Method TestPickerUpdateOnDataCacheSizeDecrease

balancer/rls/balancer_test.go:682–895

Test that when a data cache entry is evicted due to config change in cache size, the picker is updated accordingly.

(t *testing.T)

// Test that when a data cache entry is evicted due to config change
// in cache size, the picker is updated accordingly.
func (s) TestPickerUpdateOnDataCacheSizeDecrease(t *testing.T) {
	// Override the clientConn update hook to get notified.
	clientConnUpdateDone := make(chan struct{}, 1)
	origClientConnUpdateHook := clientConnUpdateHook
	clientConnUpdateHook = func() { clientConnUpdateDone <- struct{}{} }
	defer func() { clientConnUpdateHook = origClientConnUpdateHook }()

	// Override the cache entry size func, and always return 1.
	origEntrySizeFunc := computeDataCacheEntrySize
	computeDataCacheEntrySize = func(cacheKey, *cacheEntry) int64 { return 1 }
	defer func() { computeDataCacheEntrySize = origEntrySizeFunc }()

	// Override the backoff strategy to return a large backoff which
	// will make sure the date cache entry remains in backoff for the
	// duration of the test.
	origBackoffStrategy := defaultBackoffStrategy
	defaultBackoffStrategy = &fakeBackoffStrategy{backoff: defaultTestTimeout}
	defer func() { defaultBackoffStrategy = origBackoffStrategy }()

	// Override the minEvictionDuration to ensure that when the config update
	// reduces the cache size, the resize operation is not stopped because
	// we find an entry whose minExpiryDuration has not elapsed.
	origMinEvictDuration := minEvictDuration
	minEvictDuration = time.Duration(0)
	defer func() { minEvictDuration = origMinEvictDuration }()

	// Register the top-level wrapping balancer which forwards calls to RLS.
	topLevelBalancerName := t.Name() + "top-level"
	var ccWrapper *stateCapturingCC
	stub.Register(topLevelBalancerName, stub.BalancerFuncs{
		Init: func(bd *stub.BalancerData) {
			ccWrapper = newStateCapturingCC(bd.ClientConn)
			bd.ChildBalancer = balancer.Get(Name).Build(ccWrapper, bd.BuildOptions)
		},
		ParseConfig: func(sc json.RawMessage) (serviceconfig.LoadBalancingConfig, error) {
			parser := balancer.Get(Name).(balancer.ConfigParser)
			return parser.ParseConfig(sc)
		},
		UpdateClientConnState: func(bd *stub.BalancerData, ccs balancer.ClientConnState) error {
			return bd.ChildBalancer.UpdateClientConnState(ccs)
		},
		Close: func(bd *stub.BalancerData) {
			bd.ChildBalancer.Close()
		},
	})

	// Start an RLS server and set the throttler to never throttle requests.
	rlsServer, rlsReqCh := rlstest.SetupFakeRLSServer(t, nil)
	overrideAdaptiveThrottler(t, neverThrottlingThrottler())

	// Register an LB policy to act as the child policy for RLS LB policy.
	childPolicyName := "test-child-policy" + t.Name()
	e2e.RegisterRLSChildPolicy(childPolicyName, nil)
	t.Logf("Registered child policy with name %q", childPolicyName)

	// Start a couple of test backends, and set up the fake RLS server to return
	// these as targets in the RLS response, based on request keys.
	// Start a couple of test backends, and set up the fake RLS server to return