open-consul/agent/proxycfg/testing.go

package proxycfg

import (
	"context"
	"fmt"
	"io/ioutil"
	"path"
	"path/filepath"
	"runtime"
	"sync"
	"sync/atomic"
	"time"

	"github.com/hashicorp/go-hclog"
	"github.com/mitchellh/go-testing-interface"
	"github.com/stretchr/testify/require"

	"github.com/hashicorp/consul/agent/cache"
	cachetype "github.com/hashicorp/consul/agent/cache-types"
	"github.com/hashicorp/consul/agent/connect"
	"github.com/hashicorp/consul/agent/structs"
	"github.com/hashicorp/consul/api"
)

// TestCacheTypes encapsulates all the different cache types proxycfg.State will
// watch/request for controlling one during testing.
type TestCacheTypes struct {
	roots             *ControllableCacheType
	leaf              *ControllableCacheType
	intentions        *ControllableCacheType
	health            *ControllableCacheType
	query             *ControllableCacheType
	compiledChain     *ControllableCacheType
	serviceHTTPChecks *ControllableCacheType
	configEntry       *ControllableCacheType
}

// NewTestCacheTypes creates a set of ControllableCacheTypes for all types that
// proxycfg will watch suitable for testing a proxycfg.State or Manager.
func NewTestCacheTypes(t testing.T) *TestCacheTypes {
	t.Helper()
	ct := &TestCacheTypes{
		roots:             NewControllableCacheType(t),
		leaf:              NewControllableCacheType(t),
		intentions:        NewControllableCacheType(t),
		health:            NewControllableCacheType(t),
		query:             NewControllableCacheType(t),
		compiledChain:     NewControllableCacheType(t),
		serviceHTTPChecks: NewControllableCacheType(t),
		configEntry:       NewControllableCacheType(t),
	}
	ct.query.blocking = false
	return ct
}

// TestCacheWithTypes registers ControllableCacheTypes for all types that
// proxycfg will watch suitable for testing a proxycfg.State or Manager.
func TestCacheWithTypes(t testing.T, types *TestCacheTypes) *cache.Cache {
	c := cache.New(cache.Options{})
	c.RegisterType(cachetype.ConnectCARootName, types.roots)
	c.RegisterType(cachetype.ConnectCALeafName, types.leaf)
	c.RegisterType(cachetype.IntentionMatchName, types.intentions)
	c.RegisterType(cachetype.HealthServicesName, types.health)
	c.RegisterType(cachetype.PreparedQueryName, types.query)
	c.RegisterType(cachetype.CompiledDiscoveryChainName, types.compiledChain)
	c.RegisterType(cachetype.ServiceHTTPChecksName, types.serviceHTTPChecks)
	c.RegisterType(cachetype.ConfigEntryName, types.configEntry)

	return c
}

// TestCerts generates a CA and Leaf suitable for returning as mock CA
// root/leaf cache requests.
func TestCerts(t testing.T) (*structs.IndexedCARoots, *structs.IssuedCert) {
	t.Helper()

	ca := connect.TestCA(t, nil)
	roots := &structs.IndexedCARoots{
		ActiveRootID: ca.ID,
		TrustDomain:  fmt.Sprintf("%s.consul", connect.TestClusterID),
		Roots:        []*structs.CARoot{ca},
	}
	return roots, TestLeafForCA(t, ca)
}

// TestLeafForCA generates new Leaf suitable for returning as mock CA
// leaf cache response, signed by an existing CA.
func TestLeafForCA(t testing.T, ca *structs.CARoot) *structs.IssuedCert {
	leafPEM, pkPEM := connect.TestLeaf(t, "web", ca)

	leafCert, err := connect.ParseCert(leafPEM)
	require.NoError(t, err)

	return &structs.IssuedCert{
		SerialNumber:  connect.EncodeSerialNumber(leafCert.SerialNumber),
		CertPEM:       leafPEM,
		PrivateKeyPEM: pkPEM,
		Service:       "web",
		ServiceURI:    leafCert.URIs[0].String(),
		ValidAfter:    leafCert.NotBefore,
		ValidBefore:   leafCert.NotAfter,
	}
}

