fix(*): rely only on callbacks to decide which config to write (#79)

jlevesy · Oct 1, 2024 · 01afc6f · 01afc6f
1 parent b3a4bb0
commit 01afc6f
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Showing 5 changed files with 26 additions and 43 deletions.
diff --git a/cmd/main.go b/cmd/main.go
@@ -51,7 +51,7 @@ func run() int {
 
 	reconciller := config.NewReconciller(cfg.configPath, cfg.outputPath)
 
-	if err := reconciller.Reconcile(ctx); err != nil {
+	if err := reconciller.Reconcile(ctx, false); err != nil {
 		klog.ErrorS(err, "Can't perform an initial sync")
 		return 1
 	}
@@ -113,7 +113,7 @@ func run() int {
 			OnStartedLeading: func(ctx context.Context) {
 				klog.Info("Leading, applying leader configuration.")
 
-				if err := reconciller.Reconcile(ctx); err != nil {
+				if err := reconciller.Reconcile(ctx, true); err != nil {
 					klog.ErrorS(err, "Failed to reconcile configurations")
 					return
 				}
@@ -126,7 +126,7 @@ func run() int {
 			OnStoppedLeading: func() {
 				klog.Info("Stopped leading, applying follower configuration.")
 
-				if err := reconciller.Reconcile(ctx); err != nil {
+				if err := reconciller.Reconcile(ctx, false); err != nil {
 					klog.ErrorS(err, "Failed to reconcile configurations")
 					return
 				}
@@ -158,9 +158,7 @@ func run() int {
 		klog.Info("Graceful shutdown, left the election")
 	}()
 
-	reconciller.SetLeaderChecker(elector.Status())
-
-	watcher, err := watcher.New(filepath.Dir(cfg.configPath), reconciller, notifier)
+	watcher, err := watcher.New(filepath.Dir(cfg.configPath), reconciller, notifier, elector.Status())
 	if err != nil {
 		klog.ErrorS(err, "Can't create the watcher")
 		return 1

diff --git a/config/reconcile.go b/config/reconcile.go
@@ -4,15 +4,11 @@ import (
 	"context"
 
 	"github.com/imdario/mergo"
-	"github.com/jlevesy/prometheus-elector/election"
-	"k8s.io/klog/v2"
 )
 
 type Reconciler struct {
 	sourcePath string
 	outputPath string
-
-	leaderChecker election.LeaderChecker
 }
 
 func NewReconciller(src, out string) *Reconciler {
@@ -22,20 +18,15 @@ func NewReconciller(src, out string) *Reconciler {
 	}
 }
 
-func (r *Reconciler) SetLeaderChecker(lc election.LeaderChecker) {
-	r.leaderChecker = lc
-}
-
-func (r *Reconciler) Reconcile(ctx context.Context) error {
+func (r *Reconciler) Reconcile(ctx context.Context, leader bool) error {
 	cfg, err := loadConfiguration(r.sourcePath)
 	if err != nil {
 		return err
 	}
 
 	targetCfg := cfg.Follower
 
-	if cfg.Leader != nil && r.leaderChecker != nil && r.leaderChecker.IsLeader() {
-		klog.Info("Writing leader configuration")
+	if leader {
 		if err := mergo.Merge(
 			&targetCfg,
 			cfg.Leader,

diff --git a/config/reconcile_test.go b/config/reconcile_test.go
@@ -8,7 +8,6 @@ import (
 	"testing"
 
 	"github.com/jlevesy/prometheus-elector/config"
-	"github.com/jlevesy/prometheus-elector/election"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -18,27 +17,21 @@ const fileName = "prometheus.yaml"
 func TestReconciler(t *testing.T) {
 	for _, testCase := range []struct {
 		desc           string
-		leaderChecker  election.LeaderChecker
+		isLeader       bool
 		inputPath      string
 		wantError      error
 		wantResultPath string
 	}{
-		{
-			desc:           "follower without leader checker",
-			inputPath:      "./testdata/config.yaml",
-			leaderChecker:  nil,
-			wantResultPath: "./testdata/follower_no_leader_result.yaml",
-		},
 		{
 			desc:           "follower",
 			inputPath:      "./testdata/config.yaml",
-			leaderChecker:  leaderCheckerFunc(func() bool { return false }),
+			isLeader:       false,
 			wantResultPath: "./testdata/follower_no_leader_result.yaml",
 		},
 		{
 			desc:           "leader",
 			inputPath:      "./testdata/config.yaml",
-			leaderChecker:  leaderCheckerFunc(func() bool { return true }),
+			isLeader:       true,
 			wantResultPath: "./testdata/leader_result.yaml",
 		},
 		{
@@ -63,9 +56,7 @@ func TestReconciler(t *testing.T) {
 				)
 			)
 
