Files
go-cart-actor/pkg/actor/disk_storage.go
T
mats 2e2060da5c
Build and Publish / BuildAndDeployAmd64 (push) Failing after 3s
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metrics
2026-07-02 10:37:36 +02:00

497 lines
12 KiB
Go

package actor
import (
"context"
"errors"
"fmt"
"log"
"os"
"path/filepath"
"strings"
"sync"
"time"
"google.golang.org/protobuf/proto"
)
const defaultWriterIdleTTL = 5 * time.Minute
type QueueEvent struct {
TimeStamp time.Time
Message proto.Message
}
// diskLogWriter holds one append-only log file kept open between writes.
type diskLogWriter struct {
mu sync.Mutex
file *os.File
lastUsed time.Time
purged bool // set by purgeIdleWriters before closing; getWriter re-checks after acquiring mu
}
type DiskStorage[V any] struct {
*StateStorage
path string
done chan struct{}
queue *sync.Map // map[uint64][]QueueEvent
dirOnce sync.Once
dirErr error
writersMu sync.Mutex
writers map[uint64]*diskLogWriter
writerIdleTTL time.Duration
}
type LogStorage[V any] interface {
LoadEvents(ctx context.Context, id uint64, grain Grain[V]) error
LoadEventsFunc(ctx context.Context, id uint64, grain Grain[V], condition func(msg proto.Message, index int, timeStamp time.Time) bool) error
AppendMutations(id uint64, msg ...proto.Message) error
}
func NewDiskStorage[V any](path string, registry MutationRegistry) *DiskStorage[V] {
s := &DiskStorage[V]{
StateStorage: NewState(registry),
path: path,
done: make(chan struct{}),
writers: make(map[uint64]*diskLogWriter),
writerIdleTTL: defaultWriterIdleTTL,
}
go s.purgeLoop()
go s.filesExistingLoop()
return s
}
// filesExistingLoop refreshes the EventLogFilesExisting gauge every
// 30 seconds. The gauge represents the count of .events.log files on
// disk, which diverges from the open-writer count whenever the idle
// purge closes a writer but the file is still kept (the .log file is
// not deleted by the idle purge). Periodic re-listing is cheap (one
// os.ReadDir per tick) and is the only way the gauge can pick up files
// created or removed out of band (e.g. GDPR purge, or the init-time
// rebuild of a grain that already has a log).
func (s *DiskStorage[V]) filesExistingLoop() {
ticker := time.NewTicker(30 * time.Second)
defer ticker.Stop()
for {
select {
case <-s.done:
return
case <-ticker.C:
s.refreshFilesExisting()
}
}
}
// refreshFilesExisting counts .events.log files in the storage dir
// and writes the value to the EventLogFilesExisting gauge. Safe to
// call concurrently — os.ReadDir is atomic for our purposes (the dir
// is owned by this pod, mutations go through the writersMu lock).
// No-op when the dir does not exist yet (cold start) or when metrics
// are disabled (s.StateStorage.metrics == nil).
func (s *DiskStorage[V]) refreshFilesExisting() {
if s.StateStorage.metrics == nil {
return
}
entries, err := os.ReadDir(s.path)
if err != nil {
// Dir may not exist yet on a cold start, or briefly during a
// retention-driven directory recreation. Leave the gauge
// untouched in that case — the next tick will catch up.
return
}
count := 0
for _, e := range entries {
if !e.IsDir() && strings.HasSuffix(e.Name(), ".events.log") {
count++
}
}
s.StateStorage.metrics.EventLogFilesExisting.Set(float64(count))
}
func (s *DiskStorage[V]) ensureDir() error {
s.dirOnce.Do(func() {
s.dirErr = os.MkdirAll(s.path, 0o755)
})
return s.dirErr
}
// getWriter returns an open append handle for id. The caller must unlock w.mu
// when finished writing.
// SetMetrics attaches a Metrics instance to the embedded StateStorage
// so every append / replay / unknown-type path has access to the
// same event-log counters. The metrics struct is shared by reference;
// do not mutate its fields from outside. Pass nil to disable
// instrumentation (used by tests that do not care about Prometheus).