// TestIntentions returns a sample intentions match result useful to
// mocking service discovery cache results.
func TestIntentions() *structs.IndexedIntentionMatches {
	return &structs.IndexedIntentionMatches{
		Matches: []structs.Intentions{
			[]*structs.Intention{
				{
					ID:              "foo",
					SourceNS:        "default",
					SourceName:      "billing",
					DestinationNS:   "default",
					DestinationName: "web",
					Action:          structs.IntentionActionAllow,
				},
			},
		},
	}
}

// TestUpstreamNodes returns a sample service discovery result useful to
// mocking service discovery cache results.
func TestUpstreamNodes(t testing.T, service string) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test1",
				Node:       "test1",
				Address:    "10.10.1.1",
				Datacenter: "dc1",
				Partition:  structs.NodeEnterpriseMetaInDefaultPartition().PartitionOrEmpty(),
			},
			Service: structs.TestNodeServiceWithName(t, service),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test2",
				Node:       "test2",
				Address:    "10.10.1.2",
				Datacenter: "dc1",
				Partition:  structs.NodeEnterpriseMetaInDefaultPartition().PartitionOrEmpty(),
			},
			Service: structs.TestNodeServiceWithName(t, service),
		},
	}
}

// TestPreparedQueryNodes returns instances of a service spread across two datacenters.
// The service instance names use a "-target" suffix to ensure we don't use the
// prepared query's name for SAN validation.
// The name of prepared queries won't always match the name of the service they target.
func TestPreparedQueryNodes(t testing.T, query string) structs.CheckServiceNodes {
	nodes := structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test1",
				Node:       "test1",
				Address:    "10.10.1.1",
				Datacenter: "dc1",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindConnectProxy,
				Service: query + "-sidecar-proxy",
				Port:    8080,
				Proxy: structs.ConnectProxyConfig{
					DestinationServiceName: query + "-target",
				},
			},
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test2",
				Node:       "test2",
				Address:    "10.20.1.2",
				Datacenter: "dc2",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindTypical,
				Service: query + "-target",
				Port:    8080,
				Connect: structs.ServiceConnect{Native: true},
			},
		},
	}
	return nodes
}

func TestUpstreamNodesInStatus(t testing.T, status string) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test1",
				Node:       "test1",
				Address:    "10.10.1.1",
				Datacenter: "dc1",
			},
			Service: structs.TestNodeService(t),
			Checks: structs.HealthChecks{
				&structs.HealthCheck{
					Node:        "test1",
					ServiceName: "web",
					Name:        "force",
					Status:      status,
				},
			},
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test2",
				Node:       "test2",
				Address:    "10.10.1.2",
				Datacenter: "dc1",
			},
			Service: structs.TestNodeService(t),
			Checks: structs.HealthChecks{
				&structs.HealthCheck{
					Node:        "test2",
					ServiceName: "web",
					Name:        "force",
					Status:      status,
				},
			},
		},
	}
}

func TestUpstreamNodesDC2(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test1",
				Node:       "test1",
				Address:    "10.20.1.1",
				Datacenter: "dc2",
			},
			Service: structs.TestNodeService(t),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test2",
				Node:       "test2",
				Address:    "10.20.1.2",
				Datacenter: "dc2",
			},
			Service: structs.TestNodeService(t),
		},
	}
}

func TestUpstreamNodesInStatusDC2(t testing.T, status string) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test1",
				Node:       "test1",
				Address:    "10.20.1.1",
				Datacenter: "dc2",
			},
			Service: structs.TestNodeService(t),
			Checks: structs.HealthChecks{
				&structs.HealthCheck{
					Node:        "test1",
					ServiceName: "web",
					Name:        "force",
					Status:      status,
				},
			},
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "test2",
				Node:       "test2",
				Address:    "10.20.1.2",
				Datacenter: "dc2",
			},
			Service: structs.TestNodeService(t),
			Checks: structs.HealthChecks{
				&structs.HealthCheck{
					Node:        "test2",
					ServiceName: "web",
					Name:        "force",
					Status:      status,
				},
			},
		},
	}
}

