coder/coderd/database/pubsub/pubsub_internal_test.go

258 lines
7.1 KiB
Go

package pubsub
import (
"context"
"fmt"
"sync"
"testing"
"github.com/lib/pq"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"cdr.dev/slog"
"cdr.dev/slog/sloggers/slogtest"
"github.com/coder/coder/v2/testutil"
)
func Test_msgQueue_ListenerWithError(t *testing.T) {
t.Parallel()
ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
defer cancel()
m := make(chan string)
e := make(chan error)
uut := newMsgQueue(ctx, nil, func(ctx context.Context, msg []byte, err error) {
m <- string(msg)
e <- err
})
defer uut.close()
// We're going to enqueue 4 messages and an error in a loop -- that is, a cycle of 5.
// PubsubBufferSize is 2048, which is a power of 2, so a pattern of 5 will not be aligned
// when we wrap around the end of the circular buffer. This tests that we correctly handle
// the wrapping and aren't dequeueing misaligned data.
cycles := (BufferSize / 5) * 2 // almost twice around the ring
for j := 0; j < cycles; j++ {
for i := 0; i < 4; i++ {
uut.enqueue([]byte(fmt.Sprintf("%d%d", j, i)))
}
uut.dropped()
for i := 0; i < 4; i++ {
select {
case <-ctx.Done():
t.Fatal("timed out")
case msg := <-m:
require.Equal(t, fmt.Sprintf("%d%d", j, i), msg)
}
select {
case <-ctx.Done():
t.Fatal("timed out")
case err := <-e:
require.NoError(t, err)
}
}
select {
case <-ctx.Done():
t.Fatal("timed out")
case msg := <-m:
require.Equal(t, "", msg)
}
select {
case <-ctx.Done():
t.Fatal("timed out")
case err := <-e:
require.ErrorIs(t, err, ErrDroppedMessages)
}
}
}
func Test_msgQueue_Listener(t *testing.T) {
t.Parallel()
ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
defer cancel()
m := make(chan string)
uut := newMsgQueue(ctx, func(ctx context.Context, msg []byte) {
m <- string(msg)
}, nil)
defer uut.close()
// We're going to enqueue 4 messages and an error in a loop -- that is, a cycle of 5.
// PubsubBufferSize is 2048, which is a power of 2, so a pattern of 5 will not be aligned
// when we wrap around the end of the circular buffer. This tests that we correctly handle
// the wrapping and aren't dequeueing misaligned data.
cycles := (BufferSize / 5) * 2 // almost twice around the ring
for j := 0; j < cycles; j++ {
for i := 0; i < 4; i++ {
uut.enqueue([]byte(fmt.Sprintf("%d%d", j, i)))
}
uut.dropped()
for i := 0; i < 4; i++ {
select {
case <-ctx.Done():
t.Fatal("timed out")
case msg := <-m:
require.Equal(t, fmt.Sprintf("%d%d", j, i), msg)
}
}
// Listener skips over errors, so we only read out the 4 real messages.
}
}
func Test_msgQueue_Full(t *testing.T) {
t.Parallel()
ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
defer cancel()
firstDequeue := make(chan struct{})
allowRead := make(chan struct{})
n := 0
errors := make(chan error)
uut := newMsgQueue(ctx, nil, func(ctx context.Context, msg []byte, err error) {
if n == 0 {
close(firstDequeue)
}
<-allowRead
if err == nil {
require.Equal(t, fmt.Sprintf("%d", n), string(msg))
n++
return
}
errors <- err
})
defer uut.close()
// we send 2 more than the capacity. One extra because the call to the ListenerFunc blocks
// but only after we've dequeued a message, and then another extra because we want to exceed
// the capacity, not just reach it.
for i := 0; i < BufferSize+2; i++ {
uut.enqueue([]byte(fmt.Sprintf("%d", i)))
// ensure the first dequeue has happened before proceeding, so that this function isn't racing
// against the goroutine that dequeues items.
