consul/agent/proxycfg/manager_test.go
R.B. Boyer 424f3cdd2c
proxycfg: introduce explicit UpstreamID in lieu of bare string (#12125)
The gist here is that now we use a value-type struct proxycfg.UpstreamID
as the map key in ConfigSnapshot maps where we used to use "upstream
id-ish" strings. These are internal only and used just for bidirectional
trips through the agent cache keyspace (like the discovery chain target
struct).

For the few places where the upstream id needs to be projected into xDS,
that's what (proxycfg.UpstreamID).EnvoyID() is for. This lets us ALWAYS
inject the partition and namespace into these things without making
stuff like the golden testdata diverge.
2022-01-20 10:12:04 -06:00

745 lines
22 KiB
Go

package proxycfg
import (
"context"
"path"
"testing"
"time"
"github.com/mitchellh/copystructure"
"github.com/stretchr/testify/require"
"golang.org/x/time/rate"
"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/consul/discoverychain"
"github.com/hashicorp/consul/agent/local"
"github.com/hashicorp/consul/agent/rpcclient/health"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/agent/token"
"github.com/hashicorp/consul/api"
"github.com/hashicorp/consul/sdk/testutil"
)
func mustCopyProxyConfig(t *testing.T, ns *structs.NodeService) structs.ConnectProxyConfig {
cfg, err := copyProxyConfig(ns)
require.NoError(t, err)
return cfg
}
// assertLastReqArgs verifies that each request type had the correct source
// parameters (e.g. Datacenter name) and token.
func assertLastReqArgs(t *testing.T, types *TestCacheTypes, token string, source *structs.QuerySource) {
t.Helper()
// Roots needs correct DC and token
rootReq := types.roots.lastReq.Load()
require.IsType(t, rootReq, &structs.DCSpecificRequest{})
require.Equal(t, token, rootReq.(*structs.DCSpecificRequest).Token)
require.Equal(t, source.Datacenter, rootReq.(*structs.DCSpecificRequest).Datacenter)
// Leaf needs correct DC and token
leafReq := types.leaf.lastReq.Load()
require.IsType(t, leafReq, &cachetype.ConnectCALeafRequest{})
require.Equal(t, token, leafReq.(*cachetype.ConnectCALeafRequest).Token)
require.Equal(t, source.Datacenter, leafReq.(*cachetype.ConnectCALeafRequest).Datacenter)
// Intentions needs correct DC and token
intReq := types.intentions.lastReq.Load()
require.IsType(t, intReq, &structs.IntentionQueryRequest{})
require.Equal(t, token, intReq.(*structs.IntentionQueryRequest).Token)
require.Equal(t, source.Datacenter, intReq.(*structs.IntentionQueryRequest).Datacenter)
}
func TestManager_BasicLifecycle(t *testing.T) {
if testing.Short() {
t.Skip("too slow for testing.Short")
}
// Create a bunch of common data for the various test cases.
roots, leaf := TestCerts(t)
dbDefaultChain := func() *structs.CompiledDiscoveryChain {
return discoverychain.TestCompileConfigEntries(t, "db", "default", "default", "dc1", connect.TestClusterID+".consul", func(req *discoverychain.CompileRequest) {
// This is because structs.TestUpstreams uses an opaque config
// to override connect timeouts.
req.OverrideConnectTimeout = 1 * time.Second
}, &structs.ServiceResolverConfigEntry{
Kind: structs.ServiceResolver,
Name: "db",
})
}
dbSplitChain := func() *structs.CompiledDiscoveryChain {
return discoverychain.TestCompileConfigEntries(t, "db", "default", "default", "dc1", "trustdomain.consul", func(req *discoverychain.CompileRequest) {
// This is because structs.TestUpstreams uses an opaque config
// to override connect timeouts.
