storj/satellite/metainfo/loop.go

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// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.
package metainfo
import (
"context"
"fmt"
"time"
"github.com/spacemonkeygo/monkit/v3"
"github.com/zeebo/errs"
"golang.org/x/time/rate"
"storj.io/common/storj"
"storj.io/common/uuid"
"storj.io/storj/satellite/metainfo/metabase"
)
var (
// LoopError is a standard error class for this component.
LoopError = errs.Class("metainfo loop error")
// LoopClosedError is a loop closed error.
LoopClosedError = LoopError.New("loop closed")
)
// Object is the object info passed to Observer by metainfo loop.
type Object struct {
Location metabase.ObjectLocation // tally
StreamID uuid.UUID // metrics, repair
SegmentCount int // metrics
MetadataSize int // tally
expirationDate time.Time // tally
}
// Expired checks if object is expired relative to now.
func (object *Object) Expired(now time.Time) bool {
return !object.expirationDate.IsZero() && object.expirationDate.Before(now)
}
// Segment is the segment info passed to Observer by metainfo loop.
type Segment struct {
Location metabase.SegmentLocation // tally, repair, graceful exit, audit
StreamID uuid.UUID // audit
DataSize int // tally, graceful exit
Inline bool // metrics
Redundancy storj.RedundancyScheme // tally, graceful exit, repair
RootPieceID storj.PieceID // gc, graceful exit
Pieces metabase.Pieces // tally, audit, gc, graceful exit, repair
CreationDate time.Time // repair
ExpirationDate time.Time // tally, repair
LastRepaired time.Time // repair
}
// Expired checks if segment is expired relative to now.
func (segment *Segment) Expired(now time.Time) bool {
return !segment.ExpirationDate.IsZero() && segment.ExpirationDate.Before(now)
}
// Observer is an interface defining an observer that can subscribe to the metainfo loop.
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//
// architecture: Observer
type Observer interface {
Object(context.Context, *Object) error
RemoteSegment(context.Context, *Segment) error
InlineSegment(context.Context, *Segment) error
}
// NullObserver is an observer that does nothing. This is useful for joining
// and ensuring the metainfo loop runs once before you use a real observer.
type NullObserver struct{}
// Object implements the Observer interface.
func (NullObserver) Object(context.Context, *Object) error {
return nil
}
// RemoteSegment implements the Observer interface.
func (NullObserver) RemoteSegment(context.Context, *Segment) error {
return nil
}
// InlineSegment implements the Observer interface.
func (NullObserver) InlineSegment(context.Context, *Segment) error {
return nil
}
type observerContext struct {
observer Observer
ctx context.Context
done chan error
object *monkit.DurationDist
remote *monkit.DurationDist
inline *monkit.DurationDist
}
func newObserverContext(ctx context.Context, obs Observer) *observerContext {
name := fmt.Sprintf("%T", obs)
key := monkit.NewSeriesKey("observer").WithTag("name", name)
return &observerContext{
observer: obs,
ctx: ctx,
done: make(chan error),
object: monkit.NewDurationDist(key.WithTag("pointer_type", "object")),
inline: monkit.NewDurationDist(key.WithTag("pointer_type", "inline")),
remote: monkit.NewDurationDist(key.WithTag("pointer_type", "remote")),
}
}
func (observer *observerContext) Object(ctx context.Context, object *Object) error {
start := time.Now()
defer func() { observer.object.Insert(time.Since(start)) }()
return observer.observer.Object(ctx, object)
}
func (observer *observerContext) RemoteSegment(ctx context.Context, segment *Segment) error {
start := time.Now()
defer func() { observer.remote.Insert(time.Since(start)) }()
return observer.observer.RemoteSegment(ctx, segment)
}
func (observer *observerContext) InlineSegment(ctx context.Context, segment *Segment) error {
start := time.Now()
defer func() { observer.inline.Insert(time.Since(start)) }()
return observer.observer.InlineSegment(ctx, segment)
}
func (observer *observerContext) HandleError(err error) bool {
if err != nil {
observer.done <- err
observer.Finish()
return true
}
return false
}
func (observer *observerContext) Finish() {
close(observer.done)
name := fmt.Sprintf("%T", observer.observer)
stats := allObserverStatsCollectors.GetStats(name)
stats.Observe(observer)
}
func (observer *observerContext) Wait() error {
return <-observer.done
}
// LoopConfig contains configurable values for the metainfo loop.
type LoopConfig struct {
CoalesceDuration time.Duration `help:"how long to wait for new observers before starting iteration" releaseDefault:"5s" devDefault:"5s"`
RateLimit float64 `help:"rate limit (default is 0 which is unlimited segments per second)" default:"0"`
ListLimit int `help:"how many items to query in a batch" default:"2500"`
}
// Loop is a metainfo loop service.
