fix: respect NODE_DB_PATH environment variable in Docker (fixes #40)

- Fixed docker-entrypoint.sh to use NODE_DB_PATH instead of hardcoded paths
- Added log_message() helper to prevent stdio mode output corruption
- Fixed directory creation race condition with proper ownership
- Added path validation to ensure NODE_DB_PATH ends with .db
- Updated rebuild.ts to respect NODE_DB_PATH environment variable
- Added comprehensive documentation for custom database paths
- Bumped version to 2.7.16

The bug was caused by hardcoded /app/data/nodes.db paths in the Docker
entrypoint script that ignored the NODE_DB_PATH environment variable.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

docker/docker-entrypoint.sh

@@ -1,39 +1,75 @@
 #!/bin/sh
 set -e
 
+# Helper function for safe logging (prevents stdio mode corruption)
+log_message() {
+    [ "$MCP_MODE" != "stdio" ] && echo "$@"
+}
+
 # Environment variable validation
 if [ "$MCP_MODE" = "http" ] && [ -z "$AUTH_TOKEN" ] && [ -z "$AUTH_TOKEN_FILE" ]; then
-    echo "ERROR: AUTH_TOKEN or AUTH_TOKEN_FILE is required for HTTP mode"
+    log_message "ERROR: AUTH_TOKEN or AUTH_TOKEN_FILE is required for HTTP mode" >&2
     exit 1
 fi
 
 # Validate AUTH_TOKEN_FILE if provided
 if [ -n "$AUTH_TOKEN_FILE" ] && [ ! -f "$AUTH_TOKEN_FILE" ]; then
-    echo "ERROR: AUTH_TOKEN_FILE specified but file not found: $AUTH_TOKEN_FILE"
+    log_message "ERROR: AUTH_TOKEN_FILE specified but file not found: $AUTH_TOKEN_FILE" >&2
     exit 1
 fi
 
+# Database path configuration - respect NODE_DB_PATH if set
+if [ -n "$NODE_DB_PATH" ]; then
+    # Basic validation - must end with .db
+    case "$NODE_DB_PATH" in
+        *.db) ;;
+        *) log_message "ERROR: NODE_DB_PATH must end with .db" >&2; exit 1 ;;
+    esac
+    
+    # Use the path as-is (Docker paths should be absolute anyway)
+    DB_PATH="$NODE_DB_PATH"
+else
+    DB_PATH="/app/data/nodes.db"
+fi
+
+DB_DIR=$(dirname "$DB_PATH")
+
+# Ensure database directory exists with correct ownership
+if [ ! -d "$DB_DIR" ]; then
+    log_message "Creating database directory: $DB_DIR"
+    if [ "$(id -u)" = "0" ]; then
+        # Create as root but immediately fix ownership
+        mkdir -p "$DB_DIR" && chown nodejs:nodejs "$DB_DIR"
+    else
+        mkdir -p "$DB_DIR"
+    fi
+fi
+
 # Database initialization with file locking to prevent race conditions
-if [ ! -f "/app/data/nodes.db" ]; then
-    echo "Database not found. Initializing..."
+if [ ! -f "$DB_PATH" ]; then
+    log_message "Database not found at $DB_PATH. Initializing..."
     # Use a lock file to prevent multiple containers from initializing simultaneously
     (
         flock -x 200
         # Double-check inside the lock
-        if [ ! -f "/app/data/nodes.db" ]; then
-            echo "Initializing database..."
-            cd /app && node dist/scripts/rebuild.js || {
-                echo "ERROR: Database initialization failed"
+        if [ ! -f "$DB_PATH" ]; then
+            log_message "Initializing database at $DB_PATH..."
+            cd /app && NODE_DB_PATH="$DB_PATH" node dist/scripts/rebuild.js || {
+                log_message "ERROR: Database initialization failed" >&2
                 exit 1
             }
         fi
-    ) 200>/app/data/.db.lock
+    ) 200>"$DB_DIR/.db.lock"
 fi
 
 # Fix permissions if running as root (for development)
 if [ "$(id -u)" = "0" ]; then
-    echo "Running as root, fixing permissions..."
-    chown -R nodejs:nodejs /app/data
+    log_message "Running as root, fixing permissions..."
+    chown -R nodejs:nodejs "$DB_DIR"
+    # Also ensure /app/data exists for backward compatibility
+    if [ -d "/app/data" ]; then
+        chown -R nodejs:nodejs /app/data
+    fi
     # Switch to nodejs user (using Alpine's native su)
     exec su nodejs -c "$*"
 fi