req.OverrideConnectTimeout = 1 * time.Second
}, &structs.ProxyConfigEntry{
Kind: structs.ProxyDefaults,
Name: structs.ProxyConfigGlobal,
Config: map[string]interface{}{
"protocol": "http",
},
}, &structs.ServiceResolverConfigEntry{
Kind: structs.ServiceResolver,
Name: "db",
Subsets: map[string]structs.ServiceResolverSubset{
"v1": {
Filter: "Service.Meta.version == v1",
},
"v2": {
Filter: "Service.Meta.version == v2",
},
},
}, &structs.ServiceSplitterConfigEntry{
Kind: structs.ServiceSplitter,
Name: "db",
Splits: []structs.ServiceSplit{
{Weight: 60, ServiceSubset: "v1"},
{Weight: 40, ServiceSubset: "v2"},
},
})
}
upstreams := structs.TestUpstreams(t)
for i := range upstreams {
upstreams[i].DestinationNamespace = structs.IntentionDefaultNamespace
upstreams[i].DestinationPartition = api.PartitionDefaultName
}
webProxy := &structs.NodeService{
Kind: structs.ServiceKindConnectProxy,
ID: "web-sidecar-proxy",
Service: "web-sidecar-proxy",
Port: 9999,
Meta: map[string]string{},
Proxy: structs.ConnectProxyConfig{
DestinationServiceID: "web",
DestinationServiceName: "web",
LocalServiceAddress: "127.0.0.1",
LocalServicePort: 8080,
Config: map[string]interface{}{
"foo": "bar",
},
Upstreams: upstreams,
},
}
rootsCacheKey := testGenCacheKey(&structs.DCSpecificRequest{
Datacenter: "dc1",
QueryOptions: structs.QueryOptions{Token: "my-token"},
})
leafCacheKey := testGenCacheKey(&cachetype.ConnectCALeafRequest{
Datacenter: "dc1",
Token: "my-token",
Service: "web",
})
intentionCacheKey := testGenCacheKey(&structs.IntentionQueryRequest{
Datacenter: "dc1",
QueryOptions: structs.QueryOptions{Token: "my-token"},
Match: &structs.IntentionQueryMatch{
Type: structs.IntentionMatchDestination,
Entries: []structs.IntentionMatchEntry{
{
Namespace: structs.IntentionDefaultNamespace,
Partition: structs.IntentionDefaultNamespace,
Name: "web",
},
},
},
})
dbChainCacheKey := testGenCacheKey(&structs.DiscoveryChainRequest{
Name: "db",
EvaluateInDatacenter: "dc1",
EvaluateInNamespace: "default",
EvaluateInPartition: "default",
// This is because structs.TestUpstreams uses an opaque config
// to override connect timeouts.
OverrideConnectTimeout: 1 * time.Second,
Datacenter: "dc1",
QueryOptions: structs.QueryOptions{Token: "my-token"},
})
dbHealthCacheKey := testGenCacheKey(&structs.ServiceSpecificRequest{
Datacenter: "dc1",
QueryOptions: structs.QueryOptions{Token: "my-token", Filter: ""},
ServiceName: "db",
Connect: true,
EnterpriseMeta: *structs.DefaultEnterpriseMetaInDefaultPartition(),
})
db_v1_HealthCacheKey := testGenCacheKey(&structs.ServiceSpecificRequest{
Datacenter: "dc1",
QueryOptions: structs.QueryOptions{Token: "my-token",
Filter: "Service.Meta.version == v1",
},
ServiceName: "db",
Connect: true,
EnterpriseMeta: *structs.DefaultEnterpriseMetaInDefaultPartition(),
})
db_v2_HealthCacheKey := testGenCacheKey(&structs.ServiceSpecificRequest{
Datacenter: "dc1",
QueryOptions: structs.QueryOptions{Token: "my-token",
Filter: "Service.Meta.version == v2",
},
ServiceName: "db",
Connect: true,
EnterpriseMeta: *structs.DefaultEnterpriseMetaInDefaultPartition(),
})
db := structs.NewServiceName("db", nil)
dbUID := NewUpstreamIDFromServiceName(db)
// Create test cases using some of the common data above.
