feat: Week 3 Phase 1 - WAL Archiving & PITR Setup
## WAL Archiving Implementation (Phase 1/5) ### Core Components Created - ✅ internal/wal/archiver.go (280 lines) - WAL file archiving with timeline/segment parsing - Archive statistics and cleanup - Compression/encryption scaffolding (TODO) - ✅ internal/wal/pitr_config.go (360 lines) - PostgreSQL configuration management - auto-detects postgresql.conf location - Backs up config before modifications - Recovery configuration for PG 12+ and legacy - ✅ cmd/pitr.go (350 lines) - pitr enable/disable/status commands - wal archive/list/cleanup commands - Integrated with existing CLI ### Features Implemented **WAL Archiving:** - ParseWALFileName: Extract timeline + segment from WAL files - ArchiveWALFile: Copy WAL to archive directory - ListArchivedWALFiles: View all archived WAL segments - CleanupOldWALFiles: Retention-based cleanup - GetArchiveStats: Statistics (total size, file count, date range) **PITR Configuration:** - EnablePITR: Auto-configure postgresql.conf for PITR - Sets wal_level=replica, archive_mode=on - Configures archive_command to call dbbackup - Creates WAL archive directory - DisablePITR: Turn off WAL archiving - GetCurrentPITRConfig: Read current settings - CreateRecoveryConf: Generate recovery config (PG 12+ & legacy) **CLI Commands:** ```bash # Enable PITR dbbackup pitr enable --archive-dir /backups/wal_archive # Check PITR status dbbackup pitr status # Archive WAL file (called by PostgreSQL) dbbackup wal archive <path> <filename> --archive-dir /backups/wal # List WAL archives dbbackup wal list --archive-dir /backups/wal_archive # Cleanup old WAL files dbbackup wal cleanup --archive-dir /backups/wal_archive --retention-days 7 ``` ### Architecture - Modular design: Separate archiver and PITR manager - PostgreSQL version detection (12+ vs legacy) - Automatic config file discovery - Safe config modifications with backups ### Next Steps (Phase 2) - [ ] Compression support (gzip) - [ ] Encryption support (AES-256-GCM) - [ ] Continuous WAL monitoring - [ ] Timeline management - [ ] Point-in-time restore command Time: ~1.5h (3h estimated for Phase 1)
This commit is contained in:
386
internal/wal/pitr_config.go
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386
internal/wal/pitr_config.go
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package wal
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import (
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"bufio"
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"context"
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"fmt"
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"os"
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"os/exec"
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"path/filepath"
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"regexp"
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"strings"
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"time"
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"dbbackup/internal/config"
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"dbbackup/internal/logger"
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)
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// PITRManager manages Point-in-Time Recovery configuration
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type PITRManager struct {
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cfg *config.Config
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log logger.Logger
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}
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// PITRConfig holds PITR settings
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type PITRConfig struct {
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Enabled bool
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ArchiveMode string // "on", "off", "always"
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ArchiveCommand string
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ArchiveDir string
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WALLevel string // "minimal", "replica", "logical"
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MaxWALSenders int
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WALKeepSize string // e.g., "1GB"
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RestoreCommand string
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}
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// RecoveryTarget specifies the point-in-time to recover to
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type RecoveryTarget struct {
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TargetTime *time.Time // Recover to specific timestamp
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TargetXID string // Recover to transaction ID
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TargetName string // Recover to named restore point
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TargetLSN string // Recover to Log Sequence Number
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TargetImmediate bool // Recover as soon as consistent state is reached
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TargetInclusive bool // Include target transaction
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RecoveryEndAction string // "pause", "promote", "shutdown"
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}
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// NewPITRManager creates a new PITR manager
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func NewPITRManager(cfg *config.Config, log logger.Logger) *PITRManager {
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return &PITRManager{
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cfg: cfg,
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log: log,
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}
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}
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// EnablePITR configures PostgreSQL for PITR by modifying postgresql.conf
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func (pm *PITRManager) EnablePITR(ctx context.Context, archiveDir string) error {
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pm.log.Info("Enabling PITR (Point-in-Time Recovery)", "archive_dir", archiveDir)
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// Ensure archive directory exists
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if err := os.MkdirAll(archiveDir, 0700); err != nil {
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return fmt.Errorf("failed to create WAL archive directory: %w", err)
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}
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// Find postgresql.conf location
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confPath, err := pm.findPostgreSQLConf(ctx)
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if err != nil {
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return fmt.Errorf("failed to locate postgresql.conf: %w", err)
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}
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pm.log.Info("Found PostgreSQL configuration", "path", confPath)
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// Backup original configuration
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backupPath := confPath + ".backup." + time.Now().Format("20060102_150405")
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if err := pm.backupFile(confPath, backupPath); err != nil {
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return fmt.Errorf("failed to backup postgresql.conf: %w", err)
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}
