Remove gocron dependency

background_updater.go

@@ -0,0 +1,24 @@
+package ffclient
+
+import "time"
+
+// backgroundUpdater contains what is needed to manage the
+// background update of the flags.
+type backgroundUpdater struct {
+	ticker      *time.Ticker
+	updaterChan chan struct{}
+}
+
+// newBackgroundUpdater init default value for the ticker and the channel.
+func newBackgroundUpdater(pollInterval int) backgroundUpdater {
+	return backgroundUpdater{
+		ticker:      time.NewTicker(time.Duration(pollInterval) * time.Second),
+		updaterChan: make(chan struct{}),
+	}
+}
+
+// close stop the ticker and close the channel.
+func (bgu *backgroundUpdater) close() {
+	bgu.ticker.Stop()
+	close(bgu.updaterChan)
+}

feature_flag.go

@@ -2,7 +2,6 @@ package ffclient
 
 import (
 	"fmt"
-	"github.com/go-co-op/gocron"
 	"log"
 	"sync"
 	"time"
@@ -35,9 +34,9 @@ func Close() {
 // GoFeatureFlag is the main object of the library
 // it contains the cache, the config and the update.
 type GoFeatureFlag struct {
-	flagUpdater gocron.Scheduler
-	cache       cache.Cache
-	config      Config
+	cache     cache.Cache
+	config    Config
+	bgUpdater backgroundUpdater
 }
 
 // ff is the default object for go-feature-flag
@@ -47,54 +46,55 @@ var onceFF sync.Once
 // New creates a new go-feature-flag instance that retrieve the config from a YAML file
 // and return everything you need to manage your flags.
 func New(config Config) (*GoFeatureFlag, error) {
-	flagUpdater := *gocron.NewScheduler(time.UTC)
-
 	// The default value for poll interval is 60 seconds
 	if config.PollInterval == 0 {
 		config.PollInterval = 60
 	}
 
+	// Check that value is not negative
+	if config.PollInterval < 0 {
+		return nil, fmt.Errorf("%d is not a valid PollInterval value, it need to be > 0", config.PollInterval)
+	}
+
 	goFF := &GoFeatureFlag{
-		cache:       cache.New(config.Logger),
-		flagUpdater: flagUpdater,
-		config:      config,
+		cache:     cache.New(config.Logger),
+		config:    config,
+		bgUpdater: newBackgroundUpdater(config.PollInterval),
 	}
 
-	err := goFF.startUpdater()
+	// fail if we cannot retrieve the flags the 1st time
+	err := retrieveFlagsAndUpdateCache(goFF.config, goFF.cache)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("impossible to retrieve the flags, please check your configuration: %v", err)
 	}
 
+	// start the flag update in background
+	go goFF.startFlagUpdaterDaemon()
+
 	return goFF, nil
 }
 
 func (g *GoFeatureFlag) Close() {
+	// clear the cache
 	g.cache.Close()
-	g.flagUpdater.Stop()
-}
 
-func (g *GoFeatureFlag) startUpdater() error {
-	// fail if we cannot retrieve the flags the 1st time
-	err := retrieveFlagsAndUpdateCache(g.config, g.cache)
-	if err != nil {
-		return fmt.Errorf("impossible to retrieve the flags, please check your configuration: %v", err)
-	}
-
-	if g.config.PollInterval < 0 {
-		return fmt.Errorf("%d is not a valid PollInterval value, it need to be > 0", g.config.PollInterval)
-	}
-
-	// start flag updater
-	_, err = g.flagUpdater.
-		Every(uint64(g.config.PollInterval)).
-		Seconds().
-		Do(retrieveFlagsAndUpdateCache, g.config, g.cache)
+	// stop the background updater
+	g.bgUpdater.close()
+}
 
-	if err != nil {
-		return fmt.Errorf("impossible to launch background updater: %v", err)
+// startFlagUpdaterDaemon is the daemon that refresh the cache every X seconds.
+func (g *GoFeatureFlag) startFlagUpdaterDaemon() {
+	for {
+		select {
+		case <-g.bgUpdater.ticker.C:
+			err := retrieveFlagsAndUpdateCache(g.config, g.cache)
+			if err != nil && g.config.Logger != nil {
+				g.config.Logger.Printf("[%v] error while updating the cache: %v\n", time.Now().Format(time.RFC3339), err)
+			}
+		case <-g.bgUpdater.updaterChan:
+			return
+		}
 	}
-	g.flagUpdater.StartAsync()
-	return nil
 }
 
 // retrieveFlagsAndUpdateCache is called every X seconds to refresh the cache flag.

