		if !found {
+			return FormatError.Newf("invalid environment variable %s", envs[i])
+		}
+		c.Set(key, value, false)
+	}
+
+	if d != 0 {
+		c.lock.Lock()
+		c.envWatcher = time.AfterFunc(d, func() { c.LoadEnv(d) })
+		c.lock.Unlock()
+	}
+
+	return nil
+}
+
 // Get returns the value assigned with the key. The latter returned value is
 // false if they key doesn't exist.
 func (c *Config) Get(key string) (Value, bool) {

config_test.go

@@ -22,6 +22,7 @@ package xyconfig_test
 
 import (
 	"io/ioutil"
+	"os"
 	"testing"
 	"time"
 
@@ -150,6 +151,15 @@ func TestConfigReadByteINI(t *testing.T) {
 	xycond.ExpectTrue(cfg.MustGet("buzz.nil").IsNil()).Test(t)
 }
 
+func TestConfigReadByteENV(t *testing.T) {
+	var cfg = xyconfig.GetConfig(t.Name())
+	cfg.ReadBytes(xyconfig.ENV, []byte("fizz=bar\nbizz=bemm\nnil="))
+
+	xycond.ExpectEqual(cfg.MustGet("fizz").MustString(), "bar").Test(t)
+	xycond.ExpectEqual(cfg.MustGet("bizz").MustString(), "bemm").Test(t)
+	xycond.ExpectTrue(cfg.MustGet("nil").IsNil()).Test(t)
+}
+
 func TestConfigReadByteUnknown(t *testing.T) {
 	var cfg = xyconfig.GetConfig(t.Name())
 	var err = cfg.ReadBytes(xyconfig.UnknownFormat, []byte(""))
@@ -192,6 +202,20 @@ func TestConfigReadFileWithChange(t *testing.T) {
 	xycond.ExpectEqual(cfg.MustGet("foo").MustString(), "buzz").Test(t)
 }
 
+func TestConfigLoadEnvWithChange(t *testing.T) {
+	os.Setenv("foo", "bar")
+
+	var cfg = xyconfig.GetConfig(t.Name())
+	defer cfg.CloseWatcher()
+
+	cfg.LoadEnv(time.Millisecond)
+	xycond.ExpectEqual(cfg.MustGet("foo").MustString(), "bar").Test(t)
+
+	os.Setenv("foo", "buzz")
+	time.Sleep(2 * time.Millisecond)
+	xycond.ExpectEqual(cfg.MustGet("foo").MustString(), "buzz").Test(t)
+}
+
 func TestConfigReadFileWithErrorFileAfterChange(t *testing.T) {
 	ioutil.WriteFile(t.Name()+".json", []byte(`{"foo": "bar"}`), 0644)
 

go.mod

@@ -5,6 +5,7 @@ go 1.18
 require (
 	github.com/fsnotify/fsnotify v1.6.0
 	github.com/go-ini/ini v1.67.0
+	github.com/joho/godotenv v1.4.0
 	github.com/xybor-x/xycond v1.0.0
 	github.com/xybor-x/xyerror v1.0.5
 	github.com/xybor-x/xylock v0.0.1

go.sum

@@ -5,6 +5,8 @@ github.com/fsnotify/fsnotify v1.6.0 h1:n+5WquG0fcWoWp6xPWfHdbskMCQaFnG6PfBrh1Ky4
 github.com/fsnotify/fsnotify v1.6.0/go.mod h1:sl3t1tCWJFWoRz9R8WJCbQihKKwmorjAbSClcnxKAGw=
 github.com/go-ini/ini v1.67.0 h1:z6ZrTEZqSWOTyH2FlglNbNgARyHG8oLW9gMELqKr06A=
 github.com/go-ini/ini v1.67.0/go.mod h1:ByCAeIL28uOIIG0E3PJtZPDL8WnHpFKFOtgjp+3Ies8=
+github.com/joho/godotenv v1.4.0 h1:3l4+N6zfMWnkbPEXKng2o2/MR5mSwTrBih4ZEkkz1lg=
+github.com/joho/godotenv v1.4.0/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -16,8 +18,6 @@ github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKs
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/xybor-x/xycond v1.0.0 h1:RJippg8hc0/HcEerJQrddHok7iaZUyLGrjN6Pbpe8u8=
 github.com/xybor-x/xycond v1.0.0/go.mod h1:b/NXVIxFPWvGyHAAdkNooYSw9IpqF04VuW2+i7iE8sU=
-github.com/xybor-x/xyerror v1.0.0 h1:tFqmi+SOnNrUaL1FDzp5qr/Ed0SY0tUfm1inmFMrt7g=
-github.com/xybor-x/xyerror v1.0.0/go.mod h1:2P0SjxOPAkdllEpPhmlWYVOGKDVxzwl/RkmLcc2i9Os=
 github.com/xybor-x/xyerror v1.0.5 h1:SiC0OWcVDvb3MwLMTFWCvnrACYln3KbYkhr9nehtfV0=
 github.com/xybor-x/xyerror v1.0.5/go.mod h1:2P0SjxOPAkdllEpPhmlWYVOGKDVxzwl/RkmLcc2i9Os=
 github.com/xybor-x/xylock v0.0.1 h1:/LhbJb6WJkUW+xE4/bBpIC76BKrbgnayiId6LdouqUw=