Add test for kube-utils peer list

- In parallel on several goroutines, randomly add and remove peers.
 - Maintain the test's own idea of current state.
 - Check that the test's state and kube-utils' state are consistent.

prog/kube-utils/peerlist_test.go

@@ -0,0 +1,177 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+const (
+	peerName1 = "01:00:00:00:00:00"
+	peerName2 = "02:00:00:00:00:00"
+	peerName3 = "03:00:00:00:00:00"
+	nodeName1 = "fake-node-1"
+	nodeName2 = "fake-node-2"
+
+	testIters = 1000
+)
+
+func TestPeerListBasic(t *testing.T) {
+	c := NewSimpleClientset()
+
+	cml := newConfigMapAnnotations(configMapNamespace, configMapName, c)
+	err := cml.Init()
+	require.NoError(t, err)
+
+	list1, err := addMyselfToPeerList(cml, c, peerName1, nodeName1)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(list1.Peers))
+	list2, err := addMyselfToPeerList(cml, c, peerName2, nodeName2)
+	require.NoError(t, err)
+	require.Equal(t, 2, len(list2.Peers))
+
+	check1, err := checkIamInPeerList(cml, c, peerName1)
+	require.NoError(t, err)
+	require.Equal(t, true, check1)
+	check3, err := checkIamInPeerList(cml, c, peerName3)
+	require.NoError(t, err)
+	require.Equal(t, false, check3)
+
+	storedPeerList, err := cml.GetPeerList()
+	require.NoError(t, err)
+
+	storedPeerList.remove(peerName1)
+	require.Equal(t, 1, len(storedPeerList.Peers))
+	err = cml.UpdatePeerList(*storedPeerList)
+	require.NoError(t, err)
+	check1, err = checkIamInPeerList(cml, c, peerName1)
+	require.NoError(t, err)
+	require.Equal(t, false, check1)
+}
+
+// Run function _f_ _iterations_ times, in _concurrency_
+// number of goroutines
+func doConcurrentIterations(iterations, concurrency int, f func(int)) {
+	iterationsPerThread := iterations / concurrency
+
+	wg := sync.WaitGroup{}
+	for i := 0; i < concurrency; i++ {
+		wg.Add(1)
+		go func(j int) {
+			defer wg.Done()
+			for k := 0; k < iterationsPerThread; k++ {
+				f((j * iterationsPerThread) + k)
+			}
+		}(i)
+	}
+	wg.Wait()
+}
+
+func TestPeerListFuzz(t *testing.T) {
+	const (
+		testIters   = 1000
+		maxNodes    = 100
+		concurrency = 5
+	)
+	peerName := func(i int) string { return fmt.Sprintf("%02d:00:00:02:00:00", i) }
+	nodeName := func(i int) string { return fmt.Sprintf("node%d", i) }
+
+	stateLock := sync.Mutex{}
+	nodes := []int{}
+	nodeMap := map[int]bool{} // true if an operation is pending
+
+	c := NewSimpleClientset()
+
+	addNode := func() {
+		i := rand.Intn(maxNodes)
+		// add to test state first, then to Kubernetes
+		stateLock.Lock()
+		pending, found := nodeMap[i]
+		if !found {
+			nodes = append(nodes, i)
+		}
+		nodeMap[i] = true
+		stateLock.Unlock()
+		if pending { // someone else is adding or deleting this node
+			return
+		}
+
+		cml := newConfigMapAnnotations(configMapNamespace, configMapName, c)
+		err := cml.Init()
+		require.NoError(t, err)
+		_, err = addMyselfToPeerList(cml, c, peerName(i), nodeName(i))
+		require.NoError(t, err)
+
+		stateLock.Lock()
+		nodeMap[i] = false
+		stateLock.Unlock()
+	}
+
+	removeNode := func() {
+		stateLock.Lock()
+		if len(nodes) == 0 { // can't remove if there aren't any nodes
+			stateLock.Unlock()
+			return
+		}
+		pos := rand.Intn(len(nodes))
+		i := nodes[pos]
+		if pending, found := nodeMap[i]; found {
+			if pending {
+				stateLock.Unlock()
+				return // someone else is adding or deleting this node
+			}
+			nodeMap[i] = true
+		} else {
+			t.Errorf("missing entry from node map: %d", i)
+		}
+		stateLock.Unlock()
+
+		// remove from Kubernetes first, then from test state
+		cml := newConfigMapAnnotations(configMapNamespace, configMapName, c)
+		err := cml.Init()
+		require.NoError(t, err)
+		storedPeerList, err := cml.GetPeerList()
+		require.NoError(t, err)
+		found := storedPeerList.contains(peerName(i))
+		require.Equal(t, true, found, "peer %d not found in stored list", i)
+		if !found {
+			return
+		}
+		storedPeerList.remove(peerName(i))
+		err = cml.UpdatePeerList(*storedPeerList)
+		require.NoError(t, err)
+
+		stateLock.Lock()
+		delete(nodeMap, i)
+		for pos = 0; pos < len(nodes); pos++ {
+			if nodes[pos] == i {
+				// Remove item from list by swapping it with last and reducing slice length by 1
+				nodes[pos] = nodes[len(nodes)-1]
+				nodes = nodes[:len(nodes)-1]
+				break
+			}
+		}
+		stateLock.Unlock()
+	}
+
+	doConcurrentIterations(testIters, concurrency, func(iteration int) {
+		r := rand.Float32()
+		switch {
+		case 0.0 <= r && r < 0.4:
+			addNode()
+
+		case (0.4 <= r && r < 0.8):
+			removeNode()
+		}
+	})
+
+	cml := newConfigMapAnnotations(configMapNamespace, configMapName, c)
+	err := cml.Init()
+	require.NoError(t, err)
+	storedPeerList, err := cml.GetPeerList()
+	require.NoError(t, err)
+	require.Equal(t, len(storedPeerList.Peers), len(nodes))
+}