Log Watcher

The Log Watcher (aka File Watcher) allows the Notifiarr Client to monitor log files for lines matching regular expressions. This is similar to tail -f file | grep pattern - you get notifications when log files contain new lines matching your patterns.

Configuration

Add a new Log Watcher entry in the Notifiarr Client UI under Configuration > Log Watch.

Fields

Field	Required	Default	Description
Path	Yes	-	Full path to the log file to watch
Regex	Yes	-	Regular expression to match - matching lines trigger notifications
Skip	No	empty	Regular expression for lines to ignore (even if they match Regex)
Poll	No	`false`	Use polling instead of inotify (useful for network mounts)
Pipe	No	`false`	Treat path as a named pipe (FIFO) instead of a file
Must Exist	No	`false`	Fail if the file doesn't exist at startup
Log Match	No	`true`	Log matched lines to notifiarr debug log

Regex Tips

Use (?i) at the start for case-insensitive matching
Use | to match multiple patterns: error|warn|fatal
Escape special characters: \[, \., \|
If your skip expression contains ', replace it with .?

Community Patterns

*arr Applications

These patterns catch warnings, errors, and stack traces while filtering common noise.

Radarr

Path:

/var/log/radarr/radarr.debug.txt

Regex:

(?i)(\|warn\||\|error\||^\[v[0-9].+\]|database is locked)

Why this regex?

(?i) - Case-insensitive matching for all patterns
\|warn\| - Matches |Warn| log level delimiter in *arr logs
\|error\| - Matches |Error| log level delimiter
^\[v[0-9].+\] - Matches stack traces that start with any version header (v4, v5, v6, etc.)
database is locked - SQLite locking issues that indicate problems

Skip:

(?i)Download client failed to add torrent|Movie with IMDBId|It will not be added|Invalid date found|Validation failed|An unhandled exception has occurred while executing the request.|HttpClient error|TaskManager failed while processing|Task Error|Name does not resolve|429.TooManyRequests

Why skip these?

Download client failed to add torrent - Usually duplicate detection, not a real error
Movie with IMDBId / It will not be added - Informational about skipped movies
Invalid date found - Common indexer feed parsing noise
Validation failed - API validation errors (usually user input issues)
An unhandled exception... - Generic wrapper, the actual error is elsewhere
HttpClient error - Transient network issues that resolve themselves
TaskManager failed / Task Error - Background task noise
Name does not resolve - DNS failures that are usually transient
429.TooManyRequests - Rate limiting (expected behavior)

Sonarr

Path:

/var/log/sonarr/sonarr.debug.txt

Regex:

(?i)(\|warn\||\|error\||^\[v[0-9].+\]|database is locked)

Why this regex?

Same pattern as Radarr - matches warnings, errors, stack traces, and database locks

Skip:

(?i)Download client failed to add torrent|Invalid date found|Validation failed|An unhandled exception has occurred while executing the request.|Unable to find exact quality|HttpClient error|TaskManager failed while processing|Task Error|Name does not resolve|InvalidDateException|429.TooManyRequests

Why skip these?

Same reasons as Radarr, plus:
Unable to find exact quality - Quality parsing noise from release names
InvalidDateException - Date parsing errors from indexers

Prowlarr

Path:

/var/log/prowlarr/prowlarr.debug.txt

Regex:

(?i)(\|warn\||\|error\||^\[v[0-9].+\])

Skip:

(?i)Validation failed|An unhandled exception has occurred while executing the request|(?:CinemaZ|PrivateHD)[.a-z0-9/=&?: ]+404\.NotFound|HttpClient error|System.Net.CookieException|TaskManager failed while processing|Task Error|Name does not resolve|NzbDrone.Common.Http.HttpException: HTTP request failed|Retrying in

Why skip these?