tests := []*testcase_BasicLifecycle{
{
name: "simple-default-resolver",
setup: func(t *testing.T, types *TestCacheTypes) {
// Note that we deliberately leave the 'geo-cache' prepared query to time out
types.health.Set(dbHealthCacheKey, &structs.IndexedCheckServiceNodes{
Nodes: TestUpstreamNodes(t, db.Name),
})
types.compiledChain.Set(dbChainCacheKey, &structs.DiscoveryChainResponse{
Chain: dbDefaultChain(),
})
},
expectSnap: &ConfigSnapshot{
Kind: structs.ServiceKindConnectProxy,
Service: webProxy.Service,
ProxyID: webProxy.CompoundServiceID(),
Address: webProxy.Address,
Port: webProxy.Port,
Proxy: mustCopyProxyConfig(t, webProxy),
ServiceMeta: webProxy.Meta,
TaggedAddresses: make(map[string]structs.ServiceAddress),
Roots: roots,
ConnectProxy: configSnapshotConnectProxy{
ConfigSnapshotUpstreams: ConfigSnapshotUpstreams{
Leaf: leaf,
DiscoveryChain: map[UpstreamID]*structs.CompiledDiscoveryChain{
dbUID: dbDefaultChain(),
},
WatchedDiscoveryChains: map[UpstreamID]context.CancelFunc{},
WatchedUpstreams: nil, // Clone() clears this out
WatchedUpstreamEndpoints: map[UpstreamID]map[string]structs.CheckServiceNodes{
dbUID: {
"db.default.default.dc1": TestUpstreamNodes(t, db.Name),
},
},
WatchedGateways: nil, // Clone() clears this out
WatchedGatewayEndpoints: map[UpstreamID]map[string]structs.CheckServiceNodes{
dbUID: {},
},
UpstreamConfig: map[UpstreamID]*structs.Upstream{
NewUpstreamID(&upstreams[0]): &upstreams[0],
NewUpstreamID(&upstreams[1]): &upstreams[1],
NewUpstreamID(&upstreams[2]): &upstreams[2],
},
PassthroughUpstreams: map[UpstreamID]ServicePassthroughAddrs{},
},
PreparedQueryEndpoints: map[UpstreamID]structs.CheckServiceNodes{},
WatchedServiceChecks: map[structs.ServiceID][]structs.CheckType{},
Intentions: TestIntentions().Matches[0],
IntentionsSet: true,
},
Datacenter: "dc1",
Locality: GatewayKey{Datacenter: "dc1", Partition: structs.PartitionOrDefault("")},
},
},
{
name: "chain-resolver-with-version-split",
setup: func(t *testing.T, types *TestCacheTypes) {
// Note that we deliberately leave the 'geo-cache' prepared query to time out
types.health.Set(db_v1_HealthCacheKey, &structs.IndexedCheckServiceNodes{
Nodes: TestUpstreamNodes(t, db.Name),
})
types.health.Set(db_v2_HealthCacheKey, &structs.IndexedCheckServiceNodes{
Nodes: TestUpstreamNodesAlternate(t),
})
types.compiledChain.Set(dbChainCacheKey, &structs.DiscoveryChainResponse{
Chain: dbSplitChain(),
})
},
expectSnap: &ConfigSnapshot{
Kind: structs.ServiceKindConnectProxy,
Service: webProxy.Service,
ProxyID: webProxy.CompoundServiceID(),
Address: webProxy.Address,
Port: webProxy.Port,
Proxy: mustCopyProxyConfig(t, webProxy),
ServiceMeta: webProxy.Meta,
TaggedAddresses: make(map[string]structs.ServiceAddress),
Roots: roots,
ConnectProxy: configSnapshotConnectProxy{
ConfigSnapshotUpstreams: ConfigSnapshotUpstreams{
Leaf: leaf,
DiscoveryChain: map[UpstreamID]*structs.CompiledDiscoveryChain{
dbUID: dbSplitChain(),
},
WatchedDiscoveryChains: map[UpstreamID]context.CancelFunc{},
WatchedUpstreams: nil, // Clone() clears this out
WatchedUpstreamEndpoints: map[UpstreamID]map[string]structs.CheckServiceNodes{
dbUID: {
"v1.db.default.default.dc1": TestUpstreamNodes(t, db.Name),
"v2.db.default.default.dc1": TestUpstreamNodesAlternate(t),
},
},
WatchedGateways: nil, // Clone() clears this out
WatchedGatewayEndpoints: map[UpstreamID]map[string]structs.CheckServiceNodes{
dbUID: {},
},
UpstreamConfig: map[UpstreamID]*structs.Upstream{
NewUpstreamID(&upstreams[0]): &upstreams[0],