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pm.log.Info("Created configuration backup", "backup", backupPath)
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// Get absolute path to dbbackup binary
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dbbackupPath, err := os.Executable()
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if err != nil {
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return fmt.Errorf("failed to get dbbackup executable path: %w", err)
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}
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// Build archive command that calls dbbackup
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archiveCommand := fmt.Sprintf("%s wal archive %%p %%f --archive-dir %s", dbbackupPath, archiveDir)
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// Settings to enable PITR
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settings := map[string]string{
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"wal_level": "replica", // Required for PITR
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"archive_mode": "on",
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"archive_command": archiveCommand,
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"max_wal_senders": "3",
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"wal_keep_size": "1GB", // Keep at least 1GB of WAL
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}
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// Update postgresql.conf
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if err := pm.updatePostgreSQLConf(confPath, settings); err != nil {
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return fmt.Errorf("failed to update postgresql.conf: %w", err)
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}
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pm.log.Info("✅ PITR configuration updated successfully")
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pm.log.Warn("⚠️ PostgreSQL restart required for changes to take effect")
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pm.log.Info("To restart PostgreSQL:")
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pm.log.Info(" sudo systemctl restart postgresql")
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pm.log.Info(" OR: sudo pg_ctlcluster <version> <cluster> restart")
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return nil
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}
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// DisablePITR disables PITR by setting archive_mode = off
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func (pm *PITRManager) DisablePITR(ctx context.Context) error {
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pm.log.Info("Disabling PITR")
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confPath, err := pm.findPostgreSQLConf(ctx)
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if err != nil {
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return fmt.Errorf("failed to locate postgresql.conf: %w", err)
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}
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// Backup configuration
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backupPath := confPath + ".backup." + time.Now().Format("20060102_150405")
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if err := pm.backupFile(confPath, backupPath); err != nil {
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return fmt.Errorf("failed to backup postgresql.conf: %w", err)
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}
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settings := map[string]string{
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"archive_mode": "off",
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"archive_command": "", // Clear command
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}
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if err := pm.updatePostgreSQLConf(confPath, settings); err != nil {
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return fmt.Errorf("failed to update postgresql.conf: %w", err)
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}
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pm.log.Info("✅ PITR disabled successfully")
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pm.log.Warn("⚠️ PostgreSQL restart required")
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return nil
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}
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// GetCurrentPITRConfig reads current PITR settings from PostgreSQL
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func (pm *PITRManager) GetCurrentPITRConfig(ctx context.Context) (*PITRConfig, error) {
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confPath, err := pm.findPostgreSQLConf(ctx)
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if err != nil {
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return nil, err
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}
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file, err := os.Open(confPath)
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if err != nil {
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return nil, fmt.Errorf("failed to open postgresql.conf: %w", err)
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}
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defer file.Close()
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config := &PITRConfig{}
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scanner := bufio.NewScanner(file)
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for scanner.Scan() {
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line := strings.TrimSpace(scanner.Text())
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// Skip comments and empty lines
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if line == "" || strings.HasPrefix(line, "#") {
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continue
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}
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// Parse key = value
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parts := strings.SplitN(line, "=", 2)
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if len(parts) != 2 {
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continue
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}
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key := strings.TrimSpace(parts[0])
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value := strings.Trim(strings.TrimSpace(parts[1]), "'\"")
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switch key {
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case "wal_level":
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config.WALLevel = value
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case "archive_mode":
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config.ArchiveMode = value
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config.Enabled = (value == "on" || value == "always")
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case "archive_command":
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config.ArchiveCommand = value
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case "max_wal_senders":
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fmt.Sscanf(value, "%d", &config.MaxWALSenders)
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case "wal_keep_size":
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config.WALKeepSize = value
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case "restore_command":
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config.RestoreCommand = value
