Method TestConfigUpdate_DataCacheSizeDecrease

balancer/rls/balancer_test.go:563–659

TestConfigUpdate_DataCacheSizeDecrease tests the scenario where a config update decreases the data cache size. Verifies that entries are evicted from the cache.

(t *testing.T)

// update decreases the data cache size. Verifies that entries are evicted from
// the cache.
func (s) TestConfigUpdate_DataCacheSizeDecrease(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 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 }()

	// 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)

	// Build RLS service config with header matchers.
	rlsConfig := buildBasicRLSConfig(childPolicyName, rlsServer.Address)

	// 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.
	backendCh1, backendAddress1 := startBackend(t)
	backendCh2, backendAddress2 := startBackend(t)
	rlsServer.SetResponseCallback(func(_ context.Context, req *rlspb.RouteLookupRequest) *rlstest.RouteLookupResponse {
		if req.KeyMap["k1"] == "v1" {
			return &rlstest.RouteLookupResponse{Resp: &rlspb.RouteLookupResponse{Targets: []string{backendAddress1}}}
		}
		if req.KeyMap["k2"] == "v2" {
			return &rlstest.RouteLookupResponse{Resp: &rlspb.RouteLookupResponse{Targets: []string{backendAddress2}}}
		}
		return &rlstest.RouteLookupResponse{Err: errors.New("no keys in request metadata")}
	})

	// Register a manual resolver and push the RLS service config through it.
	r := startManualResolverWithConfig(t, rlsConfig)

	cc, err := grpc.NewClient(r.Scheme()+":///", grpc.WithResolvers(r), grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		t.Fatalf("grpc.NewClient() failed: %v", err)
	}
	defer cc.Close()
	cc.Connect()

	<-clientConnUpdateDone

	// Make an RPC and ensure it gets routed to the first backend.