Syslog Integration

LightNVR supports logging to syslog for easier system integration and centralized log management.

Overview

When syslog is enabled, LightNVR will send log messages to the system's syslog daemon in addition to the regular log file and console output. This provides several benefits:

• Centralized Logging: Integrate with system-wide log management tools
• Remote Logging: Forward logs to remote syslog servers for centralized monitoring
• Log Rotation: Leverage system log rotation policies
• Integration with Monitoring Tools: Use tools like journalctl, rsyslog, or syslog-ng
• Standardized Format: Follow standard syslog conventions for log levels and formatting

Configuration

Syslog can be enabled and configured in the lightnvr.ini configuration file under the [general] section:

[general]
pid_file = /var/run/lightnvr.pid
log_file = /var/log/lightnvr.log
log_level = 2  ; 0=ERROR, 1=WARN, 2=INFO, 3=DEBUG
syslog_enabled = true  ; Enable logging to syslog
syslog_ident = lightnvr  ; Syslog identifier (application name)
syslog_facility = LOG_USER  ; Syslog facility

Configuration Options

• syslog_enabled (boolean): Enable or disable syslog logging

  • Default: false
  • Set to true to enable syslog integration

• syslog_ident (string): Syslog identifier/application name

  • Default: "lightnvr"
  • This identifier appears in syslog messages and can be used for filtering
  • Maximum length: 63 characters

• syslog_facility (string or integer): Syslog facility for categorizing messages

  • Default: LOG_USER
  • Valid values:
    • LOG_USER (8): User-level messages (default)
    • LOG_DAEMON (24): System daemon messages
    • LOG_LOCAL0 (128) through LOG_LOCAL7 (184): Local use facilities for custom applications
  • Can be specified as either the name (e.g., LOG_USER) or numeric value (e.g., 8)

Log Level Mapping

LightNVR log levels are mapped to syslog priorities as follows:

LightNVR Level	Syslog Priority	Description
ERROR (0)	LOG_ERR (3)	Error conditions
WARN (1)	LOG_WARNING (4)	Warning conditions
INFO (2)	LOG_INFO (6)	Informational messages
DEBUG (3)	LOG_DEBUG (7)	Debug-level messages

Viewing Syslog Messages

Using journalctl (systemd-based systems)

# View all LightNVR logs
journalctl -t lightnvr

# Follow logs in real-time
journalctl -t lightnvr -f

# View logs from the last hour
journalctl -t lightnvr --since "1 hour ago"

# View logs with specific priority
journalctl -t lightnvr -p err  # Only errors
journalctl -t lightnvr -p warning  # Warnings and above

# View logs for a specific time range
journalctl -t lightnvr --since "2024-01-01 00:00:00" --until "2024-01-01 23:59:59"

Using traditional syslog

On systems using traditional syslog (rsyslog, syslog-ng), logs will appear in:

• /var/log/syslog (Debian/Ubuntu)
• /var/log/messages (RHEL/CentOS)

# View LightNVR logs
tail -f /var/log/syslog | grep lightnvr

# Search for specific messages
grep lightnvr /var/log/syslog

Production Deployment

For production deployments, it's recommended to:

1. Enable syslog for centralized logging and monitoring
2. Use a dedicated facility (e.g., LOG_LOCAL0) to separate LightNVR logs from other applications
3. Configure log rotation through your syslog daemon
4. Set up remote logging if using centralized log management

Example Production Configuration

[general]
syslog_enabled = true
syslog_ident = lightnvr
syslog_facility = LOG_LOCAL0

Configuring rsyslog for Remote Logging

To forward LightNVR logs to a remote syslog server, add to /etc/rsyslog.d/lightnvr.conf:

# Forward LightNVR logs to remote server
local0.* @@remote-log-server:514

Then restart rsyslog:

sudo systemctl restart rsyslog

Behavior

• Dual Output: When syslog is enabled, messages are sent to BOTH syslog AND the regular log file/console
• No Performance Impact: Syslog writes are asynchronous and don't block the application
• Automatic PID: The process ID is automatically included in syslog messages
• Graceful Fallback: If syslog is unavailable, messages still go to the log file and console

Troubleshooting

Syslog messages not appearing

1. Check that syslog is enabled in the configuration:

   grep syslog_enabled /etc/lightnvr/lightnvr.ini
   

2. Verify the syslog daemon is running:

   sudo systemctl status rsyslog  # or syslog-ng
   

3. Check syslog configuration for filtering rules that might be blocking messages

4. Verify permissions - LightNVR needs to be able to write to /dev/log

Messages appearing with wrong facility

Check the syslog_facility setting in the configuration file and ensure it matches your syslog daemon's configuration.

API

The syslog functionality is exposed through the following C API functions:

// Enable syslog logging
int enable_syslog(const char *ident, int facility);

// Disable syslog logging
void disable_syslog(void);

// Check if syslog is enabled
int is_syslog_enabled(void);

These functions are automatically called during LightNVR initialization based on the configuration file settings.