From 32aa7270e6f93e56105d992419d0b9d066f4dd4e Mon Sep 17 00:00:00 2001
From: Murat Kabilov <murat@kabilov.com>
Date: Mon, 9 Oct 2017 16:56:27 +0200
Subject: [PATCH] Use round-robin strategy while assigning workers

---
 pkg/controller/controller.go |  3 +++
 pkg/controller/util.go       | 16 ++++++++++++++--
 pkg/controller/util_test.go  |  4 ++--
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/pkg/controller/controller.go b/pkg/controller/controller.go
index 49fa15ccc..7f5315e27 100644
--- a/pkg/controller/controller.go
+++ b/pkg/controller/controller.go
@@ -30,6 +30,8 @@ type Controller struct {
 
 	stopCh chan struct{}
 
+	curWorkerID    uint32 //initialized with 0
+	clusterWorkers map[spec.NamespacedName]uint32
 	clustersMu     sync.RWMutex
 	clusters       map[spec.NamespacedName]*cluster.Cluster
 	clusterLogs    map[spec.NamespacedName]ringlog.RingLogger
@@ -54,6 +56,7 @@ func NewController(controllerConfig *spec.ControllerConfig) *Controller {
 		config:         *controllerConfig,
 		opConfig:       &config.Config{},
 		logger:         logger.WithField("pkg", "controller"),
+		clusterWorkers: make(map[spec.NamespacedName]uint32),
 		clusters:       make(map[spec.NamespacedName]*cluster.Cluster),
 		clusterLogs:    make(map[spec.NamespacedName]ringlog.RingLogger),
 		clusterHistory: make(map[spec.NamespacedName]ringlog.RingLogger),
diff --git a/pkg/controller/util.go b/pkg/controller/util.go
index 3f847d224..5f91a8995 100644
--- a/pkg/controller/util.go
+++ b/pkg/controller/util.go
@@ -2,7 +2,6 @@ package controller
 
 import (
 	"fmt"
-	"hash/crc32"
 
 	apiextv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -30,7 +29,20 @@ func (c *Controller) makeClusterConfig() cluster.Config {
 }
 
 func (c *Controller) clusterWorkerID(clusterName spec.NamespacedName) uint32 {
-	return crc32.ChecksumIEEE([]byte(clusterName.String())) % c.opConfig.Workers
+	workerId, ok := c.clusterWorkers[clusterName]
+	if ok {
+		return workerId
+	}
+
+	c.clusterWorkers[clusterName] = c.curWorkerID
+
+	if c.curWorkerID == c.opConfig.Workers-1 {
+		c.curWorkerID = 0
+	} else {
+		c.curWorkerID++
+	}
+
+	return c.clusterWorkers[clusterName]
 }
 
 func (c *Controller) createCRD() error {
diff --git a/pkg/controller/util_test.go b/pkg/controller/util_test.go
index a15ef4744..41b8e2fe1 100644
--- a/pkg/controller/util_test.go
+++ b/pkg/controller/util_test.go
@@ -95,11 +95,11 @@ func TestClusterWorkerID(t *testing.T) {
 	}{
 		{
 			in:       spec.NamespacedName{Namespace: "foo", Name: "bar"},
-			expected: 2,
+			expected: 0,
 		},
 		{
 			in:       spec.NamespacedName{Namespace: "default", Name: "testcluster"},
-			expected: 3,
+			expected: 1,
 		},
 	}
 	for _, test := range testTable {