Add auto-demotion after peer inactivity.

tests/functional/proxy_test.go

@@ -82,3 +82,63 @@ func TestProxy(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, len(result.Node.Nodes), 2)
 }
+
+// Create a full cluster, disconnect a peer, wait for autodemotion, wait for autopromotion.
+func TestProxyAutoPromote(t *testing.T) {
+	clusterSize := 10 // DefaultActiveSize + 1
+	_, etcds, err := CreateCluster(clusterSize, &os.ProcAttr{Files: []*os.File{nil, os.Stdout, os.Stderr}}, false)
+	if err != nil {
+		t.Fatal("cannot create cluster")
+	}
+	defer func() {
+		// Wrap this in a closure so that it picks up the updated version of
+		// the "etcds" variable.
+		DestroyCluster(etcds)
+	}()
+
+	c := etcd.NewClient(nil)
+	c.SyncCluster()
+
+	time.Sleep(1 * time.Second)
+
+	// Verify that we have one proxy.
+	result, err := c.Get("_etcd/proxies", false, true)
+	assert.NoError(t, err)
+	assert.Equal(t, len(result.Node.Nodes), 1)
+
+	// Reconfigure with a short promote delay (1 second).
+	resp, _ := tests.Put("http://localhost:7001/config", "application/json", bytes.NewBufferString(`{"activeSize":9, "promoteDelay":1}`))
+	if !assert.Equal(t, resp.StatusCode, 200) {
+		t.FailNow()
+	}
+
+	// Remove peer.
+	etcd := etcds[1]
+	etcds = append(etcds[:1], etcds[2:]...)
+	if err := etcd.Kill(); err != nil {
+		panic(err.Error())
+	}
+	etcd.Release()
+
+	// Wait for it to get dropped.
+	time.Sleep(server.PeerActivityMonitorTimeout + (1 * time.Second))
+
+	// Wait for the proxy to be promoted.
+	time.Sleep(server.ActiveMonitorTimeout + (1 * time.Second))
+
+	// Verify that we have 9 peers.
+	result, err = c.Get("_etcd/machines", true, true)
+	assert.NoError(t, err)
+	assert.Equal(t, len(result.Node.Nodes), 9)
+
+	// Verify that node10 is one of those peers.
+	result, err = c.Get("_etcd/machines/node10", false, false)
+	assert.NoError(t, err)
+
+	// Verify that there are no more proxies.
+	result, err = c.Get("_etcd/proxies", false, true)
+	assert.NoError(t, err)
+	if assert.Equal(t, len(result.Node.Nodes), 1) {
+		assert.Equal(t, result.Node.Nodes[0].Key, "/_etcd/proxies/node2")
+	}
+}