func TestUpstreamNodesAlternate(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "alt-test1",
				Node:       "alt-test1",
				Address:    "10.20.1.1",
				Datacenter: "dc1",
			},
			Service: structs.TestNodeService(t),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "alt-test2",
				Node:       "alt-test2",
				Address:    "10.20.1.2",
				Datacenter: "dc1",
			},
			Service: structs.TestNodeService(t),
		},
	}
}

func TestGatewayNodesDC1(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-1",
				Node:       "mesh-gateway",
				Address:    "10.10.1.1",
				Datacenter: "dc1",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.10.1.1", 8443,
				structs.ServiceAddress{Address: "10.10.1.1", Port: 8443},
				structs.ServiceAddress{Address: "198.118.1.1", Port: 443}),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-2",
				Node:       "mesh-gateway",
				Address:    "10.10.1.2",
				Datacenter: "dc1",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.10.1.2", 8443,
				structs.ServiceAddress{Address: "10.0.1.2", Port: 8443},
				structs.ServiceAddress{Address: "198.118.1.2", Port: 443}),
		},
	}
}

func TestGatewayNodesDC2(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-1",
				Node:       "mesh-gateway",
				Address:    "10.0.1.1",
				Datacenter: "dc2",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.0.1.1", 8443,
				structs.ServiceAddress{Address: "10.0.1.1", Port: 8443},
				structs.ServiceAddress{Address: "198.18.1.1", Port: 443}),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-2",
				Node:       "mesh-gateway",
				Address:    "10.0.1.2",
				Datacenter: "dc2",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.0.1.2", 8443,
				structs.ServiceAddress{Address: "10.0.1.2", Port: 8443},
				structs.ServiceAddress{Address: "198.18.1.2", Port: 443}),
		},
	}
}

func TestGatewayNodesDC3(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-1",
				Node:       "mesh-gateway",
				Address:    "10.30.1.1",
				Datacenter: "dc3",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.1", 8443,
				structs.ServiceAddress{Address: "10.0.1.1", Port: 8443},
				structs.ServiceAddress{Address: "198.38.1.1", Port: 443}),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-2",
				Node:       "mesh-gateway",
				Address:    "10.30.1.2",
				Datacenter: "dc3",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.2", 8443,
				structs.ServiceAddress{Address: "10.30.1.2", Port: 8443},
				structs.ServiceAddress{Address: "198.38.1.2", Port: 443}),
		},
	}
}

func TestGatewayNodesDC4Hostname(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-1",
				Node:       "mesh-gateway",
				Address:    "10.30.1.1",
				Datacenter: "dc4",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.1", 8443,
				structs.ServiceAddress{Address: "10.0.1.1", Port: 8443},
				structs.ServiceAddress{Address: "123.us-west-2.elb.notaws.com", Port: 443}),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-2",
				Node:       "mesh-gateway",
				Address:    "10.30.1.2",
				Datacenter: "dc4",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.2", 8443,
				structs.ServiceAddress{Address: "10.30.1.2", Port: 8443},
				structs.ServiceAddress{Address: "456.us-west-2.elb.notaws.com", Port: 443}),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-3",
				Node:       "mesh-gateway",
				Address:    "10.30.1.3",
				Datacenter: "dc4",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.3", 8443,
				structs.ServiceAddress{Address: "10.30.1.3", Port: 8443},
				structs.ServiceAddress{Address: "198.38.1.1", Port: 443}),
		},
	}
}

