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Logger persistence

Log entries received from PLC are stored to local filesystem by default:

  • log/data-logger-storage

Clean storage

To clean old log entries, delete data-logger-storage folder.

Storage size

By default 200'000 entries stored at persistence storage. Configuration at data/config.json:

logger.cacheSize: 200000

Filesystem storage

Since writing to filesystem is not that fast, it is not executed after each log message received.

Cyclic store

If cyclicStore at config.json is activated (by default true). Log messages stored to filesystem after no messages received for 5 seconds.

Shutdown hook store

Messages are stored to filesystem if application closed by shutdown hook.

For Windows user: consider that shutdown hook not called if console is closed with (X). But it is called if backend stopped with CTRL-C command.

For Linux/macOS users: shutdown hook works like expected.

Use offline Logger component

Use Logger and State Animation view with offline storage data:

  • Copy data-logger-storage folder, to analyze entries from another Service Ui instance.
  • For successful offline log view, valid plc-definition meta information must located at Service ui backend folder (generated by UP).
  • Use PLC target type "Simulation" at Configuration page for offline logger view.