<-firstDequeue
}
close(allowRead)
select {
case <-ctx.Done():
t.Fatal("timed out")
case err := <-errors:
require.ErrorIs(t, err, ErrDroppedMessages)
}
// Ok, so we sent 2 more than capacity, but we only read the capacity, that's because the last
// message we send doesn't get queued, AND, it bumps a message out of the queue to make room
// for the error, so we read 2 less than we sent.
require.Equal(t, BufferSize, n)
}
func TestPubSub_DoesntBlockNotify(t *testing.T) {
t.Parallel()
ctx := testutil.Context(t, testutil.WaitShort)
logger := slogtest.Make(t, nil).Leveled(slog.LevelDebug)
uut := newWithoutListener(logger, nil)
fListener := newFakePqListener()
uut.pgListener = fListener
go uut.listen()
cancels := make(chan func())
go func() {
subCancel, err := uut.Subscribe("bagels", func(ctx context.Context, message []byte) {
t.Logf("got message: %s", string(message))
})
assert.NoError(t, err)
cancels <- subCancel
}()
subCancel := testutil.RequireRecvCtx(ctx, t, cancels)
cancelDone := make(chan struct{})
go func() {
defer close(cancelDone)
subCancel()
}()
testutil.RequireRecvCtx(ctx, t, cancelDone)
closeErrs := make(chan error)
go func() {
closeErrs <- uut.Close()
}()
err := testutil.RequireRecvCtx(ctx, t, closeErrs)
require.NoError(t, err)
}
const (
numNotifications = 5
testMessage = "birds of a feather"
)
// fakePqListener is a fake version of pq.Listener. This test code tests for regressions of
// https://github.com/coder/coder/issues/11950 where pq.Listener deadlocked because we blocked the
// PGPubsub.listen() goroutine while calling other pq.Listener functions. So, all function calls
// into the fakePqListener will send 5 notifications before returning to ensure the listen()
// goroutine is unblocked.
type fakePqListener struct {
mu sync.Mutex
channels map[string]struct{}
notify chan *pq.Notification
}
func (f *fakePqListener) Close() error {
f.mu.Lock()
defer f.mu.Unlock()
ch := f.getTestChanLocked()
for i := 0; i < numNotifications; i++ {
f.notify <- &pq.Notification{Channel: ch, Extra: testMessage}
}
// note that the realPqListener must only be closed once, so go ahead and
// close the notify unprotected here. If it panics, we have a bug.
close(f.notify)
return nil
}
func (f *fakePqListener) Listen(s string) error {
f.mu.Lock()
defer f.mu.Unlock()
ch := f.getTestChanLocked()
for i := 0; i < numNotifications; i++ {
f.notify <- &pq.Notification{Channel: ch, Extra: testMessage}
}
if _, ok := f.channels[s]; ok {
return pq.ErrChannelAlreadyOpen
}
f.channels[s] = struct{}{}
return nil
}
func (f *fakePqListener) Unlisten(s string) error {
f.mu.Lock()
defer f.mu.Unlock()
ch := f.getTestChanLocked()
for i := 0; i < numNotifications; i++ {
f.notify <- &pq.Notification{Channel: ch, Extra: testMessage}
}
if _, ok := f.channels[s]; ok {
delete(f.channels, s)
return nil
}
return pq.ErrChannelNotOpen
}
func (f *fakePqListener) NotifyChan() <-chan *pq.Notification {
return f.notify
}
// getTestChanLocked returns the name of a channel we are currently listening for, if there is one.
// Otherwise, it just returns "test". We prefer to send test notifications for channels that appear
// in the tests, but if there are none, just return anything.
func (f *fakePqListener) getTestChanLocked() string {
for c := range f.channels {
return c
}
return "test"
}
func newFakePqListener() *fakePqListener {
return &fakePqListener{
channels: make(map[string]struct{}),
notify: make(chan *pq.Notification),
}
}