zitadel/internal/eventstore/handler/v2/handler.go

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package handler
import (
"context"
"database/sql"
"errors"
"math"
"math/rand"
"slices"
"sync"
"time"
"github.com/jackc/pgx/v5/pgconn"
"github.com/zitadel/logging"
"github.com/zitadel/zitadel/internal/api/authz"
"github.com/zitadel/zitadel/internal/api/call"
"github.com/zitadel/zitadel/internal/database"
"github.com/zitadel/zitadel/internal/eventstore"
"github.com/zitadel/zitadel/internal/migration"
"github.com/zitadel/zitadel/internal/repository/instance"
"github.com/zitadel/zitadel/internal/repository/pseudo"
)
type EventStore interface {
InstanceIDs(ctx context.Context, query *eventstore.SearchQueryBuilder) ([]string, error)
FilterToQueryReducer(ctx context.Context, reducer eventstore.QueryReducer) error
Filter(ctx context.Context, queryFactory *eventstore.SearchQueryBuilder) ([]eventstore.Event, error)
Push(ctx context.Context, cmds ...eventstore.Command) ([]eventstore.Event, error)
FillFields(ctx context.Context, events ...eventstore.FillFieldsEvent) error
}
type Config struct {
Client *database.DB
Eventstore EventStore
BulkLimit uint16
RequeueEvery time.Duration
RetryFailedAfter time.Duration
TransactionDuration time.Duration
MaxFailureCount uint8
TriggerWithoutEvents Reduce
ActiveInstancer interface {
ActiveInstances() []string
}
}
type Handler struct {
client *database.DB
projection Projection
es EventStore
bulkLimit uint16
eventTypes map[eventstore.AggregateType][]eventstore.EventType
maxFailureCount uint8
retryFailedAfter time.Duration
requeueEvery time.Duration
txDuration time.Duration
now nowFunc
triggeredInstancesSync sync.Map
triggerWithoutEvents Reduce
cacheInvalidations []func(ctx context.Context, aggregates []*eventstore.Aggregate)
queryInstances func() ([]string, error)
}
var _ migration.Migration = (*Handler)(nil)
// Execute implements migration.Migration.
func (h *Handler) Execute(ctx context.Context, startedEvent eventstore.Event) error {
start := time.Now()
logging.WithFields("projection", h.ProjectionName()).Info("projection starts prefilling")
logTicker := time.NewTicker(30 * time.Second)
go func() {
for range logTicker.C {
logging.WithFields("projection", h.ProjectionName()).Info("projection is prefilling")
}
}()
instanceIDs, err := h.existingInstances(ctx)
if err != nil {
return err
}
// default amount of workers is 10
workerCount := 10
if h.client.DB.Stats().MaxOpenConnections > 0 {
workerCount = h.client.DB.Stats().MaxOpenConnections / 4
}
// ensure that at least one worker is active
if workerCount == 0 {
workerCount = 1
}
// spawn less workers if not all workers needed
if workerCount > len(instanceIDs) {
workerCount = len(instanceIDs)
}
instances := make(chan string, workerCount)
var wg sync.WaitGroup
wg.Add(workerCount)
for i := 0; i < workerCount; i++ {
go h.executeInstances(ctx, instances, startedEvent, &wg)
}
for _, instance := range instanceIDs {
instances <- instance
}
close(instances)
wg.Wait()
logTicker.Stop()
logging.WithFields("projection", h.ProjectionName(), "took", time.Since(start)).Info("projections ended prefilling")
return nil
}
func (h *Handler) executeInstances(ctx context.Context, instances <-chan string, startedEvent eventstore.Event, wg *sync.WaitGroup) {
for instance := range instances {
h.triggerInstances(ctx, []string{instance}, WithMaxPosition(startedEvent.Position()))
}
wg.Done()
}
// String implements migration.Migration.
