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Application Logs

Most application logs are piped to either stdout or stderr, which automatically get streamed to your app's unified log stream. In some cases, your app may log to a file or files. Rather than having to remotely connect to your app to view these logs, Nanobox lets you pipe them into your unified log stream through the use of the log_watch boxfile config.

log_watch

A log_watch conists of the following:

  • Key - This is prepended to log entries originating from the log_watch'd file. Keys must be unique.
  • Filepath - The absolute path to the log file. Your app lives in /app.

log_watch

# Pattern
web.site:
  log_watch:
    key: /app/path/to/log.file

# Example
web.site:
  log_watch:
    admin[error]: /app/logs/admin_error.log
    api[auth]: /app/logs/api_auth.log

You Can Only log_watch Individual Files

Log watches only work on individual files. You cannot log_watch a directory.

Log Filepaths Must Be Absolute

When specifying the path to your log file, the filepath should be absolute. Your app lives in the /app directory, so be sure that's at the beginning of the filepath.

Key Naming Restrictions

Log_watch "keys" cannot contain special characters other than brackets []. For logs captured by Nanobox, we use the following pattern: abc124[abc123], but you're not bound to this.

Keys Must Be Unique

Log_watch keys must be unique. If you have identical keys, only one will be watched and there's no guarantee which one it will be.

Log_watch'd Files Are Writable

Any files specified as a log_watch will be given writable permissions. These files do not need to be stored in a network directory.

Logs Aren't Actually Written to log_watch'd Files

While logwatch'd files have writable permissions, the files themselves don't actually get updated. Logwatch'd files are symlinked to a centralized file that is piped into the unified log stream. If you remotely connect to your component and inspect log_watch'd files, you'll see the contents of the centralized log file.

Reach out to help@nanobox.io and we'll try to help.