An implementation of the ATProto statusphere example app but in Go
track the jetstream cursor
Signed-off-by: Will Andrews <did:plc:dadhhalkfcq3gucaq25hjqon>
authored by
+79
-1
+16
-1
consumer.go
+16
-1
consumer.go
···
47
47
return fmt.Errorf("failed to create client: %w", err)
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}
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49
50
-
cursor := time.Now().Add(1 * -time.Minute).UnixMicro()
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+
cursor, err := c.handler.store.GetCursor(ctx)
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+
// if cursor can't be fetched, just start from a couple days ago.
52
+
if err != nil || cursor == 0 {
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+
cursor = time.Now().Add(-time.Hour * 48).UnixMicro()
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+
}
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+
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+
slog.Info("starting from cursor", "time", time.UnixMicro(cursor), "cursor", cursor)
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57
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if err := client.ConnectAndRead(ctx, &cursor); err != nil {
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return fmt.Errorf("connect and read: %w", err)
···
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65
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type HandlerStore interface {
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CreateStatus(status Status) error
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+
SaveCursor(ctx context.Context, cursor int64) error
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+
GetCursor(ctx context.Context) (int64, error)
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}
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type handler struct {
···
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77
if event.Commit == nil {
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return nil
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}
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+
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+
defer func() {
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+
err := h.store.SaveCursor(ctx, event.TimeUS)
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+
if err != nil {
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+
slog.Error("failed to save cursor", "error", err)
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+
}
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+
}()
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switch event.Commit.Operation {
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case models.CommitOperationCreate:
+5
database/database.go
+5
database/database.go
+58
database/jetstream_cursor.go
+58
database/jetstream_cursor.go
···
1
+
package database
2
+
3
+
import (
4
+
"context"
5
+
"database/sql"
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+
"fmt"
7
+
"log/slog"
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+
)
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+
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+
func createJetstreamTable(db *sql.DB) error {
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createJetstreamTableSQL := `CREATE TABLE IF NOT EXISTS jetstream (
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+
"id" integer NOT NULL PRIMARY KEY,
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"cursor" INTEGER,
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UNIQUE(id)
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+
);`
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+
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slog.Info("Create jetstream table...")
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statement, err := db.Prepare(createJetstreamTableSQL)
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+
if err != nil {
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return fmt.Errorf("prepare DB statement to create jetstream table: %w", err)
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+
}
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_, err = statement.Exec()
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+
if err != nil {
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+
return fmt.Errorf("exec sql statement to create jetstream table: %w", err)
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+
}
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slog.Info("jetstream table created")
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+
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return nil
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+
}
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+
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func (d *DB) SaveCursor(ctx context.Context, cursor int64) error {
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sql := `INSERT INTO jetstream (id, cursor) VALUES (1, ?) ON CONFLICT(id) DO UPDATE SET cursor = ?;`
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_, err := d.db.Exec(sql, cursor, cursor)
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+
if err != nil {
35
+
return fmt.Errorf("exec insert or update cursor: %w", err)
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+
}
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+
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return nil
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+
}
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+
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func (d *DB) GetCursor(ctx context.Context) (int64, error) {
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+
sql := "SELECT cursor FROM jetstream where id = 1;"
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rows, err := d.db.Query(sql)
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+
if err != nil {
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+
return 0, fmt.Errorf("run query to get cursor: %w", err)
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+
}
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+
defer rows.Close()
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+
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+
cursor := 0
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+
for rows.Next() {
51
+
if err := rows.Scan(&cursor); err != nil {
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+
return 0, fmt.Errorf("scan row: %w", err)
53
+
}
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+
55
+
return int64(cursor), nil
56
+
}
57
+
return 0, fmt.Errorf("not found")
58
+
}