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>
willdot.net
(Jun 6, 2026, 3:37 PM +0100)
cff1285e
20ed5d21
+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=
14
16
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"
8
+
"log/slog"
7
9
"sync"
8
10
"time"
9
11
12
+
"github.com/avast/retry-go/v4"
10
13
"github.com/bluesky-social/indigo/api/atproto"
11
14
"github.com/bluesky-social/indigo/events"
12
15
indigomodels "github.com/bluesky-social/indigo/models"
···
19
22
type DbPersister struct {
20
23
Db *gorm.DB
21
24
22
-
Lk sync.Mutex
23
-
Seq int64
25
+
Lk sync.Mutex
24
26
25
27
Broadcast func(*events.XRPCStreamEvent)
26
28
···
42
44
Retention: retention,
43
45
}
44
46
45
-
// 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
46
-
// because the relay will already have _some_ value > 0 set as a cursor, we'll want to just set this to some high value
47
-
// we'll just grab a current unix timestamp and set that as the cursor
48
-
var lastEvent models.EventRecord
49
-
if err := db.Order("seq desc").Limit(1).First(&lastEvent).Error; err != nil {
50
-
if err != gorm.ErrRecordNotFound {
51
-
return nil, fmt.Errorf("failed to get last event seq: %w", err)
52
-
}
53
-
p.Seq = time.Now().Unix()
54
-
} else {
55
-
p.Seq = lastEvent.Seq
56
-
}
57
-
58
47
go p.cleanupRoutine()
59
48
60
49
return p, nil
···
68
57
p.Lk.Lock()
69
58
defer p.Lk.Unlock()
70
59
71
-
p.Seq++
72
-
seq := p.Seq
60
+
rec := &models.EventRecord{}
61
+
if err := p.Db.Order("seq desc").Limit(1).First(rec).Error; err != nil {
62
+
slog.Error("fetching most recent event record", "error", err)
63
+
rec.Seq = time.Now().Unix()
64
+
}
65
+
66
+
// if the error on inserting the event record is a constraint error, it means that
67
+
// another event has been stored since getting the last sequence number. In that case
68
+
// retry which will increase the sequence number again and hopefully work. Any others
69
+
// can error out.
70
+
retryIfFunc := func(err error) bool {
71
+
return errors.Is(err, gorm.ErrDuplicatedKey)
72
+
}
73
+
err := retry.Do(func() error {
74
+
rec.Seq++
75
+
76
+
var did string
77
+
var evtType string
78
+
79
+
switch {
80
+
case e.RepoCommit != nil:
81
+
e.RepoCommit.Seq = rec.Seq
82
+
did = e.RepoCommit.Repo
83
+
evtType = "commit"
84
+
case e.RepoSync != nil:
85
+
e.RepoSync.Seq = rec.Seq
86
+
did = e.RepoSync.Did
87
+
evtType = "sync"
88
+
case e.RepoIdentity != nil:
89
+
e.RepoIdentity.Seq = rec.Seq
90
+
did = e.RepoIdentity.Did
91
+
evtType = "identity"
92
+
case e.RepoAccount != nil:
93
+
e.RepoAccount.Seq = rec.Seq
94
+
did = e.RepoAccount.Did
95
+
evtType = "account"
96
+
default:
97
+
return fmt.Errorf("unknown event type")
98
+
}
73
99
74
-
var did string
75
-
var evtType string
100
+
data, err := serializeEvent(e)
101
+
if err != nil {
102
+
return fmt.Errorf("failed to serialize event: %w", err)
103
+
}
76
104
77
-
switch {
78
-
case e.RepoCommit != nil:
79
-
e.RepoCommit.Seq = seq
80
-
did = e.RepoCommit.Repo
81
-
evtType = "commit"
82
-
case e.RepoSync != nil:
83
-
e.RepoSync.Seq = seq
84
-
did = e.RepoSync.Did
85
-
evtType = "sync"
86
-
case e.RepoIdentity != nil:
87
-
e.RepoIdentity.Seq = seq
88
-
did = e.RepoIdentity.Did
89
-
evtType = "identity"
90
-
case e.RepoAccount != nil:
91
-
e.RepoAccount.Seq = seq
92
-
did = e.RepoAccount.Did
93
-
evtType = "account"
94
-
default:
95
-
return fmt.Errorf("unknown event type")
96
-
}
105
+
rec.CreatedAt = time.Now()
106
+
rec.Did = did
107
+
rec.Type = evtType
108
+
rec.Data = data
97
109
98
-
data, err := serializeEvent(e)
99
-
if err != nil {
100
-
return fmt.Errorf("failed to serialize event: %w", err)
101
-
}
110
+
err = p.Db.Create(rec).Error
111
+
if err != nil {
112
+
return fmt.Errorf("failed to persist event: %w", err)
113
+
}
102
114
103
-
rec := &models.EventRecord{
104
-
Seq: seq,
105
-
CreatedAt: time.Now(),
106
-
Did: did,
107
-
Type: evtType,
108
-
Data: data,
109
-
}
115
+
return nil
116
+
}, 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
113
120
}
114
121
115
122
if p.Broadcast != nil {
+6
-3
server/server.go
+6
-3
server/server.go
···
348
348
}
349
349
350
350
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
358
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)
372
375
}
373
376
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
}