func (h *Handler) String() string {
return h.ProjectionName()
}
// nowFunc makes [time.Now] mockable
type nowFunc func() time.Time
type Projection interface {
Name() string
Reducers() []AggregateReducer
}
func NewHandler(
ctx context.Context,
config *Config,
projection Projection,
) *Handler {
aggregates := make(map[eventstore.AggregateType][]eventstore.EventType, len(projection.Reducers()))
for _, reducer := range projection.Reducers() {
eventTypes := make([]eventstore.EventType, len(reducer.EventReducers))
for i, eventReducer := range reducer.EventReducers {
eventTypes[i] = eventReducer.Event
}
if _, ok := aggregates[reducer.Aggregate]; ok {
aggregates[reducer.Aggregate] = append(aggregates[reducer.Aggregate], eventTypes...)
continue
}
aggregates[reducer.Aggregate] = eventTypes
}
handler := &Handler{
projection: projection,
client: config.Client,
es: config.Eventstore,
bulkLimit: config.BulkLimit,
eventTypes: aggregates,
requeueEvery: config.RequeueEvery,
now: time.Now,
maxFailureCount: config.MaxFailureCount,
retryFailedAfter: config.RetryFailedAfter,
triggeredInstancesSync: sync.Map{},
triggerWithoutEvents: config.TriggerWithoutEvents,
txDuration: config.TransactionDuration,
queryInstances: func() ([]string, error) {
if config.ActiveInstancer != nil {
return config.ActiveInstancer.ActiveInstances(), nil
}
return nil, nil
},
}
return handler
}
func (h *Handler) Start(ctx context.Context) {
go h.schedule(ctx)
if h.triggerWithoutEvents != nil {
return
}
go h.subscribe(ctx)
}
type checkInit struct {
didInit bool
projectionName string
}
// AppendEvents implements eventstore.QueryReducer.
func (ci *checkInit) AppendEvents(...eventstore.Event) {
ci.didInit = true
}
// Query implements eventstore.QueryReducer.
func (ci *checkInit) Query() *eventstore.SearchQueryBuilder {
return eventstore.NewSearchQueryBuilder(eventstore.ColumnsEvent).
Limit(1).
InstanceID("").
AddQuery().
AggregateTypes(migration.SystemAggregate).
AggregateIDs(migration.SystemAggregateID).
EventTypes(migration.DoneType).
EventData(map[string]interface{}{
"name": ci.projectionName,
}).
Builder()
}
// Reduce implements eventstore.QueryReducer.
func (*checkInit) Reduce() error {
return nil
}
var _ eventstore.QueryReducer = (*checkInit)(nil)
func (h *Handler) didInitialize(ctx context.Context) bool {
initiated := checkInit{
projectionName: h.ProjectionName(),
}
err := h.es.FilterToQueryReducer(ctx, &initiated)
if err != nil {
return false
}
return initiated.didInit
}
func (h *Handler) schedule(ctx context.Context) {
// start the projection and its configured `RequeueEvery`
reset := randomizeStart(0, h.requeueEvery.Seconds())
if !h.didInitialize(ctx) {
reset = randomizeStart(0, 0.5)
}
t := time.NewTimer(reset)
for {
select {
case <-ctx.Done():
t.Stop()
return
case <-t.C:
instances, err := h.queryInstances()
h.log().OnError(err).Debug("unable to query instances")
h.triggerInstances(call.WithTimestamp(ctx), instances)
t.Reset(h.requeueEvery)
}
}
}
func (h *Handler) triggerInstances(ctx context.Context, instances []string, triggerOpts ...TriggerOpt) {
for _, instance := range instances {
instanceCtx := authz.WithInstanceID(ctx, instance)
// simple implementation of do while
_, err := h.Trigger(instanceCtx, triggerOpts...)