-			reconciler.SetLeaderChecker(testCase.leaderChecker)
-
-			err := reconciler.Reconcile(ctx)
+			err := reconciler.Reconcile(ctx, testCase.isLeader)
 			if testCase.wantError != nil {
 				assert.Equal(t, testCase.wantError, err)
 				return
@@ -82,7 +73,3 @@ func TestReconciler(t *testing.T) {
 		})
 	}
 }
-
-type leaderCheckerFunc func() bool
-
-func (l leaderCheckerFunc) IsLeader() bool { return l() }
diff --git a/watcher/watcher.go b/watcher/watcher.go
@@ -9,16 +9,18 @@ import (
 	"k8s.io/klog/v2"
 
 	"github.com/jlevesy/prometheus-elector/config"
+	"github.com/jlevesy/prometheus-elector/election"
 	"github.com/jlevesy/prometheus-elector/notifier"
 )
 
 type FileWatcher struct {
-	fsWatcher  *fsnotify.Watcher
-	reconciler *config.Reconciler
-	notifier   notifier.Notifier
+	fsWatcher     *fsnotify.Watcher
+	reconciler    *config.Reconciler
+	leaderChecker election.LeaderChecker
+	notifier      notifier.Notifier
 }
 
-func New(path string, reconciler *config.Reconciler, notifier notifier.Notifier) (*FileWatcher, error) {
+func New(path string, reconciler *config.Reconciler, notifier notifier.Notifier, leaderChecker election.LeaderChecker) (*FileWatcher, error) {
 	watcher, err := fsnotify.NewWatcher()
 	if err != nil {
 		return nil, fmt.Errorf("unable to create fsnotify watcher: %w", err)
@@ -31,9 +33,10 @@ func New(path string, reconciler *config.Reconciler, notifier notifier.Notifier)
 	klog.InfoS("Watching config directory", "path", path)
 
 	return &FileWatcher{
-		fsWatcher:  watcher,
-		reconciler: reconciler,
-		notifier:   notifier,
+		fsWatcher:     watcher,
+		leaderChecker: leaderChecker,
+		reconciler:    reconciler,
+		notifier:      notifier,
 	}, nil
 }
 
@@ -56,7 +59,7 @@ func (f *FileWatcher) Watch(ctx context.Context) error {
 
 			klog.Info("Configuration changed, reconciling...")
 
-			if err := f.reconciler.Reconcile(ctx); err != nil {
+			if err := f.reconciler.Reconcile(ctx, f.leaderChecker.IsLeader()); err != nil {
 				klog.ErrorS(err, "Reconciler reported an error")
 				continue
 			}

diff --git a/watcher/watcher_test.go b/watcher/watcher_test.go
@@ -60,7 +60,7 @@ func TestFileWatcher(t *testing.T) {
 	err := simulateConfigmapWrite(dir, fileName, []byte(defaultConfig))
 	require.NoError(t, err)
 
-	watcher, err := watcher.New(dir, reconciler, notifierFunc(notifier))
+	watcher, err := watcher.New(dir, reconciler, notifierFunc(notifier), leaderCheckerFunc(func() bool { return false }))
 	require.NoError(t, err)
 
 	defer watcher.Close()
@@ -113,3 +113,7 @@ type notifierFunc func() error
 func (n notifierFunc) Notify(context.Context) error {
 	return n()
 }
+
+type leaderCheckerFunc func() bool
+
+func (l leaderCheckerFunc) IsLeader() bool { return l() }