feature_flag_test.go

@@ -3,9 +3,11 @@ package ffclient
 import (
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/stretchr/testify/assert"
+	"io/ioutil"
 	"log"
 	"os"
 	"testing"
+	"time"
 
 	"github.com/thomaspoignant/go-feature-flag/ffuser"
 )
@@ -85,3 +87,41 @@ func Test2GoFeatureFlagInstance(t *testing.T) {
 	hasTestFlagClient2, _ := gffClient2.BoolVariation("test-flag", user, false)
 	assert.False(t, hasTestFlagClient2, "User should have test flag")
 }
+
+func TestUpdateFlag(t *testing.T) {
+	initialFileContent := `test-flag:
+  rule: key eq "random-key"
+  percentage: 100
+  true: true
+  false: false
+  default: false`
+
+	flagFile, _ := ioutil.TempFile("", "")
+	_ = ioutil.WriteFile(flagFile.Name(), []byte(initialFileContent), 0600)
+
+	gffClient1, _ := New(Config{
+		PollInterval: 1,
+		Retriever:    &FileRetriever{Path: flagFile.Name()},
+	})
+	defer gffClient1.Close()
+
+	flagValue, _ := gffClient1.BoolVariation("test-flag", ffuser.NewUser("random-key"), false)
+	assert.True(t, flagValue)
+
+	updatedFileContent := `test-flag:
+  rule: key eq "random-key2"
+  percentage: 100
+  true: true
+  false: false
+  default: false`
+
+	_ = ioutil.WriteFile(flagFile.Name(), []byte(updatedFileContent), 0600)
+
+	flagValue, _ = gffClient1.BoolVariation("test-flag", ffuser.NewUser("random-key"), false)
+	assert.True(t, flagValue)
+
+	time.Sleep(2 * time.Second)
+
+	flagValue, _ = gffClient1.BoolVariation("test-flag", ffuser.NewUser("random-key"), false)
+	assert.False(t, flagValue)
+}

go.mod

@@ -6,7 +6,6 @@ require (
 	github.com/antlr/antlr4 v0.0.0-20201206235148-c87e55b61113 // indirect
 	github.com/aws/aws-sdk-go v1.36.19
 	github.com/blang/semver v3.5.1+incompatible // indirect
-	github.com/go-co-op/gocron v0.4.0
 	github.com/google/go-cmp v0.5.4
 	github.com/nikunjy/rules v0.0.0-20200120082459-0b7c4dc9dc86
 	github.com/stretchr/testify v1.6.1

go.sum

@@ -6,8 +6,6 @@ github.com/blang/semver v3.5.1+incompatible h1:cQNTCjp13qL8KC3Nbxr/y2Bqb63oX6wdn
 github.com/blang/semver v3.5.1+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/go-co-op/gocron v0.4.0 h1:MO9iUktaVn03seJUDGEelPGL3SME9P+Ot9VdTAdorQw=
-github.com/go-co-op/gocron v0.4.0/go.mod h1:6Btk4lVj3bnFAgbVfr76W8impTyhYrEi1pV5Pt4Tp/M=
 github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/jmespath/go-jmespath v0.4.0 h1:BEgLn5cpjn8UN1mAw4NjwDrS35OdebyEtFe+9YPoQUg=
@@ -20,8 +18,6 @@ github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 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=
-github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
@@ -40,8 +36,6 @@ golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IV
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=

internal/cache/cache.go

@@ -20,14 +20,14 @@ type Cache interface {
 type cacheImpl struct {
 	Logger     *log.Logger
 	flagsCache map[string]flags.Flag
-	mutex      sync.Mutex
+	mutex      sync.RWMutex
 	waitGroup  sync.WaitGroup
 }
 
 func New(logger *log.Logger) Cache {
 	return &cacheImpl{
 		flagsCache: make(map[string]flags.Flag),
-		mutex:      sync.Mutex{},
+		mutex:      sync.RWMutex{},
 		Logger:     logger,
 		waitGroup:  sync.WaitGroup{},
 	}
@@ -55,8 +55,13 @@ func (c *cacheImpl) UpdateCache(loadedFlags []byte) error {
 }
 
 func (c *cacheImpl) Close() {
+	// Wait for the logs to finish
 	c.waitGroup.Wait()
+
+	// Clear the cache
+	c.mutex.Lock()
 	c.flagsCache = nil
+	c.mutex.Unlock()
 }
 
 func (c *cacheImpl) getCacheCopy() map[string]flags.Flag {
@@ -68,6 +73,9 @@ func (c *cacheImpl) getCacheCopy() map[string]flags.Flag {
 }
 