h.log().WithField("instance", instance).OnError(err).Debug("trigger failed")
time.Sleep(h.retryFailedAfter)
// retry if trigger failed
for ; err != nil; _, err = h.Trigger(instanceCtx, triggerOpts...) {
time.Sleep(h.retryFailedAfter)
h.log().WithField("instance", instance).OnError(err).Debug("trigger failed")
}
}
}
func randomizeStart(min, maxSeconds float64) time.Duration {
d := min + rand.Float64()*(maxSeconds-min)
return time.Duration(d*1000) * time.Millisecond
}
func (h *Handler) subscribe(ctx context.Context) {
queue := make(chan eventstore.Event, 100)
subscription := eventstore.SubscribeEventTypes(queue, h.eventTypes)
for {
select {
case <-ctx.Done():
subscription.Unsubscribe()
h.log().Debug("shutdown")
return
case event := <-queue:
events := checkAdditionalEvents(queue, event)
solvedInstances := make([]string, 0, len(events))
queueCtx := call.WithTimestamp(ctx)
for _, e := range events {
if instanceSolved(solvedInstances, e.Aggregate().InstanceID) {
continue
}
queueCtx = authz.WithInstanceID(queueCtx, e.Aggregate().InstanceID)
_, err := h.Trigger(queueCtx)
h.log().OnError(err).Debug("trigger of queued event failed")
if err == nil {
solvedInstances = append(solvedInstances, e.Aggregate().InstanceID)
}
}
}
}
}
func instanceSolved(solvedInstances []string, instanceID string) bool {
for _, solvedInstance := range solvedInstances {
if solvedInstance == instanceID {
return true
}
}
return false
}
func checkAdditionalEvents(eventQueue chan eventstore.Event, event eventstore.Event) []eventstore.Event {
events := make([]eventstore.Event, 1)
events[0] = event
for {
wait := time.NewTimer(1 * time.Millisecond)
select {
case event := <-eventQueue:
events = append(events, event)
case <-wait.C:
return events
}
}
}
type existingInstances []string
// AppendEvents implements eventstore.QueryReducer.
func (ai *existingInstances) AppendEvents(events ...eventstore.Event) {
for _, event := range events {
switch event.Type() {
case instance.InstanceAddedEventType:
*ai = append(*ai, event.Aggregate().InstanceID)
case instance.InstanceRemovedEventType:
*ai = slices.DeleteFunc(*ai, func(s string) bool {
return s == event.Aggregate().InstanceID
})
}
}
}
// Query implements eventstore.QueryReducer.
func (*existingInstances) Query() *eventstore.SearchQueryBuilder {
return eventstore.NewSearchQueryBuilder(eventstore.ColumnsEvent).
AddQuery().
AggregateTypes(instance.AggregateType).
EventTypes(
instance.InstanceAddedEventType,
instance.InstanceRemovedEventType,
).
Builder()
}
// Reduce implements eventstore.QueryReducer.
// reduce is not used as events are reduced during AppendEvents
func (*existingInstances) Reduce() error {
return nil
}
var _ eventstore.QueryReducer = (*existingInstances)(nil)
func (h *Handler) existingInstances(ctx context.Context) ([]string, error) {
ai := existingInstances{}
if err := h.es.FilterToQueryReducer(ctx, &ai); err != nil {
return nil, err
}
return ai, nil
}
type triggerConfig struct {
awaitRunning bool
maxPosition float64
}
type TriggerOpt func(conf *triggerConfig)
func WithAwaitRunning() TriggerOpt {
return func(conf *triggerConfig) {
conf.awaitRunning = true
}
}
func WithMaxPosition(position float64) TriggerOpt {
return func(conf *triggerConfig) {
conf.maxPosition = position
}
}
func (h *Handler) Trigger(ctx context.Context, opts ...TriggerOpt) (_ context.Context, err error) {
config := new(triggerConfig)
for _, opt := range opts {
opt(config)
}
cancel := h.lockInstance(ctx, config)
if cancel == nil {
return call.ResetTimestamp(ctx), nil
}
defer cancel()
for i := 0; ; i++ {
additionalIteration, err := h.processEvents(ctx, config)
h.log().OnError(err).Info("process events failed")
h.log().WithField("iteration", i).Debug("trigger iteration")
if !additionalIteration || err != nil {
return call.ResetTimestamp(ctx), err
}
}
}
// RegisterCacheInvalidation registers a function to be called when a cache needs to be invalidated.
// In order to avoid race conditions, this method must be called before [Handler.Start] is called.
func (h *Handler) RegisterCacheInvalidation(invalidate func(ctx context.Context, aggregates []*eventstore.Aggregate)) {
h.cacheInvalidations = append(h.cacheInvalidations, invalidate)
}
// lockInstance tries to lock the instance.