(?:CinemaZ|PrivateHD)...404 - Known indexers that return 404 for certain searches
System.Net.CookieException - Cookie handling issues that don't affect functionality
HTTP request failed / Retrying in - Transient errors with automatic retry

Readarr

Path:

/var/log/readarr/readarr.debug.txt

Regex:

(?i)(\|warn\||\|error\||^\[v[0-9].+\])

Skip:

(?i)Validation failed|An unhandled exception has occurred while executing the request.|HttpClient error

Lidarr

Path:

/var/log/lidarr/lidarr.debug.txt

Regex:

(?i)(\|warn\||\|error\||^\[v[0-9].+\])

Skip:

(?i)Validation failed|An unhandled exception has occurred while executing the request.|HttpClient error

Other Applications

Kometa (formerly Plex Meta Manager)

Path:

/var/log/kometa/meta.log

Regex:

(?i)(\[ERROR\]|\[CRITICAL\])

Why this regex?

Kometa uses [ERROR] and [CRITICAL] log level markers
Only matches actual errors, not warnings (which are often informational)

Skip:

(?i)Convert Error:|ID not found|TVDb Error: Name not found|Plex Error: No Items found in Plex|Trakt Error: No TVDb ID found for|TMDb Error: No Movie found for TMDb ID

Why skip these?

Convert Error - Image conversion issues that don't affect functionality
ID not found / Name not found - Missing metadata that can't be fixed
No Items found in Plex - Empty collections (expected for new libraries)
No TVDb ID found / No Movie found - External service lookup failures

Nginx Error Log

Path:

/var/log/nginx/error.log

Regex:

(?i)(emerg|alert|crit|\[error\].*upstream.*failed|502|503|504|connect\(\) failed|no live upstreams)

Why this regex?

emerg|alert|crit - Nginx severity levels for serious issues
\[error\].*upstream.*failed - Backend connection failures
502|503|504 - Gateway errors indicating backend problems
connect\(\) failed - Can't reach upstream servers
no live upstreams - All backends are down

Skip:

(?i)(client closed connection|upstream timed out.*reading response header|recv\(\) failed|connection reset by peer|SSL_do_handshake)

Why skip these?

client closed connection - User navigated away or closed browser
upstream timed out - Often caused by slow backends, not errors
recv\(\) failed / connection reset - Network glitches
SSL_do_handshake - SSL negotiation failures from bots/scanners

Rustic Backup

Path:

/var/log/rustic/rustic.log

Regex:

(\[ERROR\]|\[WARN\]|starting to backup|successfully saved|backup of.*done)

Why this regex?

\[ERROR\]|\[WARN\] - Actual problems with backups
starting to backup - Notification that backup started
successfully saved|backup of.*done - Confirmation backup completed

Skip:

(?i)(flush_task.*graceful shutdown|Requesting graceful shutdown|read_end_buffer_size|write_end_buffer_size|repository opendal.*password is correct)

Why skip these?

graceful shutdown - Normal shutdown messages
buffer_size - Configuration warnings that don't affect functionality
password is correct - Informational message, not an error

Pattern Reference

Common *arr Log Patterns

Pattern	Matches
`\\|warn\\|`	Warning log level in *arr format: `2024-01-30 12:00:00.000\\|Warn\\|...`
`\\|error\\|`	Error log level in *arr format
`^\[v[0-9].+\]`	Stack traces that start with any version header (e.g., `[v5.0.0.1234]`)
`database is locked`	SQLite concurrency issues

Common Skip Patterns

Pattern	Reason to Skip
`Invalid date found`	Indexer feed parsing - benign noise
`Validation failed`	User input issues, not system errors
`HttpClient error`	Transient network issues that auto-resolve
`429.TooManyRequests`	Rate limiting - expected behavior
`Name does not resolve`	DNS failures - usually transient
`Download client failed to add torrent`	Usually duplicate detection

Troubleshooting

File Not Being Watched

Verify the path exists: ls -la /path/to/log
Check file permissions - notifiarr user must have read access
Try enabling Poll for network-mounted files
Check notifiarr logs: journalctl -u notifiarr | grep -i watch

Too Many Notifications

Add patterns to Skip for false positives
Use more specific Regex patterns
Consider watching .debug.txt instead of .txt for less verbose logs

No Notifications

Test your regex at regex101.com with Go flavor
Verify the watcher is not disabled
Check that lines actually match with: tail -f /path/to/log | grep -E 'your-regex'
Review notifiarr debug log for "watch" entries