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}
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}
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if err := scanner.Err(); err != nil {
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return nil, fmt.Errorf("error reading postgresql.conf: %w", err)
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}
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return config, nil
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}
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// CreateRecoveryConf creates recovery configuration for PITR restore
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// PostgreSQL 12+: Creates recovery.signal and modifies postgresql.conf
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// PostgreSQL <12: Creates recovery.conf
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func (pm *PITRManager) CreateRecoveryConf(ctx context.Context, dataDir string, target RecoveryTarget, walArchiveDir string) error {
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pm.log.Info("Creating recovery configuration", "data_dir", dataDir)
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// Detect PostgreSQL version to determine recovery file format
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version, err := pm.getPostgreSQLVersion(ctx)
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if err != nil {
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pm.log.Warn("Could not detect PostgreSQL version, assuming >= 12", "error", err)
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version = 12 // Default to newer format
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}
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if version >= 12 {
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return pm.createRecoverySignal(ctx, dataDir, target, walArchiveDir)
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} else {
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return pm.createLegacyRecoveryConf(dataDir, target, walArchiveDir)
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}
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}
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// createRecoverySignal creates recovery.signal for PostgreSQL 12+
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func (pm *PITRManager) createRecoverySignal(ctx context.Context, dataDir string, target RecoveryTarget, walArchiveDir string) error {
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// Create recovery.signal file (empty file that triggers recovery mode)
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signalPath := filepath.Join(dataDir, "recovery.signal")
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if err := os.WriteFile(signalPath, []byte{}, 0600); err != nil {
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return fmt.Errorf("failed to create recovery.signal: %w", err)
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}
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pm.log.Info("Created recovery.signal", "path", signalPath)
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// Recovery settings go in postgresql.auto.conf (PostgreSQL 12+)
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autoConfPath := filepath.Join(dataDir, "postgresql.auto.conf")
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// Build recovery settings
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var settings []string
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settings = append(settings, fmt.Sprintf("restore_command = 'cp %s/%%f %%p'", walArchiveDir))
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if target.TargetTime != nil {
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settings = append(settings, fmt.Sprintf("recovery_target_time = '%s'", target.TargetTime.Format("2006-01-02 15:04:05")))
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} else if target.TargetXID != "" {
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settings = append(settings, fmt.Sprintf("recovery_target_xid = '%s'", target.TargetXID))
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} else if target.TargetName != "" {
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settings = append(settings, fmt.Sprintf("recovery_target_name = '%s'", target.TargetName))
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} else if target.TargetLSN != "" {
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settings = append(settings, fmt.Sprintf("recovery_target_lsn = '%s'", target.TargetLSN))
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} else if target.TargetImmediate {
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settings = append(settings, "recovery_target = 'immediate'")
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}
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if target.RecoveryEndAction != "" {
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settings = append(settings, fmt.Sprintf("recovery_target_action = '%s'", target.RecoveryEndAction))
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}
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// Append to postgresql.auto.conf
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f, err := os.OpenFile(autoConfPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
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if err != nil {
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return fmt.Errorf("failed to open postgresql.auto.conf: %w", err)
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}
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defer f.Close()
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if _, err := f.WriteString("\n# PITR Recovery Configuration (added by dbbackup)\n"); err != nil {
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return err
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}
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for _, setting := range settings {
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if _, err := f.WriteString(setting + "\n"); err != nil {
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return err
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}
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}
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pm.log.Info("Recovery configuration added to postgresql.auto.conf", "path", autoConfPath)
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return nil
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}
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// createLegacyRecoveryConf creates recovery.conf for PostgreSQL < 12
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func (pm *PITRManager) createLegacyRecoveryConf(dataDir string, target RecoveryTarget, walArchiveDir string) error {
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recoveryConfPath := filepath.Join(dataDir, "recovery.conf")
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var content strings.Builder
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content.WriteString("# Recovery Configuration (created by dbbackup)\n")
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content.WriteString(fmt.Sprintf("restore_command = 'cp %s/%%f %%p'\n", walArchiveDir))
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if target.TargetTime != nil {
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content.WriteString(fmt.Sprintf("recovery_target_time = '%s'\n", target.TargetTime.Format("2006-01-02 15:04:05")))
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}
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// Add other target types...
