dendrite/federationapi/queue/destinationqueue.go
0x1a8510f2 46902e5766
Take advantage of changes in recent Go versions (#3361)
Given that #2714 wasn't merged but we are now at a minimum supported Go
version of 1.20 (soon to be 1.21), I wanted to carry over some of the
changes. Namely:
- Fix the log typo
- Simplify build constraints for unix
- Use stdlib atomic package

### Pull Request Checklist

<!-- Please read
https://matrix-org.github.io/dendrite/development/contributing before
submitting your pull request -->

* [x] I have added Go unit tests or [Complement integration
tests](https://github.com/matrix-org/complement) for this PR _or_ I have
justified why this PR doesn't need tests
* [x] Pull request includes a [sign off below using a legally
identifiable
name](https://matrix-org.github.io/dendrite/development/contributing#sign-off)
_or_ I have already signed off privately

Signed-off-by: `0x1a8510f2 <admin@0x1a8510f2.space>`

---------

Co-authored-by: devonh <devon.dmytro@gmail.com>
2024-05-01 00:38:36 +00:00

607 lines
20 KiB
Go

// Copyright 2017 Vector Creations Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package queue
import (
"context"
"encoding/json"
"fmt"
"sync"
"sync/atomic"
"time"
"github.com/matrix-org/gomatrix"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/gomatrixserverlib/fclient"
"github.com/matrix-org/gomatrixserverlib/spec"
"github.com/sirupsen/logrus"
"github.com/matrix-org/dendrite/federationapi/statistics"
"github.com/matrix-org/dendrite/federationapi/storage"
"github.com/matrix-org/dendrite/federationapi/storage/shared/receipt"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/dendrite/setup/process"
)
const (
maxPDUsPerTransaction = 50
maxEDUsPerTransaction = 100
maxPDUsInMemory = 128
maxEDUsInMemory = 128
queueIdleTimeout = time.Second * 30
)
// destinationQueue is a queue of events for a single destination.
// It is responsible for sending the events to the destination and
// ensures that only one request is in flight to a given destination
// at a time.
type destinationQueue struct {
queues *OutgoingQueues
db storage.Database
process *process.ProcessContext
signing map[spec.ServerName]*fclient.SigningIdentity
client fclient.FederationClient // federation client
origin spec.ServerName // origin of requests
destination spec.ServerName // destination of requests
running atomic.Bool // is the queue worker running?
backingOff atomic.Bool // true if we're backing off
overflowed atomic.Bool // the queues exceed maxPDUsInMemory/maxEDUsInMemory, so we should consult the database for more
statistics *statistics.ServerStatistics // statistics about this remote server
transactionIDMutex sync.Mutex // protects transactionID
transactionID gomatrixserverlib.TransactionID // last transaction ID if retrying, or "" if last txn was successful
notify chan struct{} // interrupts idle wait pending PDUs/EDUs
pendingPDUs []*queuedPDU // PDUs waiting to be sent
pendingEDUs []*queuedEDU // EDUs waiting to be sent
pendingMutex sync.RWMutex // protects pendingPDUs and pendingEDUs
}
// Send event adds the event to the pending queue for the destination.
// If the queue is empty then it starts a background goroutine to
// start sending events to that destination.
func (oq *destinationQueue) sendEvent(event *types.HeaderedEvent, dbReceipt *receipt.Receipt) {
if event == nil {
logrus.Errorf("attempt to send nil PDU with destination %q", oq.destination)
return
}
// Check if the destination is blacklisted. If it isn't then wake
// up the queue.
if !oq.statistics.Blacklisted() {
// If there's room in memory to hold the event then add it to the
// list.
oq.pendingMutex.Lock()
if len(oq.pendingPDUs) < maxPDUsInMemory {
oq.pendingPDUs = append(oq.pendingPDUs, &queuedPDU{
pdu: event,
dbReceipt: dbReceipt,
})
} else {
oq.overflowed.Store(true)
}
oq.pendingMutex.Unlock()
if !oq.backingOff.Load() {
oq.wakeQueueAndNotify()
}
}
}
// sendEDU adds the EDU event to the pending queue for the destination.