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//
// architecture: Service
type Loop struct {
config LoopConfig
db PointerDB
bucketsDB BucketsDB
metabaseDB MetabaseDB
join chan []*observerContext
done chan struct{}
}
// NewLoop creates a new metainfo loop service.
func NewLoop(config LoopConfig, db PointerDB, bucketsDB BucketsDB, metabaseDB MetabaseDB) *Loop {
return &Loop{
db: db,
bucketsDB: bucketsDB,
metabaseDB: metabaseDB,
config: config,
join: make(chan []*observerContext),
done: make(chan struct{}),
}
}
// Join will join the looper for one full cycle until completion and then returns.
// On ctx cancel the observer will return without completely finishing.
// Only on full complete iteration it will return nil.
// Safe to be called concurrently.
func (loop *Loop) Join(ctx context.Context, observers ...Observer) (err error) {
defer mon.Task()(&ctx)(&err)
obsContexts := make([]*observerContext, len(observers))
for i, obs := range observers {
obsContexts[i] = newObserverContext(ctx, obs)
}
select {
case loop.join <- obsContexts:
case <-ctx.Done():
return ctx.Err()
case <-loop.done:
return LoopClosedError
}
var errList errs.Group
for _, ctx := range obsContexts {
errList.Add(ctx.Wait())
}
return errList.Err()
}
// Run starts the looping service.
// It can only be called once, otherwise a panic will occur.
func (loop *Loop) Run(ctx context.Context) (err error) {
defer mon.Task()(&ctx)(&err)
for {
err := loop.runOnce(ctx)
if err != nil {
return err
}
}
}
// Close closes the looping services.
func (loop *Loop) Close() (err error) {
close(loop.done)
return nil
}
// runOnce goes through metainfo one time and sends information to observers.
func (loop *Loop) runOnce(ctx context.Context) (err error) {
defer mon.Task()(&ctx)(&err)
var observers []*observerContext
// wait for the first observer, or exit because context is canceled
select {
case list := <-loop.join:
observers = append(observers, list...)
case <-ctx.Done():
return ctx.Err()
}
// after the first observer is found, set timer for CoalesceDuration and add any observers that try to join before the timer is up
timer := time.NewTimer(loop.config.CoalesceDuration)
waitformore:
for {
select {
case list := <-loop.join:
observers = append(observers, list...)
case <-timer.C:
break waitformore
case <-ctx.Done():
finishObservers(observers)
return ctx.Err()
}
}
return iterateDatabase(ctx, loop.db, loop.bucketsDB, loop.metabaseDB, observers, loop.config.ListLimit, rate.NewLimiter(rate.Limit(loop.config.RateLimit), 1))
}
// IterateDatabase iterates over PointerDB and notifies specified observers about results.
//
// It uses 10000 as the lookup limit for iterating.
func IterateDatabase(ctx context.Context, rateLimit float64, db PointerDB, bucketsDB BucketsDB, metabaseDB MetabaseDB, observers ...Observer) error {
obsContexts := make([]*observerContext, len(observers))
for i, observer := range observers {
obsContexts[i] = newObserverContext(ctx, observer)
}
return iterateDatabase(ctx, db, bucketsDB, metabaseDB, obsContexts, 10000, rate.NewLimiter(rate.Limit(rateLimit), 1))
}
// Wait waits for run to be finished.