// If the instance is already locked from another process no cancel function is returned
// the instance can be skipped then
// If the instance is locked, an unlock deferrable function is returned
func (h *Handler) lockInstance(ctx context.Context, config *triggerConfig) func() {
instanceID := authz.GetInstance(ctx).InstanceID()
// Check that the instance has a lock
instanceLock, _ := h.triggeredInstancesSync.LoadOrStore(instanceID, make(chan bool, 1))
// in case we don't want to wait for a running trigger / lock (e.g. spooler),
// we can directly return if we cannot lock
if !config.awaitRunning {
select {
case instanceLock.(chan bool) <- true:
return func() {
<-instanceLock.(chan bool)
}
default:
return nil
}
}
// in case we want to wait for a running trigger / lock (e.g. query),
// we try to lock as long as the context is not cancelled
select {
case instanceLock.(chan bool) <- true:
return func() {
<-instanceLock.(chan bool)
}
case <-ctx.Done():
return nil
}
}
func (h *Handler) processEvents(ctx context.Context, config *triggerConfig) (additionalIteration bool, err error) {
defer func() {
pgErr := new(pgconn.PgError)
if errors.As(err, &pgErr) {
// error returned if the row is currently locked by another connection
if pgErr.Code == "55P03" {
h.log().Debug("state already locked")
err = nil
additionalIteration = false
}
}
}()
txCtx := ctx
if h.txDuration > 0 {
var cancel, cancelTx func()
// add 100ms to store current state if iteration takes too long
txCtx, cancelTx = context.WithTimeout(ctx, h.txDuration+100*time.Millisecond)
defer cancelTx()
ctx, cancel = context.WithTimeout(ctx, h.txDuration)
defer cancel()
}
tx, err := h.client.BeginTx(txCtx, nil)
if err != nil {
return false, err
}
defer func() {
if err != nil && !errors.Is(err, &executionError{}) {
rollbackErr := tx.Rollback()
h.log().OnError(rollbackErr).Debug("unable to rollback tx")
return
}
}()
currentState, err := h.currentState(ctx, tx, config)
if err != nil {
if errors.Is(err, errJustUpdated) {
return false, nil
}
return additionalIteration, err
}
// stop execution if currentState.eventTimestamp >= config.maxCreatedAt
if config.maxPosition != 0 && currentState.position >= config.maxPosition {
return false, nil
}
var statements []*Statement
statements, additionalIteration, err = h.generateStatements(ctx, tx, currentState)
if err != nil {
return additionalIteration, err
}
defer func() {
commitErr := tx.Commit()
if err == nil {
err = commitErr
}
if err == nil && currentState.aggregateID != "" && len(statements) > 0 {
h.invalidateCaches(ctx, aggregatesFromStatements(statements))
}
}()
if len(statements) == 0 {
err = h.setState(tx, currentState)
return additionalIteration, err
}
lastProcessedIndex, err := h.executeStatements(ctx, tx, statements)
h.log().OnError(err).WithField("lastProcessedIndex", lastProcessedIndex).Debug("execution of statements failed")
if lastProcessedIndex < 0 {
return false, err
}
currentState.position = statements[lastProcessedIndex].Position
currentState.offset = statements[lastProcessedIndex].offset
currentState.aggregateID = statements[lastProcessedIndex].Aggregate.ID
currentState.aggregateType = statements[lastProcessedIndex].Aggregate.Type
currentState.sequence = statements[lastProcessedIndex].Sequence
currentState.eventTimestamp = statements[lastProcessedIndex].CreationDate
err = h.setState(tx, currentState)
return additionalIteration, err
}
func (h *Handler) generateStatements(ctx context.Context, tx *sql.Tx, currentState *state) (_ []*Statement, additionalIteration bool, err error) {
if h.triggerWithoutEvents != nil {
stmt, err := h.triggerWithoutEvents(pseudo.NewScheduledEvent(ctx, time.Now(), currentState.instanceID))
if err != nil {
return nil, false, err
}
return []*Statement{stmt}, false, nil
}
events, err := h.es.Filter(ctx, h.eventQuery(currentState).SetTx(tx))
if err != nil {
h.log().WithError(err).Debug("filter eventstore failed")
return nil, false, err
}
eventAmount := len(events)
statements, err := h.eventsToStatements(tx, events, currentState)
if err != nil || len(statements) == 0 {