// If the queue is empty then it starts a background goroutine to
// start sending events to that destination.
func (oq *destinationQueue) sendEDU(event *gomatrixserverlib.EDU, dbReceipt *receipt.Receipt) {
if event == nil {
logrus.Errorf("attempt to send nil EDU with destination %q", oq.destination)
return
}
// Check if the destination is blacklisted. If it isn't then wake
// up the queue.
if !oq.statistics.Blacklisted() {
// If there's room in memory to hold the event then add it to the
// list.
oq.pendingMutex.Lock()
if len(oq.pendingEDUs) < maxEDUsInMemory {
oq.pendingEDUs = append(oq.pendingEDUs, &queuedEDU{
edu: event,
dbReceipt: dbReceipt,
})
} else {
oq.overflowed.Store(true)
}
oq.pendingMutex.Unlock()
if !oq.backingOff.Load() {
oq.wakeQueueAndNotify()
}
}
}
// handleBackoffNotifier is registered as the backoff notification
// callback with Statistics. It will wakeup and notify the queue
// if the queue is currently backing off.
func (oq *destinationQueue) handleBackoffNotifier() {
// Only wake up the queue if it is backing off.
// Otherwise there is no pending work for the queue to handle
// so waking the queue would be a waste of resources.
if oq.backingOff.Load() {
oq.wakeQueueAndNotify()
}
}
// wakeQueueIfEventsPending calls wakeQueueAndNotify only if there are
// pending events or if forceWakeup is true. This prevents starting the
// queue unnecessarily.
func (oq *destinationQueue) wakeQueueIfEventsPending(forceWakeup bool) {
eventsPending := func() bool {
oq.pendingMutex.Lock()
defer oq.pendingMutex.Unlock()
return len(oq.pendingPDUs) > 0 || len(oq.pendingEDUs) > 0
}
// NOTE : Only wakeup and notify the queue if there are pending events
// or if forceWakeup is true. Otherwise there is no reason to start the
// queue goroutine and waste resources.
if forceWakeup || eventsPending() {
logrus.Info("Starting queue due to pending events or forceWakeup")
oq.wakeQueueAndNotify()
}
}
// wakeQueueAndNotify ensures the destination queue is running and notifies it
// that there is pending work.
func (oq *destinationQueue) wakeQueueAndNotify() {
// NOTE : Send notification before waking queue to prevent a race
// where the queue was running and stops due to a timeout in between
// checking it and sending the notification.
// Notify the queue that there are events ready to send.
select {
case oq.notify <- struct{}{}:
default:
}
// Wake up the queue if it's asleep.
oq.wakeQueueIfNeeded()
}
// wakeQueueIfNeeded will wake up the destination queue if it is
// not already running.
func (oq *destinationQueue) wakeQueueIfNeeded() {
// Clear the backingOff flag and update the backoff metrics if it was set.
if oq.backingOff.CompareAndSwap(true, false) {
destinationQueueBackingOff.Dec()
}
// If we aren't running then wake up the queue.
if !oq.running.Load() {
// Start the queue.
go oq.backgroundSend()
}
}
// getPendingFromDatabase will look at the database and see if
// there are any persisted events that haven't been sent to this
// destination yet. If so, they will be queued up.
func (oq *destinationQueue) getPendingFromDatabase() {
// Check to see if there's anything to do for this server
// in the database.
retrieved := false
ctx := oq.process.Context()
oq.pendingMutex.Lock()
defer oq.pendingMutex.Unlock()
// Take a note of all of the PDUs and EDUs that we already
// have cached. We will index them based on the receipt,
// which ultimately just contains the index of the PDU/EDU
// in the database.
gotPDUs := map[string]struct{}{}
gotEDUs := map[string]struct{}{}
for _, pdu := range oq.pendingPDUs {
gotPDUs[pdu.dbReceipt.String()] = struct{}{}
}
for _, edu := range oq.pendingEDUs {
gotEDUs[edu.dbReceipt.String()] = struct{}{}
}
overflowed := false
if pduCapacity := maxPDUsInMemory - len(oq.pendingPDUs); pduCapacity > 0 {
// We have room in memory for some PDUs - let's request no more than that.