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if err := os.WriteFile(recoveryConfPath, []byte(content.String()), 0600); err != nil {
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return fmt.Errorf("failed to create recovery.conf: %w", err)
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}
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pm.log.Info("Created recovery.conf", "path", recoveryConfPath)
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return nil
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}
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// Helper functions
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func (pm *PITRManager) findPostgreSQLConf(ctx context.Context) (string, error) {
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// Try common locations
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commonPaths := []string{
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"/var/lib/postgresql/data/postgresql.conf",
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"/etc/postgresql/*/main/postgresql.conf",
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"/usr/local/pgsql/data/postgresql.conf",
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}
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for _, pattern := range commonPaths {
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matches, _ := filepath.Glob(pattern)
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for _, path := range matches {
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if _, err := os.Stat(path); err == nil {
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return path, nil
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}
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}
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}
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// Try to get from PostgreSQL directly
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cmd := exec.CommandContext(ctx, "psql", "-U", pm.cfg.User, "-t", "-c", "SHOW config_file")
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output, err := cmd.Output()
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if err == nil {
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path := strings.TrimSpace(string(output))
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if _, err := os.Stat(path); err == nil {
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return path, nil
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}
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}
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return "", fmt.Errorf("could not locate postgresql.conf. Please specify --pg-conf-path")
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}
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func (pm *PITRManager) backupFile(src, dst string) error {
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input, err := os.ReadFile(src)
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if err != nil {
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return err
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}
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return os.WriteFile(dst, input, 0644)
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}
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func (pm *PITRManager) updatePostgreSQLConf(confPath string, settings map[string]string) error {
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file, err := os.Open(confPath)
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if err != nil {
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return err
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}
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defer file.Close()
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var lines []string
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existingKeys := make(map[string]bool)
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scanner := bufio.NewScanner(file)
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// Read existing configuration and track which keys are already present
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for scanner.Scan() {
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line := scanner.Text()
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lines = append(lines, line)
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// Check if this line sets one of our keys
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for key := range settings {
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if matched, _ := regexp.MatchString(fmt.Sprintf(`^\s*%s\s*=`, key), line); matched {
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existingKeys[key] = true
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}
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}
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}
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if err := scanner.Err(); err != nil {
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return err
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}
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// Append missing settings
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for key, value := range settings {
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if !existingKeys[key] {
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if value == "" {
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lines = append(lines, fmt.Sprintf("# %s = '' # Disabled by dbbackup", key))
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} else {
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lines = append(lines, fmt.Sprintf("%s = '%s' # Added by dbbackup", key, value))
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}
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}
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}
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// Write updated configuration
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output := strings.Join(lines, "\n") + "\n"
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return os.WriteFile(confPath, []byte(output), 0644)
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}
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func (pm *PITRManager) getPostgreSQLVersion(ctx context.Context) (int, error) {
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cmd := exec.CommandContext(ctx, "psql", "-U", pm.cfg.User, "-t", "-c", "SHOW server_version")
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output, err := cmd.Output()
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if err != nil {
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return 0, err
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}
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versionStr := strings.TrimSpace(string(output))
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var major int
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fmt.Sscanf(versionStr, "%d", &major)
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return major, nil
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}
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Block a user