forked from
willdot.net/cocoon
A fork of the Cocoon PDS but being made more distributed.
event persisting using retryable sequencing increments on conflicts
Signed-off-by: Will <did:plc:dadhhalkfcq3gucaq25hjqon>
author
![]()
willdot.net
committer
Tangled
date
(Jun 6, 2026, 2:41 PM UTC)
commit
cd251b6b
cd251b6be6202426a2be24f01ddf9fc0409127c4
parent
20ed5d21
20ed5d210c5f55fbdef68a9b759ecd203c020689
change-id
nzlnlqmu
nzlnlqmursppvrkyoqzqyxyyolvylsts
+68
-55
+1
go.mod
+1
go.mod
+2
go.sum
+2
go.sum
···
9
9
github.com/alexbrainman/goissue34681 v0.0.0-20191006012335-3fc7a47baff5/go.mod h1:Y2QMoi1vgtOIfc+6DhrMOGkLoGzqSV2rKp4Sm+opsyA=
10
10
github.com/antlr4-go/antlr/v4 v4.13.0 h1:lxCg3LAv+EUK6t1i0y1V6/SLeUi0eKEKdhQAlS8TVTI=
11
11
github.com/antlr4-go/antlr/v4 v4.13.0/go.mod h1:pfChB/xh/Unjila75QW7+VU4TSnWnnk9UTnmpPaOR2g=
12
+
github.com/avast/retry-go/v4 v4.7.0 h1:yjDs35SlGvKwRNSykujfjdMxMhMQQM0TnIjJaHB+Zio=
13
+
github.com/avast/retry-go/v4 v4.7.0/go.mod h1:ZMPDa3sY2bKgpLtap9JRUgk2yTAba7cgiFhqxY2Sg6Q=
12
14
github.com/aws/aws-sdk-go v1.55.7 h1:UJrkFq7es5CShfBwlWAC8DA077vp8PyVbQd3lqLiztE=
13
15
github.com/aws/aws-sdk-go v1.55.7/go.mod h1:eRwEWoyTWFMVYVQzKMNHWP5/RV4xIUGMQfXQHfHkpNU=
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github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
+59
-52
server/persist.go
+59
-52
server/persist.go
···
3
3
import (
4
4
"bytes"
5
5
"context"
6
+
"errors"
6
7
"fmt"
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+
"log/slog"
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9
"sync"
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"time"
9
11
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+
"github.com/avast/retry-go/v4"
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"github.com/bluesky-social/indigo/api/atproto"
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"github.com/bluesky-social/indigo/events"
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indigomodels "github.com/bluesky-social/indigo/models"
···
19
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type DbPersister struct {
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Db *gorm.DB
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-
Lk sync.Mutex
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-
Seq int64
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+
Lk sync.Mutex
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Broadcast func(*events.XRPCStreamEvent)
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···
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Retention: retention,
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}
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46
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-
// kind of hacky. we will try and get the latest one from the db, but if it doesn't exist...well we have a problem
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// because the relay will already have _some_ value > 0 set as a cursor, we'll want to just set this to some high value
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// we'll just grab a current unix timestamp and set that as the cursor
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var lastEvent models.EventRecord
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if err := db.Order("seq desc").Limit(1).First(&lastEvent).Error; err != nil {
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if err != gorm.ErrRecordNotFound {
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return nil, fmt.Errorf("failed to get last event seq: %w", err)
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-
}
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p.Seq = time.Now().Unix()
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-
} else {
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-
p.Seq = lastEvent.Seq
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-
}
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-
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go p.cleanupRoutine()
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return p, nil
···
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p.Lk.Lock()
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defer p.Lk.Unlock()
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p.Seq++
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seq := p.Seq
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rec := &models.EventRecord{}
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if err := p.Db.Order("seq desc").Limit(1).First(rec).Error; err != nil {
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slog.Error("fetching most recent event record", "error", err)
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rec.Seq = time.Now().Unix()
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+
}
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+
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// if the error on inserting the event record is a constraint error, it means that
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// another event has been stored since getting the last sequence number. In that case
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// retry which will increase the sequence number again and hopefully work. Any others
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// can error out.