NewUpstreamID(&upstreams[1]): &upstreams[1],
NewUpstreamID(&upstreams[2]): &upstreams[2],
},
PassthroughUpstreams: map[UpstreamID]ServicePassthroughAddrs{},
},
PreparedQueryEndpoints: map[UpstreamID]structs.CheckServiceNodes{},
WatchedServiceChecks: map[structs.ServiceID][]structs.CheckType{},
Intentions: TestIntentions().Matches[0],
IntentionsSet: true,
},
Datacenter: "dc1",
Locality: GatewayKey{Datacenter: "dc1", Partition: structs.PartitionOrDefault("")},
},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
require.NotNil(t, tt.setup)
require.NotNil(t, tt.expectSnap)
// Use a mocked cache to make life simpler
types := NewTestCacheTypes(t)
// Setup initial values
types.roots.Set(rootsCacheKey, roots)
types.leaf.Set(leafCacheKey, leaf)
types.intentions.Set(intentionCacheKey, TestIntentions())
tt.setup(t, types)
expectSnapCopy, err := copystructure.Copy(tt.expectSnap)
require.NoError(t, err)
webProxyCopy, err := copystructure.Copy(webProxy)
require.NoError(t, err)
testManager_BasicLifecycle(t, types,
rootsCacheKey, leafCacheKey,
roots,
webProxyCopy.(*structs.NodeService),
local.Config{},
expectSnapCopy.(*ConfigSnapshot),
)
})
}
}
type testcase_BasicLifecycle struct {
name string
setup func(t *testing.T, types *TestCacheTypes)
webProxy *structs.NodeService
expectSnap *ConfigSnapshot
}
func testManager_BasicLifecycle(
t *testing.T,
types *TestCacheTypes,
rootsCacheKey, leafCacheKey string,
roots *structs.IndexedCARoots,
webProxy *structs.NodeService,
agentConfig local.Config,
expectSnap *ConfigSnapshot,
) {
c := TestCacheWithTypes(t, types)
require := require.New(t)
logger := testutil.Logger(t)
state := local.NewState(agentConfig, logger, &token.Store{})
source := &structs.QuerySource{Datacenter: "dc1"}
// Stub state syncing
state.TriggerSyncChanges = func() {}
// Create manager
m, err := NewManager(ManagerConfig{
Cache: c,
Health: &health.Client{Cache: c, CacheName: cachetype.HealthServicesName},
State: state,
Source: source,
Logger: logger,
})
require.NoError(err)
// And run it
go func() {
err := m.Run()
require.NoError(err)
}()
// BEFORE we register, we should be able to get a watch channel
wCh, cancel := m.Watch(webProxy.CompoundServiceID())
defer cancel()
// And it should block with nothing sent on it yet
assertWatchChanBlocks(t, wCh)
require.NoError(state.AddService(webProxy, "my-token"))
// We should see the initial config delivered but not until after the
// coalesce timeout
start := time.Now()
assertWatchChanRecvs(t, wCh, expectSnap)
require.True(time.Since(start) >= coalesceTimeout)
assertLastReqArgs(t, types, "my-token", source)
// Update NodeConfig
webProxy.Port = 7777
require.NoError(state.AddService(webProxy, "my-token"))
expectSnap.Port = 7777
assertWatchChanRecvs(t, wCh, expectSnap)
// Register a second watcher
wCh2, cancel2 := m.Watch(webProxy.CompoundServiceID())
defer cancel2()
// New watcher should immediately receive the current state
assertWatchChanRecvs(t, wCh2, expectSnap)
// Change token
require.NoError(state.AddService(webProxy, "other-token"))
assertWatchChanRecvs(t, wCh, expectSnap)
assertWatchChanRecvs(t, wCh2, expectSnap)
// This is actually sort of timing dependent - the cache background fetcher
// will still be fetching with the old token, but we rely on the fact that our
// mock type will have been blocked on those for a while.
assertLastReqArgs(t, types, "other-token", source)
// Update roots
newRoots, newLeaf := TestCerts(t)
newRoots.Roots = append(newRoots.Roots, roots.Roots...)
