feat: enhance Raft log index retrieval and data directory management

- Improved the `getRaftLogIndex` method to accurately report the Raft log index by incorporating fallback logic to read persisted snapshot metadata when the RQLite status is unavailable or returns zero.
- Added a new method `getPersistedRaftLogIndex` to read the highest Raft log index from snapshot metadata files, ensuring accurate reporting even before RQLite starts.
- Centralized the data directory path resolution logic in `rqliteDataDirPath`, simplifying the codebase and enhancing maintainability.

CHANGELOG.md

@@ -13,6 +13,19 @@ The format is based on [Keep a Changelog][keepachangelog] and adheres to [Semant
 ### Deprecated
 
 ### Fixed
+## [0.64.1] - 2025-11-10
+
+### Added
+\n
+### Changed
+- Improved the accuracy of the Raft log index reporting by falling back to reading persisted snapshot metadata from disk if the running RQLite instance is not yet reachable or reports a zero index.
+
+### Deprecated
+
+### Removed
+
+### Fixed
+\n
 ## [0.64.0] - 2025-11-10
 
 ### Added

Makefile

@@ -19,7 +19,7 @@ test-e2e:
 
 .PHONY: build clean test run-node run-node2 run-node3 run-example deps tidy fmt vet lint clear-ports install-hooks kill
 
-VERSION := 0.64.0
+VERSION := 0.64.1
 COMMIT  ?= $(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)
 DATE    ?= $(shell date -u +%Y-%m-%dT%H:%M:%SZ)
 LDFLAGS := -X 'main.version=$(VERSION)' -X 'main.commit=$(COMMIT)' -X 'main.date=$(DATE)'

pkg/rqlite/data_safety.go

@@ -5,26 +5,98 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"os"
+	"path/filepath"
 	"time"
 
 	"go.uber.org/zap"
 )
 
 // getRaftLogIndex returns the current Raft log index for this node
+// It first tries to get the index from the running RQLite instance via /status endpoint.
+// If that fails or returns 0, it falls back to reading persisted snapshot metadata from disk.
+// This ensures accurate log index reporting even before RQLite is fully started.
 func (r *RQLiteManager) getRaftLogIndex() uint64 {
 	status, err := r.getRQLiteStatus()
-	if err != nil {
-		r.logger.Debug("Failed to get Raft log index", zap.Error(err))
+	if err == nil {
+		// Return the highest index we have from runtime status
+		maxIndex := status.Store.Raft.LastLogIndex
+		if status.Store.Raft.AppliedIndex > maxIndex {
+			maxIndex = status.Store.Raft.AppliedIndex
+		}
+		if status.Store.Raft.CommitIndex > maxIndex {
+			maxIndex = status.Store.Raft.CommitIndex
+		}
+
+		// If runtime status reports a valid index, use it
+		if maxIndex > 0 {
+			return maxIndex
+		}
+
+		// Runtime status returned 0, fall back to persisted snapshot metadata
+		// This handles the case where RQLite is running but hasn't applied any logs yet
+		if persisted := r.getPersistedRaftLogIndex(); persisted > 0 {
+			r.logger.Debug("Using persisted Raft log index because runtime status reported zero",
+				zap.Uint64("persisted_index", persisted))
+			return persisted
+		}
 		return 0
 	}
 