func TestGatewayNodesDC5Hostname(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-1",
				Node:       "mesh-gateway",
				Address:    "10.30.1.1",
				Datacenter: "dc5",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.1", 8443,
				structs.ServiceAddress{Address: "10.0.1.1", Port: 8443},
				structs.ServiceAddress{Address: "123.us-west-2.elb.notaws.com", Port: 443}),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-2",
				Node:       "mesh-gateway",
				Address:    "10.30.1.2",
				Datacenter: "dc5",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.2", 8443,
				structs.ServiceAddress{Address: "10.30.1.2", Port: 8443},
				structs.ServiceAddress{Address: "456.us-west-2.elb.notaws.com", Port: 443}),
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-3",
				Node:       "mesh-gateway",
				Address:    "10.30.1.3",
				Datacenter: "dc5",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.3", 8443,
				structs.ServiceAddress{Address: "10.30.1.3", Port: 8443},
				structs.ServiceAddress{Address: "198.38.1.1", Port: 443}),
		},
	}
}

func TestGatewayNodesDC6Hostname(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "mesh-gateway-1",
				Node:       "mesh-gateway",
				Address:    "10.30.1.1",
				Datacenter: "dc6",
			},
			Service: structs.TestNodeServiceMeshGatewayWithAddrs(t,
				"10.30.1.1", 8443,
				structs.ServiceAddress{Address: "10.0.1.1", Port: 8443},
				structs.ServiceAddress{Address: "123.us-east-1.elb.notaws.com", Port: 443}),
			Checks: structs.HealthChecks{
				{
					Status: api.HealthCritical,
				},
			},
		},
	}
}

func TestGatewayServiceGroupBarDC1(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "bar-node-1",
				Node:       "bar-node-1",
				Address:    "10.1.1.4",
				Datacenter: "dc1",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindConnectProxy,
				Service: "bar-sidecar-proxy",
				Address: "172.16.1.6",
				Port:    2222,
				Meta: map[string]string{
					"version": "1",
				},
				Proxy: structs.ConnectProxyConfig{
					DestinationServiceName: "bar",
					Upstreams:              structs.TestUpstreams(t),
				},
			},
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "bar-node-2",
				Node:       "bar-node-2",
				Address:    "10.1.1.5",
				Datacenter: "dc1",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindConnectProxy,
				Service: "bar-sidecar-proxy",
				Address: "172.16.1.7",
				Port:    2222,
				Meta: map[string]string{
					"version": "1",
				},
				Proxy: structs.ConnectProxyConfig{
					DestinationServiceName: "bar",
					Upstreams:              structs.TestUpstreams(t),
				},
			},
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "bar-node-3",
				Node:       "bar-node-3",
				Address:    "10.1.1.6",
				Datacenter: "dc1",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindConnectProxy,
				Service: "bar-sidecar-proxy",
				Address: "172.16.1.8",
				Port:    2222,
				Meta: map[string]string{
					"version": "2",
				},
				Proxy: structs.ConnectProxyConfig{
					DestinationServiceName: "bar",
					Upstreams:              structs.TestUpstreams(t),
				},
			},
		},
	}
}