 func (c *cacheImpl) GetFlag(key string) (flags.Flag, error) {
+	c.mutex.RLock()
+	defer c.mutex.RUnlock()
+
 	if c.flagsCache == nil {
 		return flags.Flag{}, errors.New("impossible to read the toggle before the initialisation")
 	}
@@ -103,7 +111,7 @@ func (c *cacheImpl) logFlagChanges(oldCache map[string]flags.Flag, newCache map[
 			}
 		} else if !cmp.Equal(oldCache[key], newCache[key]) {
 			// key has changed in cache
-			c.Logger.Printf("[%v] flag %s updated, old=[%v], new=[%v]\n", date, key, c.flagsCache[key], newCache[key])
+			c.Logger.Printf("[%v] flag %s updated, old=[%v], new=[%v]\n", date, key, oldCache[key], newCache[key])
 		}
 	}
 

internal/cache/cache_test.go

@@ -200,7 +200,7 @@ add-test-flag:
 
 			fCache := cacheImpl{
 				flagsCache: oldValue,
-				mutex:      sync.Mutex{},
+				mutex:      sync.RWMutex{},
 				Logger:     log.New(logOutput, "", 0),
 				waitGroup:  sync.WaitGroup{},
 			}

variation_test.go

@@ -2,13 +2,11 @@ package ffclient
 
 import (
 	"errors"
-	"github.com/go-co-op/gocron"
 	"github.com/google/go-cmp/cmp"
 	"github.com/stretchr/testify/assert"
 	"io/ioutil"
 	"log"
 	"testing"
-	"time"
 
 	"github.com/thomaspoignant/go-feature-flag/ffuser"
 	"github.com/thomaspoignant/go-feature-flag/internal/cache"
@@ -168,8 +166,8 @@ func TestBoolVariation(t *testing.T) {
 			logger := log.New(file, "", 0)
 
 			ff = &GoFeatureFlag{
-				flagUpdater: *gocron.NewScheduler(time.UTC),
-				cache:       tt.args.cacheMock,
+				bgUpdater: newBackgroundUpdater(5),
+				cache:     tt.args.cacheMock,
 				config: Config{
 					PollInterval: 0,
 					Logger:       logger,
@@ -330,8 +328,8 @@ func TestFloat64Variation(t *testing.T) {
 			logger := log.New(file, "", 0)
 
 			ff = &GoFeatureFlag{
-				flagUpdater: *gocron.NewScheduler(time.UTC),
-				cache:       tt.args.cacheMock,
+				bgUpdater: newBackgroundUpdater(5),
+				cache:     tt.args.cacheMock,
 				config: Config{
 					PollInterval: 0,
 					Logger:       logger,
@@ -492,8 +490,8 @@ func TestJSONArrayVariation(t *testing.T) {
 			logger := log.New(file, "", 0)
 
 			ff = &GoFeatureFlag{
-				flagUpdater: *gocron.NewScheduler(time.UTC),
-				cache:       tt.args.cacheMock,
+				bgUpdater: newBackgroundUpdater(5),
+				cache:     tt.args.cacheMock,
 				config: Config{
 					PollInterval: 0,
 					Logger:       logger,
@@ -654,8 +652,8 @@ func TestJSONVariation(t *testing.T) {
 			logger := log.New(file, "", 0)
 
 			ff = &GoFeatureFlag{
-				flagUpdater: *gocron.NewScheduler(time.UTC),
-				cache:       tt.args.cacheMock,
+				bgUpdater: newBackgroundUpdater(5),
+				cache:     tt.args.cacheMock,
 				config: Config{
 					PollInterval: 0,
 					Logger:       logger,
@@ -818,8 +816,8 @@ func TestStringVariation(t *testing.T) {
 			logger := log.New(file, "", 0)
 
 			ff = &GoFeatureFlag{
-				flagUpdater: *gocron.NewScheduler(time.UTC),
-				cache:       tt.args.cacheMock,
+				bgUpdater: newBackgroundUpdater(5),
+				cache:     tt.args.cacheMock,
 				config: Config{
 					PollInterval: 0,
 					Logger:       logger,
@@ -980,8 +978,8 @@ func TestIntVariation(t *testing.T) {
 			logger := log.New(file, "", 0)
 
 			ff = &GoFeatureFlag{
-				flagUpdater: *gocron.NewScheduler(time.UTC),
-				cache:       tt.args.cacheMock,
+				bgUpdater: newBackgroundUpdater(5),
+				cache:     tt.args.cacheMock,
 				config: Config{
 					PollInterval: 0,
 					Logger:       logger,