func (s *DiskStorage[V]) SetMetrics(m *Metrics) {
s.StateStorage.metrics = m
}
func (s *DiskStorage[V]) recordAppend(n int) {
m := s.StateStorage.metrics
if m == nil {
return
}
m.EventLogAppends.Inc()
if n > 0 {
m.EventLogBytesWritten.Add(float64(n))
}
m.EventLogLastAppendUnix.Set(float64(time.Now().Unix()))
}
func (s *DiskStorage[V]) writeEvents(id uint64, events []QueueEvent) error {
if len(events) == 0 {
return nil
}
w, err := s.getWriter(id)
if err != nil {
return err
}
defer w.mu.Unlock()
for _, evt := range events {
n, err := s.Append(w.file, evt.Message, evt.TimeStamp)
if err != nil {
// A partial write still counts the bytes that DID land on
// disk, so the throughput gauge is honest about a mid-write
// failure.
s.recordAppend(n)
return err
}
s.recordAppend(n)
}
w.lastUsed = time.Now()
return nil
}
func (s *DiskStorage[V]) writeMutations(id uint64, msgs ...proto.Message) error {
if len(msgs) == 0 {
return nil
}
w, err := s.getWriter(id)
if err != nil {
return err
}
defer w.mu.Unlock()
now := time.Now()
for _, m := range msgs {
n, err := s.Append(w.file, m, now)
if err != nil {
s.recordAppend(n)
return err
}
s.recordAppend(n)
}
w.lastUsed = time.Now()
return nil
}
func (s *DiskStorage[V]) purgeLoop() {
ticker := time.NewTicker(time.Minute)
defer ticker.Stop()
for {
select {
case <-s.done:
return
case <-ticker.C:
s.purgeIdleWriters()
}
}
}
func (s *DiskStorage[V]) purgeIdleWriters() {
cutoff := time.Now().Add(-s.writerIdleTTL)
s.writersMu.Lock()
defer s.writersMu.Unlock()
for id, w := range s.writers {
w.mu.Lock()
if w.lastUsed.Before(cutoff) {
w.purged = true
delete(s.writers, id)
if err := w.file.Close(); err != nil {
log.Printf("failed to close idle event log %d: %v", id, err)
}
}
w.mu.Unlock()
}
}
func (s *DiskStorage[V]) getWriter(id uint64) (*diskLogWriter, error) {
if err := s.ensureDir(); err != nil {
return nil, err
}
for {
s.writersMu.Lock()
w, ok := s.writers[id]
if !ok {
fh, err := os.OpenFile(s.logPath(id), os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
if err != nil {
s.writersMu.Unlock()
return nil, err
}
w = &diskLogWriter{file: fh, lastUsed: time.Now()}
s.writers[id] = w
}
s.writersMu.Unlock()
w.mu.Lock()
if !w.purged {
w.lastUsed = time.Now()
return w, nil
}
// Writer was purged by purgeIdleWriters between our map lookup and acquiring w.mu.
// Release it and retry — the map no longer contains this entry, so the next
// iteration will create a fresh writer.
w.mu.Unlock()
}
}
func (s *DiskStorage[V]) closeWriters() {
s.writersMu.Lock()
defer s.writersMu.Unlock()
for id, w := range s.writers {
w.mu.Lock()
w.purged = true
if err := w.file.Close(); err != nil {
log.Printf("failed to close event log %d: %v", id, err)
}
delete(s.writers, id)
w.mu.Unlock()
}
}
func (s *DiskStorage[V]) SaveLoop(duration time.Duration) {
s.queue = &sync.Map{}
ticker := time.NewTicker(duration)
defer ticker.Stop()
for {
select {
case <-s.done:
s.save()
return
case <-ticker.C:
s.save()
}
}
}
func (s *DiskStorage[V]) save() {
if s.queue == nil {
return
}
carts := 0
lines := 0
s.queue.Range(func(key, value any) bool {
id := key.(uint64)
qe, ok := value.([]QueueEvent)
if !ok {
s.queue.Delete(id)
return true
}
if err := s.writeEvents(id, qe); err != nil {
log.Printf("failed to append events for grain %d: %v", id, err)
return true
}
lines += len(qe)
carts++
s.queue.Delete(id)
return true
})
if lines > 0 {
log.Printf("Appended %d carts and %d lines to disk", carts, lines)
}
}
func (s *DiskStorage[V]) logPath(id uint64) string {
return filepath.Join(s.path, fmt.Sprintf("%d.events.log", id))
}
// loadReplayMetrics times the replay, records duration, and tracks
// handler errors. It is shared by LoadEvents and LoadEventsFunc. The
// returned `onMessage` closure bumps EventLogMutationErrors on any
// non-nil error from registry.Apply, and the deferred function bumps
// EventLogReplayTotal / Failures / Duration on the overall return.