// Safe to be called concurrently.
func (loop *Loop) Wait() {
<-loop.done
}
func iterateDatabase(ctx context.Context, db PointerDB, bucketsDB BucketsDB, metabaseDB MetabaseDB, observers []*observerContext, limit int, rateLimiter *rate.Limiter) (err error) {
defer func() {
if err != nil {
for _, observer := range observers {
observer.HandleError(err)
}
return
}
finishObservers(observers)
}()
observers, err = iterateObjects(ctx, metabaseDB, observers, limit, rateLimiter)
if err != nil {
return LoopError.Wrap(err)
}
return err
}
func iterateObjects(ctx context.Context, metabaseDB MetabaseDB, observers []*observerContext, limit int, rateLimiter *rate.Limiter) (_ []*observerContext, err error) {
defer mon.Task()(&ctx)(&err)
// TODO we should improve performance here, this is just most straightforward solution
err = metabaseDB.FullIterateObjects(ctx, metabase.FullIterateObjects{
BatchSize: limit,
}, func(ctx context.Context, it metabase.FullObjectsIterator) error {
var entry metabase.FullObjectEntry
for it.Next(ctx, &entry) {
if err := rateLimiter.Wait(ctx); err != nil {
// We don't really execute concurrent batches so we should never
// exceed the burst size of 1 and this should never happen.
// We can also enter here if the context is cancelled.
return err
}
nextObservers := observers[:0]
for _, observer := range observers {
keepObserver := handleObject(ctx, observer, entry)
if keepObserver {
nextObservers = append(nextObservers, observer)
}
}
observers = nextObservers
if len(observers) == 0 {
return nil
}
// if context has been canceled exit. Otherwise, continue
if err := ctx.Err(); err != nil {
return err
}
more := true
cursor := metabase.SegmentPosition{}
for more {
if err := rateLimiter.Wait(ctx); err != nil {
// We don't really execute concurrent batches so we should never
// exceed the burst size of 1 and this should never happen.
// We can also enter here if the context is cancelled.
return err
}
segments, err := metabaseDB.ListSegments(ctx, metabase.ListSegments{
StreamID: entry.StreamID,
Cursor: cursor,
Limit: limit,
})
if err != nil {
return err
}
for _, segment := range segments.Segments {
nextObservers := observers[:0]
location := metabase.SegmentLocation{
ProjectID: entry.ProjectID,
BucketName: entry.BucketName,
ObjectKey: entry.ObjectKey,
Position: segment.Position,
}
for _, observer := range observers {
keepObserver := handleSegment(ctx, observer, location, segment, entry.ExpiresAt)
if keepObserver {
nextObservers = append(nextObservers, observer)
}
}
observers = nextObservers
if len(observers) == 0 {
return nil
}
// if context has been canceled exit. Otherwise, continue
if err := ctx.Err(); err != nil {
return err
}
}
more = segments.More
if more {
lastSegment := segments.Segments[len(segments.Segments)-1]
cursor = lastSegment.Position
}
}
}
return nil
})
return observers, err
}
func handleObject(ctx context.Context, observer *observerContext, object metabase.FullObjectEntry) bool {
expirationDate := time.Time{}
if object.ExpiresAt != nil {
expirationDate = *object.ExpiresAt
}
if observer.HandleError(observer.Object(ctx, &Object{
Location: object.Location(),
StreamID: object.StreamID,
SegmentCount: int(object.SegmentCount),
MetadataSize: len(object.EncryptedMetadata),
expirationDate: expirationDate,
})) {
return false
}
select {
case <-observer.ctx.Done():
observer.HandleError(observer.ctx.Err())
return false
default:
}
return true
}
func handleSegment(ctx context.Context, observer *observerContext, location metabase.SegmentLocation, segment metabase.Segment, expiresAt *time.Time) bool {
loopSegment := &Segment{
Location: location,
}
if expiresAt != nil {
loopSegment.ExpirationDate = *expiresAt
}
loopSegment.StreamID = segment.StreamID
loopSegment.DataSize = int(segment.EncryptedSize)
if segment.Inline() {
loopSegment.Inline = true
if observer.HandleError(observer.InlineSegment(ctx, loopSegment)) {
return false
}
} else {
loopSegment.RootPieceID = segment.RootPieceID
loopSegment.Redundancy = segment.Redundancy
loopSegment.Pieces = segment.Pieces
if observer.HandleError(observer.RemoteSegment(ctx, loopSegment)) {
return false
}
}
select {
case <-observer.ctx.Done():
observer.HandleError(observer.ctx.Err())
return false
default:
}
return true
}
func finishObservers(observers []*observerContext) {
for _, observer := range observers {
observer.Finish()
}
}