Files
litestream/wal_writer_test.go
Ben Johnson a090706421 Implement live read replication
This commit adds an http server and client for streaming snapshots
and WAL pages from an upstream Litestream primary to a read-only
replica.
2022-02-19 09:06:49 -07:00

117 lines
2.9 KiB
Go

package litestream_test
import (
"bytes"
"database/sql"
"encoding/binary"
"io"
"os"
"path/filepath"
"testing"
"github.com/benbjohnson/litestream"
"github.com/benbjohnson/litestream/internal/testingutil"
_ "github.com/mattn/go-sqlite3"
)
func TestWALWriter_Static(t *testing.T) {
testDir := filepath.Join("testdata", "wal-writer", "static")
tempDir := t.TempDir()
// Read in WAL file generated by sqlite3
buf, err := os.ReadFile(filepath.Join(testDir, "db-wal"))
if err != nil {
t.Fatal(err)
}
// Create new WAL file.
if err := os.WriteFile(filepath.Join(tempDir, "db-wal"), nil, 0666); err != nil {
t.Fatal(err)
}
w := litestream.NewWALWriter(filepath.Join(tempDir, "db-wal"), 0666, 4096)
w.Salt0 = binary.BigEndian.Uint32(buf[16:])
w.Salt1 = binary.BigEndian.Uint32(buf[20:])
if err := w.Open(); err != nil {
t.Fatal(err)
} else if err := w.WriteHeader(); err != nil {
t.Fatal(err)
}
for b := buf[litestream.WALHeaderSize:]; len(b) > 0; b = b[litestream.WALFrameHeaderSize+4096:] {
pgno := binary.BigEndian.Uint32(b[0:])
commit := binary.BigEndian.Uint32(b[4:])
if err := w.WriteFrame(pgno, commit, b[litestream.WALFrameHeaderSize:][:4096]); err != nil {
t.Fatal(err)
}
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
// Read generated WAL and compare with original.
if buf2, err := os.ReadFile(filepath.Join(tempDir, "db-wal")); err != nil {
t.Fatal(err)
} else if !bytes.Equal(buf, buf2) {
t.Fatal("wal file mismatch")
}
}
func TestWALWriter_Live(t *testing.T) {
testDir := filepath.Join("testdata", "wal-writer", "live")
tempDir := t.TempDir()
// Copy DB file into temporary dir.
testingutil.CopyFile(t, filepath.Join(testDir, "db"), filepath.Join(tempDir, "db"))
// Open database.
db, err := sql.Open("sqlite3", filepath.Join(tempDir, "db"))
if err != nil {
t.Fatal(err)
}
defer db.Close()
// Verify that table is empty.
var n int
if err := db.QueryRow(`SELECT COUNT(*) FROM t`).Scan(&n); err != nil {
t.Fatal(err)
} else if got, want := n, 0; got != want {
t.Fatalf("init: n=%d, want %d", got, want)
}
// Copy WAL file into place.
testingutil.CopyFile(t, filepath.Join(testDir, "db-wal"), filepath.Join(tempDir, "db-wal"))
// Invalidate both copies of the WAL index headers.
f, err := os.OpenFile(filepath.Join(tempDir, "db-shm"), os.O_RDWR, 0666)
if err != nil {
t.Fatal(err)
}
defer f.Close()
// Read index header.
idx := make([]byte, 136)
if _, err := io.ReadFull(f, idx); err != nil {
t.Fatal(err)
}
// Invalidate "isInit" flags
idx[12], idx[48+12] = 0, 0
// Write header back into index.
if _, err := f.Seek(0, io.SeekStart); err != nil {
t.Fatal(err)
} else if _, err := f.Write(idx); err != nil {
t.Fatal(err)
}
// Verify that table now has one row.
if err := db.QueryRow(`SELECT COUNT(*) FROM t`).Scan(&n); err != nil {
t.Fatal(err)
} else if got, want := n, 1; got != want {
t.Fatalf("post-wal: n=%d, want %d", got, want)
}
}