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retryIfFunc := func(err error) bool {
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return errors.Is(err, gorm.ErrDuplicatedKey)
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}
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err := retry.Do(func() error {
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rec.Seq++
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+
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var did string
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var evtType string
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+
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switch {
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case e.RepoCommit != nil:
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e.RepoCommit.Seq = rec.Seq
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did = e.RepoCommit.Repo
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evtType = "commit"
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+
case e.RepoSync != nil:
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+
e.RepoSync.Seq = rec.Seq
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+
did = e.RepoSync.Did
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evtType = "sync"
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case e.RepoIdentity != nil:
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e.RepoIdentity.Seq = rec.Seq
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did = e.RepoIdentity.Did
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evtType = "identity"
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case e.RepoAccount != nil:
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e.RepoAccount.Seq = rec.Seq
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did = e.RepoAccount.Did
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evtType = "account"
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default:
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+
return fmt.Errorf("unknown event type")
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+
}
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-
var did string
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var evtType string
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data, err := serializeEvent(e)
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+
if err != nil {
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+
return fmt.Errorf("failed to serialize event: %w", err)
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+
}
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104
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-
switch {
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-
case e.RepoCommit != nil:
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e.RepoCommit.Seq = seq
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did = e.RepoCommit.Repo
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-
evtType = "commit"
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case e.RepoSync != nil:
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e.RepoSync.Seq = seq
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did = e.RepoSync.Did
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evtType = "sync"
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case e.RepoIdentity != nil:
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-
e.RepoIdentity.Seq = seq
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did = e.RepoIdentity.Did
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-
evtType = "identity"
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-
case e.RepoAccount != nil:
91
-
e.RepoAccount.Seq = seq
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did = e.RepoAccount.Did
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evtType = "account"
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-
default:
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return fmt.Errorf("unknown event type")
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-
}
105
+
rec.CreatedAt = time.Now()
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+
rec.Did = did
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+
rec.Type = evtType
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+
rec.Data = data
97
109
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-
data, err := serializeEvent(e)
99
-
if err != nil {
100
-
return fmt.Errorf("failed to serialize event: %w", err)
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-
}
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+
err = p.Db.Create(rec).Error
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+
if err != nil {
112
+
return fmt.Errorf("failed to persist event: %w", err)
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+
}
102
114
103
-
rec := &models.EventRecord{
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-
Seq: seq,
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-
CreatedAt: time.Now(),
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-
Did: did,
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-
Type: evtType,
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-
Data: data,
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-
}
115
+
return nil
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+
}, retry.RetryIf(retryIfFunc))
110
117
111
-
if err := p.Db.Create(rec).Error; err != nil {
112
-
return fmt.Errorf("failed to persist event: %w", err)
118
+
if err != nil {
119
+
return err
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}
114
121
115
122
if p.Broadcast != nil {
+6
-3
server/server.go
+6
-3
server/server.go
···
348
348
}
349
349
350
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var gdb *gorm.DB
351
+
gormCfg := gorm.Config{
352
+
TranslateError: true,
353
+
}
351
354
var err error
352
355
switch dbType {
353
356
case "postgres":
354
357
if args.DatabaseURL == "" {
355
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return nil, fmt.Errorf("database-url must be set when using postgres")
356
359
}
357
-
gdb, err = gorm.Open(postgres.Open(args.DatabaseURL), &gorm.Config{})
360
+
gdb, err = gorm.Open(postgres.Open(args.DatabaseURL), &gormCfg)
358
361
if err != nil {
359
362
return nil, fmt.Errorf("failed to connect to postgres: %w", err)
360
363
}
···
366
369
db, err := sql.Open("libsql", fmt.Sprintf("%s?authToken=%s", primaryUrl, authToken))
367
370
gdb, err = gorm.Open(sqlite.New(sqlite.Config{
368
371
Conn: db,
369
-
}), &gorm.Config{})
372
+
}), &gormCfg)
370
373
if err != nil {
371
374
return nil, fmt.Errorf("failed to connect to postgres: %w", err)
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}
373
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logger.Info("connected to PostgreSQL database")
374
377
375
378
default:
376
-
gdb, err = gorm.Open(sqlite.Open(args.DbName), &gorm.Config{})
379
+
gdb, err = gorm.Open(sqlite.Open(args.DbName), &gormCfg)
377
380
if err != nil {
378
381
return nil, fmt.Errorf("failed to open sqlite database: %w", err)
379
382
}