types.roots.Set(rootsCacheKey, newRoots)
// Expect new roots in snapshot
expectSnap.Roots = newRoots
assertWatchChanRecvs(t, wCh, expectSnap)
assertWatchChanRecvs(t, wCh2, expectSnap)
// Update leaf
types.leaf.Set(leafCacheKey, newLeaf)
// Expect new roots in snapshot
expectSnap.ConnectProxy.Leaf = newLeaf
assertWatchChanRecvs(t, wCh, expectSnap)
assertWatchChanRecvs(t, wCh2, expectSnap)
// Remove the proxy
state.RemoveService(webProxy.CompoundServiceID())
// Chan should NOT close
assertWatchChanBlocks(t, wCh)
assertWatchChanBlocks(t, wCh2)
// Re-add the proxy with another new port
webProxy.Port = 3333
require.NoError(state.AddService(webProxy, "other-token"))
// Same watch chan should be notified again
expectSnap.Port = 3333
assertWatchChanRecvs(t, wCh, expectSnap)
assertWatchChanRecvs(t, wCh2, expectSnap)
// Cancel watch
cancel()
// Watch chan should be closed
assertWatchChanRecvs(t, wCh, nil)
// We specifically don't remove the proxy or cancel the second watcher to
// ensure both are cleaned up by close.
require.NoError(m.Close())
// Sanity check the state is clean
m.mu.Lock()
defer m.mu.Unlock()
require.Len(m.proxies, 0)
require.Len(m.watchers, 0)
}
func assertWatchChanBlocks(t *testing.T, ch <-chan *ConfigSnapshot) {
t.Helper()
select {
case <-ch:
t.Fatal("Should be nothing sent on watch chan yet")
default:
}
}
func assertWatchChanRecvs(t *testing.T, ch <-chan *ConfigSnapshot, expect *ConfigSnapshot) {
t.Helper()
select {
case got, ok := <-ch:
require.Equal(t, expect, got)
if expect == nil {
require.False(t, ok, "watch chan should be closed")
}
case <-time.After(100*time.Millisecond + coalesceTimeout):
t.Fatal("recv timeout")
}
}
func TestManager_deliverLatest(t *testing.T) {
// None of these need to do anything to test this method just be valid
logger := testutil.Logger(t)
cfg := ManagerConfig{
Cache: cache.New(cache.Options{EntryFetchRate: rate.Inf, EntryFetchMaxBurst: 2}),
State: local.NewState(local.Config{}, logger, &token.Store{}),
Source: &structs.QuerySource{
Node: "node1",
Datacenter: "dc1",
},
Logger: logger,
}
require := require.New(t)
m, err := NewManager(cfg)
require.NoError(err)
snap1 := &ConfigSnapshot{
ProxyID: structs.NewServiceID("test-proxy", nil),
Port: 1111,
}
snap2 := &ConfigSnapshot{
ProxyID: structs.NewServiceID("test-proxy", nil),
Port: 2222,
}
// test 1 buffered chan
ch1 := make(chan *ConfigSnapshot, 1)
// Sending to an unblocked chan should work
m.deliverLatest(snap1, ch1)
// Check it was delivered
require.Equal(snap1, <-ch1)
// Now send both without reading simulating a slow client
m.deliverLatest(snap1, ch1)
m.deliverLatest(snap2, ch1)
// Check we got the _second_ one
require.Equal(snap2, <-ch1)
// Same again for 5-buffered chan
ch5 := make(chan *ConfigSnapshot, 5)
// Sending to an unblocked chan should work
m.deliverLatest(snap1, ch5)
// Check it was delivered
require.Equal(snap1, <-ch5)
// Now send enough to fill the chan simulating a slow client
for i := 0; i < 5; i++ {
m.deliverLatest(snap1, ch5)
}
m.deliverLatest(snap2, ch5)
// Check we got the _second_ one
require.Equal(snap2, <-ch5)
}
func testGenCacheKey(req cache.Request) string {
info := req.CacheInfo()
return path.Join(info.Key, info.Datacenter)
}
func TestManager_SyncState_DefaultToken(t *testing.T) {
types := NewTestCacheTypes(t)
c := TestCacheWithTypes(t, types)
logger := testutil.Logger(t)
tokens := new(token.Store)
tokens.UpdateUserToken("default-token", token.TokenSourceConfig)
state := local.NewState(local.Config{}, logger, tokens)
state.TriggerSyncChanges = func() {}
m, err := NewManager(ManagerConfig{
Cache: c,
Health: &health.Client{Cache: c, CacheName: cachetype.HealthServicesName},
State: state,
Tokens: tokens,
Source: &structs.QuerySource{Datacenter: "dc1"},
