indexer: backups are now a deterministic set of SQL statements #1338
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,6 +1,7 @@ | ||
| package indexer | ||
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| import ( | ||
| "bufio" | ||
| "bytes" | ||
| "context" | ||
| "database/sql" | ||
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@@ -18,6 +19,7 @@ | |
| "sync" | ||
| "time" | ||
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| "go.vocdoni.io/dvote/data/compressor" | ||
| "go.vocdoni.io/dvote/log" | ||
| "go.vocdoni.io/dvote/statedb" | ||
| "go.vocdoni.io/dvote/types" | ||
|
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@@ -31,10 +33,11 @@ | |
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| "github.com/pressly/goose/v3" | ||
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| "github.com/schollz/sqlite3dump" | ||
| // modernc is a pure-Go version, but its errors have less useful info. | ||
| // We use mattn while developing and testing, and we can swap them later. | ||
| // _ "modernc.org/sqlite" | ||
| _ "github.com/mattn/go-sqlite3" | ||
| ) | ||
|
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| //go:generate go run github.com/sqlc-dev/sqlc/cmd/[email protected] generate | ||
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@@ -240,7 +243,8 @@ | |
| return nil | ||
| } | ||
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| // RestoreBackup restores the indexer by copying the file (raw binary format) | ||
| // from the passed path. | ||
| // Note that this must be called with ExpectBackupRestore set to true, | ||
| // and before any indexing or queries happen. | ||
| func (idx *Indexer) RestoreBackup(path string) error { | ||
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@@ -277,36 +281,111 @@ | |
| return len(migrations) > 0 | ||
| } | ||
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| // ImportBackup restores the database from a backup created via ExportBackup. | ||
| // Note that this must be called with ExpectBackupRestore set to true, | ||
| // and before any indexing or queries happen. | ||
| func (idx *Indexer) ImportBackup(r io.Reader) error { | ||
| if idx.readWriteDB != nil { | ||
| panic("Indexer.RestoreBackup called after the database was initialized") | ||
| } | ||
| log.Debugf("restoring indexer backup") | ||
|
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||
| zr, err := compressor.NewReader(r) | ||
| if err != nil { | ||
| return fmt.Errorf("could not init decompressor: %w", err) | ||
| } | ||
| defer zr.Close() | ||
|
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| if err := restoreDBFromSQLDump(idx.dbPath, zr); err != nil { | ||
| return fmt.Errorf("could not restore indexer backup: %w", err) | ||
| } | ||
| if err := idx.startDB(); err != nil { | ||
| return err | ||
| } | ||
| return nil | ||
| } | ||
|
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| func restoreDBFromSQLDump(dbPath string, r io.Reader) error { | ||
| db, err := sql.Open("sqlite3", fmt.Sprintf("file:%s?mode=rwc&_journal_mode=wal&_txlock=immediate&_synchronous=normal&_foreign_keys=true", dbPath)) | ||
| if err != nil { | ||
| return fmt.Errorf("could not open indexer db: %w", err) | ||
| } | ||
| defer db.Close() | ||
|
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||
| scanner := bufio.NewScanner(r) | ||
| var statement strings.Builder | ||
| for scanner.Scan() { | ||
| line := scanner.Text() | ||
| statement.WriteString(line) | ||
| statement.WriteString("\n") | ||
|
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| if strings.HasSuffix(line, ";") { | ||
| _, err := db.Exec(statement.String()) | ||
| if err != nil { | ||
| return fmt.Errorf("failed to execute statement: %s (error: %w)", statement.String(), err) | ||
| } | ||
| statement.Reset() | ||
| } | ||
| } | ||
|
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||
| if err := scanner.Err(); err != nil { | ||
| return fmt.Errorf("error during restore: %w", err) | ||
| } | ||
|
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| return nil | ||
| } | ||
|
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| // ExportBackup exports a (compressed) deterministic set of SQL statements. | ||
| // Note that writes to the database may be blocked until the method finishes. | ||
| func (idx *Indexer) ExportBackup(w io.Writer) error { | ||
| log.Debugf("exporting indexer backup") | ||
| ctx, cancel := context.WithTimeout(context.Background(), time.Minute) | ||
| defer cancel() | ||
|
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||
| tmpDB, err := os.CreateTemp("", "indexer*.sqlite3") | ||
| if err != nil { | ||
| return fmt.Errorf("could not create tmpdb file: %w", err) | ||
| } | ||
| defer os.Remove(tmpDB.Name()) | ||
|
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||
| if _, err := idx.readOnlyDB.ExecContext(ctx, `VACUUM INTO ?`, tmpDB.Name()); err != nil { | ||
| return fmt.Errorf("could not vacuum into tmpdb: %w", err) | ||
| } | ||
|
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||
| db, err := sql.Open("sqlite3", tmpDB.Name()) | ||
| if err != nil { | ||
| return fmt.Errorf("could not open tmpDB: %w", err) | ||
| } | ||
| defer db.Close() | ||
|
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||
| // first drop stats table | ||
| if _, err := db.ExecContext(ctx, `DROP TABLE IF EXISTS sqlite_stat1;`); err != nil { | ||
| return fmt.Errorf("could not drop table sqlite_stat1: %w", err) | ||
| } | ||
|
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||
| // make goose_db_version table deterministic | ||
| if _, err := db.ExecContext(ctx, `UPDATE goose_db_version SET tstamp = '1970-01-01 00:00:00';`); err != nil { | ||
| return fmt.Errorf("could not update goose_db_version: %w", err) | ||
| } | ||
|
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||
| zw, err := compressor.NewWriter(w) | ||
| if err != nil { | ||
| return fmt.Errorf("could not init compressor: %w", err) | ||
| } | ||
| defer zw.Close() | ||
|
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||
| return sqlite3dump.DumpDB(db, zw) | ||
| } | ||
|
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| // ExportBackupAsBytes backs up the database, and returns the contents as []byte. | ||
| // | ||
| // Note that writes to the database may be blocked until the backup finishes. | ||
| func (idx *Indexer) ExportBackupAsBytes(ctx context.Context) ([]byte, error) { | ||
| var buf bytes.Buffer | ||
| if err := idx.ExportBackup(&buf); err != nil { | ||
| return nil, fmt.Errorf("error saving indexer backup: %w", err) | ||
| } | ||
| return buf.Bytes(), nil | ||
| } | ||
|
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| // blockTxQueries assumes that lockPool is locked. | ||
|
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||
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are you sure that the entire text ends with
;? what if it's likein that case you would ignore
baz, so perhaps add a sanity check at the end that there's no remaining statement.