func TestGatewayServiceGroupFooDC1(t testing.T) structs.CheckServiceNodes {
	return structs.CheckServiceNodes{
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "foo-node-1",
				Node:       "foo-node-1",
				Address:    "10.1.1.1",
				Datacenter: "dc1",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindConnectProxy,
				Service: "foo-sidecar-proxy",
				Address: "172.16.1.3",
				Port:    2222,
				Meta: map[string]string{
					"version": "1",
				},
				Proxy: structs.ConnectProxyConfig{
					DestinationServiceName: "foo",
					Upstreams:              structs.TestUpstreams(t),
				},
			},
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "foo-node-2",
				Node:       "foo-node-2",
				Address:    "10.1.1.2",
				Datacenter: "dc1",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindConnectProxy,
				Service: "foo-sidecar-proxy",
				Address: "172.16.1.4",
				Port:    2222,
				Meta: map[string]string{
					"version": "1",
				},
				Proxy: structs.ConnectProxyConfig{
					DestinationServiceName: "foo",
					Upstreams:              structs.TestUpstreams(t),
				},
			},
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "foo-node-3",
				Node:       "foo-node-3",
				Address:    "10.1.1.3",
				Datacenter: "dc1",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindConnectProxy,
				Service: "foo-sidecar-proxy",
				Address: "172.16.1.5",
				Port:    2222,
				Meta: map[string]string{
					"version": "2",
				},
				Proxy: structs.ConnectProxyConfig{
					DestinationServiceName: "foo",
					Upstreams:              structs.TestUpstreams(t),
				},
			},
		},
		structs.CheckServiceNode{
			Node: &structs.Node{
				ID:         "foo-node-4",
				Node:       "foo-node-4",
				Address:    "10.1.1.7",
				Datacenter: "dc1",
			},
			Service: &structs.NodeService{
				Kind:    structs.ServiceKindConnectProxy,
				Service: "foo-sidecar-proxy",
				Address: "172.16.1.9",
				Port:    2222,
				Meta: map[string]string{
					"version": "2",
				},
				Proxy: structs.ConnectProxyConfig{
					DestinationServiceName: "foo",
					Upstreams:              structs.TestUpstreams(t),
				},
			},
			Checks: structs.HealthChecks{
				&structs.HealthCheck{
					Node:        "foo-node-4",
					ServiceName: "foo-sidecar-proxy",
					Name:        "proxy-alive",
					Status:      "warning",
				},
			},
		},
	}
}

type noopCacheNotifier struct{}

var _ CacheNotifier = (*noopCacheNotifier)(nil)

func (*noopCacheNotifier) Notify(_ context.Context, _ string, _ cache.Request, _ string, _ chan<- UpdateEvent) error {
	return nil
}

type noopHealth struct{}

var _ Health = (*noopHealth)(nil)

func (*noopHealth) Notify(_ context.Context, _ structs.ServiceSpecificRequest, _ string, _ chan<- UpdateEvent) error {
	return nil
}

// testConfigSnapshotFixture helps you execute normal proxycfg event machinery
// to assemble a ConfigSnapshot via standard means to ensure test data used in
// any tests is actually a valid configuration.
//
// The provided ns argument will be manipulated by the nsFn callback if present
// before it is used.
//
// The events provided in the updates slice will be fed into the event
// machinery.
func testConfigSnapshotFixture(
	t testing.T,
	ns *structs.NodeService,
	nsFn func(ns *structs.NodeService),
	serverSNIFn ServerSNIFunc,
	updates []UpdateEvent,
) *ConfigSnapshot {
	const token = ""

	if nsFn != nil {
		nsFn(ns)
	}

	config := stateConfig{
		logger: hclog.NewNullLogger(),
		source: &structs.QuerySource{
			Datacenter: "dc1",
		},
		cache:  &noopCacheNotifier{},
		health: &noopHealth{},
		dnsConfig: DNSConfig{ // TODO: make configurable
			Domain:    "consul",
			AltDomain: "",
		},
		serverSNIFn:           serverSNIFn,
		intentionDefaultAllow: false, // TODO: make configurable
	}
	s, err := newServiceInstanceFromNodeService(ns, token)
	if err != nil {
		t.Fatalf("err: %v", err)
		return nil
	}

	handler, err := newKindHandler(config, s, nil) // NOTE: nil channel
	if err != nil {
		t.Fatalf("err: %v", err)
		return nil
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	snap, err := handler.initialize(ctx)
	if err != nil {
		t.Fatalf("err: %v", err)
		return nil
	}

	for _, u := range updates {
		if err := handler.handleUpdate(ctx, u, &snap); err != nil {
			t.Fatalf("Failed to handle update from watch %q: %v", u.CorrelationID, err)
			return nil
		}
	}
	return &snap
}

func testSpliceEvents(base, extra []UpdateEvent) []UpdateEvent {
	if len(extra) == 0 {
		return base
	}
	var (
		hasExtra      = make(map[string]UpdateEvent)
		completeExtra = make(map[string]struct{})

		allEvents []UpdateEvent
	)