if pdus, err := oq.db.GetPendingPDUs(ctx, oq.destination, maxPDUsInMemory); err == nil {
if len(pdus) == maxPDUsInMemory {
overflowed = true
}
for receipt, pdu := range pdus {
if _, ok := gotPDUs[receipt.String()]; ok {
continue
}
oq.pendingPDUs = append(oq.pendingPDUs, &queuedPDU{receipt, pdu})
retrieved = true
if len(oq.pendingPDUs) == maxPDUsInMemory {
break
}
}
} else {
logrus.WithError(err).Errorf("Failed to get pending PDUs for %q", oq.destination)
}
}
if eduCapacity := maxEDUsInMemory - len(oq.pendingEDUs); eduCapacity > 0 {
// We have room in memory for some EDUs - let's request no more than that.
if edus, err := oq.db.GetPendingEDUs(ctx, oq.destination, maxEDUsInMemory); err == nil {
if len(edus) == maxEDUsInMemory {
overflowed = true
}
for receipt, edu := range edus {
if _, ok := gotEDUs[receipt.String()]; ok {
continue
}
oq.pendingEDUs = append(oq.pendingEDUs, &queuedEDU{receipt, edu})
retrieved = true
if len(oq.pendingEDUs) == maxEDUsInMemory {
break
}
}
} else {
logrus.WithError(err).Errorf("Failed to get pending EDUs for %q", oq.destination)
}
}
// If we've retrieved all of the events from the database with room to spare
// in memory then we'll no longer consider this queue to be overflowed.
if !overflowed {
oq.overflowed.Store(false)
} else {
}
// If we've retrieved some events then notify the destination queue goroutine.
if retrieved {
select {
case oq.notify <- struct{}{}:
default:
}
}
}
// checkNotificationsOnClose checks for any remaining notifications
// and starts a new backgroundSend goroutine if any exist.
func (oq *destinationQueue) checkNotificationsOnClose() {
// NOTE : If we are stopping the queue due to blacklist then it
// doesn't matter if we have been notified of new work since
// this queue instance will be deleted anyway.
if !oq.statistics.Blacklisted() {
select {
case <-oq.notify:
// We received a new notification in between the
// idle timeout firing and stopping the goroutine.
// Immediately restart the queue.
oq.wakeQueueAndNotify()
default:
}
}
}
// backgroundSend is the worker goroutine for sending events.
func (oq *destinationQueue) backgroundSend() {
// Don't try to send transactions if we are shutting down.
if oq.process.Context().Err() != nil {
return
}
// Check if a worker is already running, and if it isn't, then
// mark it as started.
if !oq.running.CompareAndSwap(false, true) {
return
}
// Register queue cleanup functions.
// NOTE : The ordering here is very intentional.
defer oq.checkNotificationsOnClose()
defer oq.running.Store(false)
destinationQueueRunning.Inc()
defer destinationQueueRunning.Dec()
idleTimeout := time.NewTimer(queueIdleTimeout)
defer idleTimeout.Stop()
// Mark the queue as overflowed, so we will consult the database
// to see if there's anything new to send.
oq.overflowed.Store(true)
for {
// If we are overflowing memory and have sent things out to the
// database then we can look up what those things are.
if oq.overflowed.Load() {
oq.getPendingFromDatabase()
}
// Reset the queue idle timeout.
if !idleTimeout.Stop() {
select {
case <-idleTimeout.C:
default:
}
}
idleTimeout.Reset(queueIdleTimeout)
// If we have nothing to do then wait either for incoming events, or
// until we hit an idle timeout.
select {
case <-oq.notify:
// There's work to do, either because getPendingFromDatabase
// told us there is, a new event has come in via sendEvent/sendEDU,
// or we are backing off and it is time to retry.
case <-idleTimeout.C:
// The worker is idle so stop the goroutine. It'll get
// restarted automatically the next time we have an event to
// send.
return
case <-oq.process.Context().Done():
// The parent process is shutting down, so stop.
oq.statistics.ClearBackoff()
return
}
// Work out which PDUs/EDUs to include in the next transaction.
oq.pendingMutex.RLock()
pduCount := len(oq.pendingPDUs)
eduCount := len(oq.pendingEDUs)
if pduCount > maxPDUsPerTransaction {
pduCount = maxPDUsPerTransaction
}
if eduCount > maxEDUsPerTransaction {
eduCount = maxEDUsPerTransaction
}
toSendPDUs := oq.pendingPDUs[:pduCount]
toSendEDUs := oq.pendingEDUs[:eduCount]
oq.pendingMutex.RUnlock()
// If we didn't get anything from the database and there are no
// pending EDUs then there's nothing to do - stop here.
if pduCount == 0 && eduCount == 0 {
continue
}
// If we have pending PDUs or EDUs then construct a transaction.
