func TestFollower(t *testing.T) {
store, err := kv.NewStore("mock", []string{}, nil)
assert.NoError(t, err)
mockStore := store.(*kv.Mock)
kvCh := make(chan *kv.KVPair)
var mockKVCh <-chan *kv.KVPair = kvCh
mockStore.On("Watch", "test_key", mock.Anything).Return(mockKVCh, nil)
follower := NewFollower(store, "test_key")
follower.FollowElection()
leaderCh := follower.LeaderCh()
// Simulate leader updates
go func() {
kvCh <- &kv.KVPair{Key: "test_key", Value: []byte("leader1")}
kvCh <- &kv.KVPair{Key: "test_key", Value: []byte("leader1")}
kvCh <- &kv.KVPair{Key: "test_key", Value: []byte("leader2")}
kvCh <- &kv.KVPair{Key: "test_key", Value: []byte("leader1")}
}()
// We shouldn't see duplicate events.
assert.Equal(t, <-leaderCh, "leader1")
assert.Equal(t, <-leaderCh, "leader2")
assert.Equal(t, <-leaderCh, "leader1")
// Once stopped, iteration over the leader channel should stop.
follower.Stop()
close(kvCh)
assert.Equal(t, "", <-leaderCh)
mockStore.AssertExpectations(t)
}
// Initialize is exported
func (s *Discovery) Initialize(uris string, heartbeat time.Duration, ttl time.Duration) error {
var (
parts = strings.SplitN(uris, "/", 2)
addrs = strings.Split(parts[0], ",")
prefix = ""
err error
)
// A custom prefix to the path can be optionally used.
if len(parts) == 2 {
prefix = parts[1]
}
s.heartbeat = heartbeat
s.ttl = ttl
s.path = path.Join(prefix, discoveryPath)
// Creates a new store, will ignore options given
// if not supported by the chosen store
s.store, err = store.NewStore(
s.backend,
addrs,
&store.Config{
EphemeralTTL: s.ttl,
},
)
return err
}
func TestCandidate(t *testing.T) {
store, err := kv.NewStore("mock", []string{}, nil)
assert.NoError(t, err)
mockStore := store.(*kv.Mock)
mockLock := &kv.MockLock{}
mockStore.On("NewLock", "test_key", mock.Anything).Return(mockLock, nil)
// Lock and unlock always succeeds.
lostCh := make(chan struct{})
var mockLostCh <-chan struct{} = lostCh
mockLock.On("Lock").Return(mockLostCh, nil)
mockLock.On("Unlock").Return(nil)
candidate := NewCandidate(store, "test_key", "test_node")
candidate.RunForElection()
electedCh := candidate.ElectedCh()
// Should issue a false upon start, no matter what.
assert.False(t, <-electedCh)
// Since the lock always succeeeds, we should get elected.
assert.True(t, <-electedCh)
// Signaling a lost lock should get us de-elected...
close(lostCh)
assert.False(t, <-electedCh)
// And we should attempt to get re-elected again.
assert.True(t, <-electedCh)
// When we resign, unlock will get called, we'll be notified of the
// de-election and we'll try to get the lock again.
go candidate.Resign()
assert.False(t, <-electedCh)
assert.True(t, <-electedCh)
// After stopping the candidate, the ElectedCh should be closed.
candidate.Stop()
select {
case <-electedCh:
assert.True(t, false) // we should not get here.
default:
assert.True(t, true)
}
mockStore.AssertExpectations(t)
}