	for _, e := range extra {
		hasExtra[e.CorrelationID] = e
	}

	// Override base events with extras if they share the same correlationID,
	// then put the rest of the extras at the end.
	for _, e := range base {
		if extraEvt, ok := hasExtra[e.CorrelationID]; ok {
			if extraEvt.Result != nil { // nil results are tombstones
				allEvents = append(allEvents, extraEvt)
			}
			completeExtra[e.CorrelationID] = struct{}{}
		} else {
			allEvents = append(allEvents, e)
		}
	}
	for _, e := range extra {
		if _, ok := completeExtra[e.CorrelationID]; !ok {
			allEvents = append(allEvents, e)
		}
	}
	return allEvents
}

func testSpliceNodeServiceFunc(prev, next func(ns *structs.NodeService)) func(ns *structs.NodeService) {
	return func(ns *structs.NodeService) {
		if prev != nil {
			prev(ns)
		}
		next(ns)
	}
}

// ControllableCacheType is a cache.Type that simulates a typical blocking RPC
// but lets us control the responses and when they are delivered easily.
type ControllableCacheType struct {
	index uint64
	value sync.Map
	// Need a condvar to trigger all blocking requests (there might be multiple
	// for same type due to background refresh and timing issues) when values
	// change. Chans make it nondeterministic which one triggers or need extra
	// locking to coordinate replacing after close etc.
	triggerMu sync.Mutex
	trigger   *sync.Cond
	blocking  bool
	lastReq   atomic.Value
}

// NewControllableCacheType returns a cache.Type that can be controlled for
// testing.
func NewControllableCacheType(t testing.T) *ControllableCacheType {
	c := &ControllableCacheType{
		index:    5,
		blocking: true,
	}
	c.trigger = sync.NewCond(&c.triggerMu)
	return c
}

// Set sets the response value to be returned from subsequent cache gets for the
// type.
func (ct *ControllableCacheType) Set(key string, value interface{}) {
	atomic.AddUint64(&ct.index, 1)
	ct.value.Store(key, value)
	ct.triggerMu.Lock()
	ct.trigger.Broadcast()
	ct.triggerMu.Unlock()
}

// Fetch implements cache.Type. It simulates blocking or non-blocking queries.
func (ct *ControllableCacheType) Fetch(opts cache.FetchOptions, req cache.Request) (cache.FetchResult, error) {
	index := atomic.LoadUint64(&ct.index)

	ct.lastReq.Store(req)

	shouldBlock := ct.blocking && opts.MinIndex > 0 && opts.MinIndex == index
	if shouldBlock {
		// Wait for return to be triggered. We ignore timeouts based on opts.Timeout
		// since in practice they will always be way longer than our tests run for
		// and the caller can simulate timeout by triggering return without changing
		// index or value.
		ct.triggerMu.Lock()
		ct.trigger.Wait()
		ct.triggerMu.Unlock()
	}

	info := req.CacheInfo()
	key := path.Join(info.Key, info.Datacenter) // omit token for testing purposes

	// reload index as it probably got bumped
	index = atomic.LoadUint64(&ct.index)
	val, _ := ct.value.Load(key)

	if err, ok := val.(error); ok {
		return cache.FetchResult{
			Value: nil,
			Index: index,
		}, err
	}
	return cache.FetchResult{
		Value: val,
		Index: index,
	}, nil
}

func (ct *ControllableCacheType) RegisterOptions() cache.RegisterOptions {
	return cache.RegisterOptions{
		Refresh:          ct.blocking,
		SupportsBlocking: ct.blocking,
		QueryTimeout:     10 * time.Minute,
	}
}

// golden is used to read golden files stores in consul/agent/xds/testdata
func golden(t testing.T, name string) string {
	t.Helper()

	golden := filepath.Join(projectRoot(), "../", "/xds/testdata", name+".golden")
	expected, err := ioutil.ReadFile(golden)
	require.NoError(t, err)

	return string(expected)
}

func projectRoot() string {
	_, base, _, _ := runtime.Caller(0)
	return filepath.Dir(base)
}