Logger: logger,
})
require.NoError(t, err)
defer m.Close()
srv := &structs.NodeService{
Kind: structs.ServiceKindConnectProxy,
ID: "web-sidecar-proxy",
Service: "web-sidecar-proxy",
Port: 9999,
Meta: map[string]string{},
Proxy: structs.ConnectProxyConfig{
DestinationServiceID: "web",
DestinationServiceName: "web",
LocalServiceAddress: "127.0.0.1",
LocalServicePort: 8080,
Config: map[string]interface{}{
"foo": "bar",
},
},
}
err = state.AddServiceWithChecks(srv, nil, "")
require.NoError(t, err)
m.syncState(m.notifyBroadcast)
require.Equal(t, "default-token", m.proxies[srv.CompoundServiceID()].serviceInstance.token)
}
func TestManager_SyncState_No_Notify(t *testing.T) {
types := NewTestCacheTypes(t)
c := TestCacheWithTypes(t, types)
logger := testutil.Logger(t)
tokens := new(token.Store)
tokens.UpdateUserToken("default-token", token.TokenSourceConfig)
state := local.NewState(local.Config{}, logger, tokens)
state.TriggerSyncChanges = func() {}
m, err := NewManager(ManagerConfig{
Cache: c,
Health: &health.Client{Cache: c, CacheName: cachetype.HealthServicesName},
State: state,
Tokens: tokens,
Source: &structs.QuerySource{Datacenter: "dc1"},
Logger: logger,
})
require.NoError(t, err)
defer m.Close()
srv := &structs.NodeService{
Kind: structs.ServiceKindConnectProxy,
ID: "web-sidecar-proxy",
Service: "web-sidecar-proxy",
Port: 9999,
Meta: map[string]string{},
Proxy: structs.ConnectProxyConfig{
DestinationServiceID: "web",
DestinationServiceName: "web",
LocalServiceAddress: "127.0.0.1",
LocalServicePort: 8080,
Config: map[string]interface{}{
"foo": "bar",
},
},
}
err = state.AddServiceWithChecks(srv, nil, "")
require.NoError(t, err)
readEvent := make(chan bool, 1)
snapSent := make(chan bool, 1)
m.syncState(func(ch <-chan ConfigSnapshot) {
for {
<-readEvent
snap := <-ch
m.notify(&snap)
snapSent <- true
}
})
// Get the relevant notification Channel, should only have 1
notifyCH := m.proxies[srv.CompoundServiceID()].ch
// update the leaf certs
roots, issuedCert := TestCerts(t)
notifyCH <- cache.UpdateEvent{
CorrelationID: leafWatchID,
Result: issuedCert,
Err: nil,
}
// at this point the snapshot should not be valid and not be sent
after := time.After(200 * time.Millisecond)
select {
case <-snapSent:
t.Fatal("snap should not be valid")
case <-after:
}
// update the root certs
notifyCH <- cache.UpdateEvent{
CorrelationID: rootsWatchID,
Result: roots,
Err: nil,
}
// at this point the snapshot should not be valid and not be sent
after = time.After(200 * time.Millisecond)
select {
case <-snapSent:
t.Fatal("snap should not be valid")
case <-after:
}
// prepare to read a snapshot update as the next update should make the snapshot valid
readEvent <- true
// update the intentions
notifyCH <- cache.UpdateEvent{
CorrelationID: intentionsWatchID,
Result: &structs.IndexedIntentionMatches{},
Err: nil,
}
// at this point we have a valid snapshot
after = time.After(500 * time.Millisecond)
select {
case <-snapSent:
case <-after:
t.Fatal("snap should be valid")
}
// send two snapshots back to back without reading them to overflow the snapshot channel and get to the default use case
for i := 0; i < 2; i++ {
time.Sleep(250 * time.Millisecond)
notifyCH <- cache.UpdateEvent{
CorrelationID: leafWatchID,
Result: issuedCert,
Err: nil,
}
}
// make sure that we are not receiving any snapshot and wait for the snapshots to be processed
after = time.After(500 * time.Millisecond)
select {
case <-snapSent:
t.Fatal("snap should not be sent")
case <-after:
}
// now make sure that both snapshots got propagated
for i := 0; i < 2; i++ {
readEvent <- true
after = time.After(500 * time.Millisecond)
select {
case <-snapSent:
case <-after:
t.Fatal("snap should be valid")
}
}
}