func (s *DiskStorage[V]) loadReplayMetrics() (onMessage func(err error), done func(err error)) {
m := s.StateStorage.metrics
if m == nil {
noop := func(error) {}
return noop, noop
}
start := time.Now()
onMessage = func(err error) {
if err != nil {
m.EventLogMutationErrors.Inc()
}
}
done = func(err error) {
if err != nil {
m.EventLogReplayFailures.Inc()
return
}
m.EventLogReplayTotal.Inc()
m.EventLogReplayDuration.Observe(time.Since(start).Seconds())
}
return onMessage, done
}
// recordReplayFailure bumps EventLogReplayFailures when the open
// step fails before the Load loop runs (and therefore before the
// loadReplayMetrics closure is in scope). Nil-safe.
func (s *DiskStorage[V]) recordReplayFailure() {
if m := s.StateStorage.metrics; m != nil {
m.EventLogReplayFailures.Inc()
}
}
func (s *DiskStorage[V]) LoadEventsFunc(ctx context.Context, id uint64, grain Grain[V], condition func(msg proto.Message, index int, timeStamp time.Time) bool) error {
path := s.logPath(id)
if _, err := os.Stat(path); errors.Is(err, os.ErrNotExist) {
// No log -> nothing to replay
return nil
}
fh, err := os.Open(path)
if err != nil {
s.recordReplayFailure()
return fmt.Errorf("open replay file: %w", err)
}
defer fh.Close()
trackApply, done := s.loadReplayMetrics()
index := 0
loadErr := s.Load(fh, func(msg proto.Message, when time.Time) {
if condition(msg, index, when) {
results, _ := s.registry.Apply(ctx, grain, msg)
for _, r := range results {
if r.Error != nil {
trackApply(r.Error)
}
}
}
index++
})
done(loadErr)
return loadErr
}
func (s *DiskStorage[V]) LoadEvents(ctx context.Context, id uint64, grain Grain[V]) error {
path := s.logPath(id)
if _, err := os.Stat(path); errors.Is(err, os.ErrNotExist) {
// No log -> nothing to replay
return nil
}
fh, err := os.Open(path)
if err != nil {
s.recordReplayFailure()
return fmt.Errorf("open replay file: %w", err)
}
defer fh.Close()
trackApply, done := s.loadReplayMetrics()
loadErr := s.Load(fh, func(msg proto.Message, _ time.Time) {
results, _ := s.registry.Apply(ctx, grain, msg)
for _, r := range results {
if r.Error != nil {
trackApply(r.Error)
}
}
})
done(loadErr)
return loadErr
}
func (s *DiskStorage[V]) Close() {
if s.queue != nil {
s.save()
}
s.closeWriters()
close(s.done)
}
func (s *DiskStorage[V]) AppendMutations(id uint64, msg ...proto.Message) error {
if s.queue != nil {
queue := make([]QueueEvent, 0)
data, found := s.queue.Load(id)
if found {
queue = data.([]QueueEvent)
}
for _, m := range msg {
queue = append(queue, QueueEvent{Message: m, TimeStamp: time.Now()})
}
s.queue.Store(id, queue)
return nil
}
return s.writeMutations(id, msg...)
}
func (s *DiskStorage[V]) openWriterCount() int {
s.writersMu.Lock()
defer s.writersMu.Unlock()
return len(s.writers)
}
func (s *DiskStorage[V]) PurgeOlderThan(ctx context.Context, retention time.Duration, isGrainActive func(id uint64) bool) (int, error) {
if err := s.ensureDir(); err != nil {
return 0, err
}
files, err := os.ReadDir(s.path)
if err != nil {
return 0, fmt.Errorf("read storage dir: %w", err)
}
cutoff := time.Now().Add(-retention)
purgedCount := 0
for _, entry := range files {
if entry.IsDir() {
continue
}
name := entry.Name()
if !strings.HasSuffix(name, ".events.log") {
continue
}
var id uint64
_, err := fmt.Sscanf(name, "%d.events.log", &id)
if err != nil {
continue
}
info, err := entry.Info()
if err != nil {
log.Printf("failed to get file info for %s: %v", name, err)
continue
}
if info.ModTime().Before(cutoff) {
// Check if grain is active in memory
if isGrainActive != nil && isGrainActive(id) {
continue
}
// Check if we have an active writer open
s.writersMu.Lock()
_, hasWriter := s.writers[id]
s.writersMu.Unlock()
if hasWriter {
continue
}
// Delete the file
fullPath := filepath.Join(s.path, name)
if err := os.Remove(fullPath); err != nil {
log.Printf("failed to delete expired cart log %s: %v", fullPath, err)
} else {
purgedCount++
}
}
}
return purgedCount, nil
}