mod_reqin_log/scripts/socket_consumer.py

#!/usr/bin/env python3
"""
socket_consumer.py - Unix socket consumer for mod_reqin_log

This script creates a Unix domain socket server that receives JSON log lines
from the mod_reqin_log Apache module. It is primarily used for testing and
development purposes.

Usage:
    python3 socket_consumer.py [socket_path]

Example:
    python3 socket_consumer.py /var/run/mod_reqin_log.sock
"""

import socket
import os
import sys
import json
import signal
import argparse
from datetime import datetime

# Default socket path
# Use /var/run for production (more secure than /tmp)
DEFAULT_SOCKET_PATH = os.environ.get("MOD_REQIN_LOG_SOCKET", "/var/run/mod_reqin_log.sock")

# Global flag for graceful shutdown
shutdown_requested = False


def signal_handler(signum, frame):
    """Handle shutdown signals gracefully."""
    global shutdown_requested
    shutdown_requested = True
    print("\nShutdown requested, finishing current operations...")


def parse_args():
    """Parse command line arguments."""
    parser = argparse.ArgumentParser(
        description="Unix socket consumer for mod_reqin_log"
    )
    parser.add_argument(
        "socket_path",
        nargs="?",
        default=DEFAULT_SOCKET_PATH,
        help=f"Path to Unix socket (default: {DEFAULT_SOCKET_PATH})"
    )
    parser.add_argument(
        "-q", "--quiet",
        action="store_true",
        help="Suppress log output"
    )
    parser.add_argument(
        "-o", "--output",
        type=str,
        help="Write logs to file instead of stdout"
    )
    parser.add_argument(
        "--validate-json",
        action="store_true",
        help="Validate JSON and pretty-print"
    )
    return parser.parse_args()


def create_socket(socket_path):
    """Create and bind Unix domain socket."""
    # Remove existing socket file
    if os.path.exists(socket_path):
        os.remove(socket_path)
    
    # Create socket
    server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server.bind(socket_path)
    server.listen(5)
    
    # Set permissions (owner and group only, not world-writable)
    # Apache user must be in the socket's group to connect
    os.chmod(socket_path, 0o660)
    
    return server


def process_log_line(line, validate_json=False, output_file=None):
    """Process a single log line."""
    line = line.strip()
    if not line:
        return
    
    if validate_json:
        try:
            log_entry = json.loads(line)
            line = json.dumps(log_entry, indent=2)
        except json.JSONDecodeError as e:
            line = f"[INVALID JSON] {line}\nError: {e}"
    
    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    output = f"[{timestamp}] {line}"
    
    if output_file:
        output_file.write(output + "\n")
        output_file.flush()
    else:
        print(output)


def handle_client(conn, validate_json=False, output_file=None):
    """Handle a client connection."""
    data = b""
    try:
        while not shutdown_requested:
            chunk = conn.recv(4096)
            if not chunk:
                break
            
            data += chunk
            
            # Process complete lines
            while b"\n" in data:
                newline_pos = data.index(b"\n")
                line = data[:newline_pos].decode("utf-8", errors="replace")
                data = data[newline_pos + 1:]
                process_log_line(line, validate_json, output_file)
    except Exception as e:
        print(f"Error handling client: {e}", file=sys.stderr)
    finally:
        # Process any remaining data
        if data:
            line = data.decode("utf-8", errors="replace")
            process_log_line(line, validate_json, output_file)
        conn.close()


def main():
    """Main entry point."""
    args = parse_args()
    
    # Setup signal handlers
    signal.signal(signal.SIGINT, signal_handler)
    signal.signal(signal.SIGTERM, signal_handler)
    
    output_file = None
    if args.output:
        output_file = open(args.output, "a")
    
    try:
        # Create socket
        server = create_socket(args.socket_path)
        print(f"Listening on {args.socket_path}", file=sys.stderr)
        if not args.quiet:
            print(f"Waiting for connections... (Ctrl+C to stop)", file=sys.stderr)
        
        # Accept connections
        while not shutdown_requested:
            try:
                server.settimeout(1.0)
                try:
                    conn, addr = server.accept()
                except socket.timeout:
                    continue
                
                # Handle client in same thread for simplicity
                handle_client(conn, args.validate_json, output_file)
            except Exception as e:
                if not shutdown_requested:
                    print(f"Accept error: {e}", file=sys.stderr)
    
    except Exception as e:
        print(f"Fatal error: {e}", file=sys.stderr)
        return 1
    
    finally:
        # Cleanup
        if os.path.exists(args.socket_path):
            os.remove(args.socket_path)
        if output_file:
            output_file.close()
        print("Socket consumer stopped.", file=sys.stderr)
    
    return 0


if __name__ == "__main__":
    sys.exit(main())