// Try sending the next transaction and see what happens.
terr, sendMethod := oq.nextTransaction(toSendPDUs, toSendEDUs)
if terr != nil {
// We failed to send the transaction. Mark it as a failure.
_, blacklisted := oq.statistics.Failure()
if !blacklisted {
// Register the backoff state and exit the goroutine.
// It'll get restarted automatically when the backoff
// completes.
oq.backingOff.Store(true)
destinationQueueBackingOff.Inc()
return
} else {
// Immediately trigger the blacklist logic.
oq.blacklistDestination()
return
}
} else {
oq.handleTransactionSuccess(pduCount, eduCount, sendMethod)
}
}
}
// nextTransaction creates a new transaction from the pending event
// queue and sends it.
// Returns an error if the transaction wasn't sent. And whether the success
// was to a relay server or not.
func (oq *destinationQueue) nextTransaction(
pdus []*queuedPDU,
edus []*queuedEDU,
) (err error, sendMethod statistics.SendMethod) {
// Create the transaction.
t, pduReceipts, eduReceipts := oq.createTransaction(pdus, edus)
logrus.WithField("server_name", oq.destination).Debugf("Sending transaction %q containing %d PDUs, %d EDUs", t.TransactionID, len(t.PDUs), len(t.EDUs))
// Try to send the transaction to the destination server.
ctx, cancel := context.WithTimeout(oq.process.Context(), time.Minute*5)
defer cancel()
relayServers := oq.statistics.KnownRelayServers()
hasRelayServers := len(relayServers) > 0
shouldSendToRelays := oq.statistics.AssumedOffline() && hasRelayServers
if !shouldSendToRelays {
sendMethod = statistics.SendDirect
_, err = oq.client.SendTransaction(ctx, t)
} else {
// Try sending directly to the destination first in case they came back online.
sendMethod = statistics.SendDirect
_, err = oq.client.SendTransaction(ctx, t)
if err != nil {
// The destination is still offline, try sending to relays.
sendMethod = statistics.SendViaRelay
relaySuccess := false
logrus.Infof("Sending %q to relay servers: %v", t.TransactionID, relayServers)
// TODO : how to pass through actual userID here?!?!?!?!
userID, userErr := spec.NewUserID("@user:"+string(oq.destination), false)
if userErr != nil {
return userErr, sendMethod
}
// Attempt sending to each known relay server.
for _, relayServer := range relayServers {
_, relayErr := oq.client.P2PSendTransactionToRelay(ctx, *userID, t, relayServer)
if relayErr != nil {
err = relayErr
} else {
// If sending to one of the relay servers succeeds, consider the send successful.
relaySuccess = true
// TODO : what about if the dest comes back online but can't see their relay?
// How do I sync with the dest in that case?
// Should change the database to have a "relay success" flag on events and if
// I see the node back online, maybe directly send through the backlog of events
// with "relay success"... could lead to duplicate events, but only those that
// I sent. And will lead to a much more consistent experience.
}
}
// Clear the error if sending to any of the relay servers succeeded.
if relaySuccess {
err = nil
}
}
}
switch errResponse := err.(type) {
case nil:
// Clean up the transaction in the database.
if pduReceipts != nil {
//logrus.Infof("Cleaning PDUs %q", pduReceipt.String())
if err = oq.db.CleanPDUs(oq.process.Context(), oq.destination, pduReceipts); err != nil {
logrus.WithError(err).Errorf("Failed to clean PDUs for server %q", t.Destination)
}
}
if eduReceipts != nil {
//logrus.Infof("Cleaning EDUs %q", eduReceipt.String())
if err = oq.db.CleanEDUs(oq.process.Context(), oq.destination, eduReceipts); err != nil {
logrus.WithError(err).Errorf("Failed to clean EDUs for server %q", t.Destination)
}
}
// Reset the transaction ID.
oq.transactionIDMutex.Lock()
oq.transactionID = ""
oq.transactionIDMutex.Unlock()
return nil, sendMethod
case gomatrix.HTTPError:
// Report that we failed to send the transaction and we
// will retry again, subject to backoff.