-	// Return the highest index we have
-	maxIndex := status.Store.Raft.LastLogIndex
-	if status.Store.Raft.AppliedIndex > maxIndex {
-		maxIndex = status.Store.Raft.AppliedIndex
+	// RQLite status endpoint is not available (not started yet or unreachable)
+	// Fall back to reading persisted snapshot metadata from disk
+	persisted := r.getPersistedRaftLogIndex()
+	if persisted > 0 {
+		r.logger.Debug("Using persisted Raft log index before RQLite is reachable",
+			zap.Uint64("persisted_index", persisted),
+			zap.Error(err))
+		return persisted
 	}
-	if status.Store.Raft.CommitIndex > maxIndex {
-		maxIndex = status.Store.Raft.CommitIndex
+
+	r.logger.Debug("Failed to get Raft log index", zap.Error(err))
+	return 0
+}
+
+// getPersistedRaftLogIndex reads the highest Raft log index from snapshot metadata files
+// This allows us to report accurate log indexes even before RQLite is started
+func (r *RQLiteManager) getPersistedRaftLogIndex() uint64 {
+	rqliteDataDir, err := r.rqliteDataDirPath()
+	if err != nil {
+		return 0
+	}
+
+	snapshotsDir := filepath.Join(rqliteDataDir, "rsnapshots")
+	entries, err := os.ReadDir(snapshotsDir)
+	if err != nil {
+		return 0
+	}
+
+	var maxIndex uint64
+	for _, entry := range entries {
+		// Only process directories (snapshot directories)
+		if !entry.IsDir() {
+			continue
+		}
+
+		// Read meta.json from the snapshot directory
+		metaPath := filepath.Join(snapshotsDir, entry.Name(), "meta.json")
+		raw, err := os.ReadFile(metaPath)
+		if err != nil {
+			continue
+		}
+
+		// Parse the metadata JSON to extract the Index field
+		var meta struct {
+			Index uint64 `json:"Index"`
+		}
+		if err := json.Unmarshal(raw, &meta); err != nil {
+			continue
+		}
+
+		// Track the highest index found
+		if meta.Index > maxIndex {
+			maxIndex = meta.Index
+		}
 	}
 
 	return maxIndex

pkg/rqlite/rqlite.go

@@ -123,8 +123,9 @@ func (r *RQLiteManager) Start(ctx context.Context) error {
 	return nil
 }
 
-// prepareDataDir expands and creates the RQLite data directory
-func (r *RQLiteManager) prepareDataDir() (string, error) {
+// rqliteDataDirPath returns the resolved path to the RQLite data directory
+// This centralizes the path resolution logic used throughout the codebase
+func (r *RQLiteManager) rqliteDataDirPath() (string, error) {
 	// Expand ~ in data directory path
 	dataDir := os.ExpandEnv(r.dataDir)
 	if strings.HasPrefix(dataDir, "~") {
@@ -135,8 +136,17 @@ func (r *RQLiteManager) prepareDataDir() (string, error) {
 		dataDir = filepath.Join(home, dataDir[1:])
 	}
 
+	return filepath.Join(dataDir, "rqlite"), nil
+}
+
+// prepareDataDir expands and creates the RQLite data directory
+func (r *RQLiteManager) prepareDataDir() (string, error) {
+	rqliteDataDir, err := r.rqliteDataDirPath()
+	if err != nil {
+		return "", err
+	}
+
 	// Create data directory
-	rqliteDataDir := filepath.Join(dataDir, "rqlite")
 	if err := os.MkdirAll(rqliteDataDir, 0755); err != nil {
 		return "", fmt.Errorf("failed to create RQLite data directory: %w", err)
 	}
@@ -689,16 +699,11 @@ func (r *RQLiteManager) recoverCluster(peersJSONPath string) error {
 	// Restart RQLite - it will automatically detect peers.json and perform recovery
 	r.logger.Info("Restarting RQLite (will auto-recover using peers.json)")
 
-	// Build the same args as original Start() - expand ~ in data directory
-	dataDir := os.ExpandEnv(r.dataDir)
-	if strings.HasPrefix(dataDir, "~") {
-		home, err := os.UserHomeDir()
-		if err != nil {
-			return fmt.Errorf("failed to determine home directory: %w", err)
-		}
-		dataDir = filepath.Join(home, dataDir[1:])
+	// Rebuild the launch arguments using the centralized path helper
+	rqliteDataDir, err := r.rqliteDataDirPath()
+	if err != nil {
+		return fmt.Errorf("failed to resolve RQLite data directory: %w", err)
 	}
-	rqliteDataDir := filepath.Join(dataDir, "rqlite")
 	args := []string{
 		"-http-addr", fmt.Sprintf("0.0.0.0:%d", r.config.RQLitePort),
 		"-http-adv-addr", r.discoverConfig.HttpAdvAddress,