return nil, false, err
}
idx := skipPreviouslyReducedStatements(statements, currentState)
if idx+1 == len(statements) {
currentState.position = statements[len(statements)-1].Position
currentState.offset = statements[len(statements)-1].offset
currentState.aggregateID = statements[len(statements)-1].Aggregate.ID
currentState.aggregateType = statements[len(statements)-1].Aggregate.Type
currentState.sequence = statements[len(statements)-1].Sequence
currentState.eventTimestamp = statements[len(statements)-1].CreationDate
return nil, false, nil
}
statements = statements[idx+1:]
additionalIteration = eventAmount == int(h.bulkLimit)
if len(statements) < len(events) {
// retry immediately if statements failed
additionalIteration = true
}
return statements, additionalIteration, nil
}
func skipPreviouslyReducedStatements(statements []*Statement, currentState *state) int {
for i, statement := range statements {
if statement.Position == currentState.position &&
statement.Aggregate.ID == currentState.aggregateID &&
statement.Aggregate.Type == currentState.aggregateType &&
statement.Sequence == currentState.sequence {
return i
}
}
return -1
}
func (h *Handler) executeStatements(ctx context.Context, tx *sql.Tx, statements []*Statement) (lastProcessedIndex int, err error) {
lastProcessedIndex = -1
for i, statement := range statements {
select {
case <-ctx.Done():
break
default:
err := h.executeStatement(ctx, tx, statement)
if err != nil {
return lastProcessedIndex, err
}
lastProcessedIndex = i
}
}
return lastProcessedIndex, nil
}
func (h *Handler) executeStatement(ctx context.Context, tx *sql.Tx, statement *Statement) (err error) {
if statement.Execute == nil {
return nil
}
_, err = tx.ExecContext(ctx, "SAVEPOINT exec_stmt")
if err != nil {
h.log().WithError(err).Debug("create savepoint failed")
return err
}
if err = statement.Execute(tx, h.projection.Name()); err != nil {
h.log().WithError(err).Error("statement execution failed")
_, rollbackErr := tx.ExecContext(ctx, "ROLLBACK TO SAVEPOINT exec_stmt")
h.log().OnError(rollbackErr).Error("rollback to savepoint failed")
shouldContinue := h.handleFailedStmt(tx, failureFromStatement(statement, err))
if shouldContinue {
return nil
}
return &executionError{parent: err}
}
return nil
}
func (h *Handler) eventQuery(currentState *state) *eventstore.SearchQueryBuilder {
builder := eventstore.NewSearchQueryBuilder(eventstore.ColumnsEvent).
AwaitOpenTransactions().
Limit(uint64(h.bulkLimit)).
AllowTimeTravel().
OrderAsc().
InstanceID(currentState.instanceID)
if currentState.position > 0 {
// decrease position by 10 because builder.PositionAfter filters for position > and we need position >=
builder = builder.PositionAfter(math.Float64frombits(math.Float64bits(currentState.position) - 10))
if currentState.offset > 0 {
builder = builder.Offset(currentState.offset)
}
}
for aggregateType, eventTypes := range h.eventTypes {
builder = builder.
AddQuery().
AggregateTypes(aggregateType).
EventTypes(eventTypes...).
Builder()
}
return builder
}
// ProjectionName returns the name of the underlying projection.
func (h *Handler) ProjectionName() string {
return h.projection.Name()
}
func (h *Handler) invalidateCaches(ctx context.Context, aggregates []*eventstore.Aggregate) {
if len(h.cacheInvalidations) == 0 {
return
}
var wg sync.WaitGroup
wg.Add(len(h.cacheInvalidations))
for _, invalidate := range h.cacheInvalidations {
go func(invalidate func(context.Context, []*eventstore.Aggregate)) {
defer wg.Done()
invalidate(ctx, aggregates)
}(invalidate)
}
wg.Wait()
}
// aggregatesFromStatements returns the unique aggregates from statements.
// Duplicate aggregates are omitted.
func aggregatesFromStatements(statements []*Statement) []*eventstore.Aggregate {
aggregates := make([]*eventstore.Aggregate, 0, len(statements))
for _, statement := range statements {
if !slices.ContainsFunc(aggregates, func(aggregate *eventstore.Aggregate) bool {
return *statement.Aggregate == *aggregate
}) {
aggregates = append(aggregates, statement.Aggregate)
}
}
return aggregates
}