// TODO: we should check for 500-ish fails vs 400-ish here,
// since we shouldn't queue things indefinitely in response
// to a 400-ish error
code := errResponse.Code
logrus.Debug("Transaction failed with HTTP", code)
return err, sendMethod
default:
logrus.WithFields(logrus.Fields{
"destination": oq.destination,
logrus.ErrorKey: err,
}).Debugf("Failed to send transaction %q", t.TransactionID)
return err, sendMethod
}
}
// createTransaction generates a gomatrixserverlib.Transaction from the provided pdus and edus.
// It also returns the associated event receipts so they can be cleaned from the database in
// the case of a successful transaction.
func (oq *destinationQueue) createTransaction(
pdus []*queuedPDU,
edus []*queuedEDU,
) (gomatrixserverlib.Transaction, []*receipt.Receipt, []*receipt.Receipt) {
// If there's no projected transaction ID then generate one. If
// the transaction succeeds then we'll set it back to "" so that
// we generate a new one next time. If it fails, we'll preserve
// it so that we retry with the same transaction ID.
oq.transactionIDMutex.Lock()
if oq.transactionID == "" {
now := spec.AsTimestamp(time.Now())
oq.transactionID = gomatrixserverlib.TransactionID(fmt.Sprintf("%d-%d", now, oq.statistics.SuccessCount()))
}
oq.transactionIDMutex.Unlock()
t := gomatrixserverlib.Transaction{
PDUs: []json.RawMessage{},
EDUs: []gomatrixserverlib.EDU{},
}
t.Origin = oq.origin
t.Destination = oq.destination
t.OriginServerTS = spec.AsTimestamp(time.Now())
t.TransactionID = oq.transactionID
var pduReceipts []*receipt.Receipt
var eduReceipts []*receipt.Receipt
// Go through PDUs that we retrieved from the database, if any,
// and add them into the transaction.
for _, pdu := range pdus {
// These should never be nil.
if pdu == nil || pdu.pdu == nil {
continue
}
// Append the JSON of the event, since this is a json.RawMessage type in the
// gomatrixserverlib.Transaction struct
t.PDUs = append(t.PDUs, pdu.pdu.JSON())
pduReceipts = append(pduReceipts, pdu.dbReceipt)
}
// Do the same for pending EDUS in the queue.
for _, edu := range edus {
// These should never be nil.
if edu == nil || edu.edu == nil {
continue
}
t.EDUs = append(t.EDUs, *edu.edu)
eduReceipts = append(eduReceipts, edu.dbReceipt)
}
return t, pduReceipts, eduReceipts
}
// blacklistDestination removes all pending PDUs and EDUs that have been cached
// and deletes this queue.
func (oq *destinationQueue) blacklistDestination() {
// It's been suggested that we should give up because the backoff
// has exceeded a maximum allowable value. Clean up the in-memory
// buffers at this point. The PDU clean-up is already on a defer.
logrus.Warnf("Blacklisting %q due to exceeding backoff threshold", oq.destination)
oq.pendingMutex.Lock()
for i := range oq.pendingPDUs {
oq.pendingPDUs[i] = nil
}
for i := range oq.pendingEDUs {
oq.pendingEDUs[i] = nil
}
oq.pendingPDUs = nil
oq.pendingEDUs = nil
oq.pendingMutex.Unlock()
// Delete this queue as no more messages will be sent to this
// destination until it is no longer blacklisted.
oq.statistics.AssignBackoffNotifier(nil)
oq.queues.clearQueue(oq)
}
// handleTransactionSuccess updates the cached event queues as well as the success and
// backoff information for this server.
func (oq *destinationQueue) handleTransactionSuccess(pduCount int, eduCount int, sendMethod statistics.SendMethod) {
// If we successfully sent the transaction then clear out
// the pending events and EDUs, and wipe our transaction ID.
oq.statistics.Success(sendMethod)
oq.pendingMutex.Lock()
defer oq.pendingMutex.Unlock()
for i := range oq.pendingPDUs[:pduCount] {
oq.pendingPDUs[i] = nil
}
for i := range oq.pendingEDUs[:eduCount] {
oq.pendingEDUs[i] = nil
}
oq.pendingPDUs = oq.pendingPDUs[pduCount:]
oq.pendingEDUs = oq.pendingEDUs[eduCount:]
if len(oq.pendingPDUs) > 0 || len(oq.pendingEDUs) > 0 {
select {
case oq.notify <- struct{}{}:
default:
}
}
}