2024.12.5
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System Log

The system_log integration stores information about all logged errors and warnings in Home Assistant. To view your logs, navigate to Settings -> System -> Logs. In order to not overload Home Assistant with log data, only the 50 last errors and warnings will be stored. Older entries are automatically discarded from the log. It is possible to change the number of stored log entries using the parameter max_entries.

Configuration

This integration is automatically loaded by the frontend (so no need to do anything if you are using the frontend). If you are not doing so, or if you wish to change a parameter, add the following section to your configuration.yamlThe configuration.yaml file is the main configuration file for Home Assistant. It lists the integrations to be loaded and their specific configurations. In some cases, the configuration needs to be edited manually directly in the configuration.yaml file. Most integrations can be configured in the UI. [Learn more] file:

system_log:
  max_entries: MAX_ENTRIES

Configuration Variables

Looking for your configuration file?
max_entries integer (Optional, default: 50)

Number of entries to store (older entries are discarded).

fire_event string (Optional, default: false)

Whether events are fired (required when used for triggers).

Actions

Action clear

To manually clear the system log, use this action.

Action write

Write a log entry

Data attribute Optional Description
message no Message to log
level yes Log level: debug, info, warning, error, critical. Defaults to ‘error’.
logger yes Logger name under which to log the message. Defaults to ‘system_log.external’.

Events

Errors and warnings are posted as the event system_log_event, so it is possible to write automations that trigger whenever a warning or error occurs. The following information is included in each event:

Field Description
level Either WARNING or ERROR depending on severity.
source File that triggered the error, e.g., core.py or media_player/yamaha.py.
exception Full stack trace if available, an empty string otherwise.
message Descriptive message of the error, e.g., “Error handling request”.
name Name of the integration, e.g., homeassistant.components.device_tracker
timestamp Unix timestamp with as a double, e.g., 1517241010.237416.

Live examples of these events can be found in the Home Assistant log file (home-assistant.log) or by just looking in the system log. An example could, for instance, look like this:

2019-02-14 16:20:35 ERROR (MainThread) [homeassistant.loader] Unable to find integration system_healt
2019-02-14 16:20:36 ERROR (MainThread) [homeassistant.components.device_tracker] Error setting up platform google_maps
Traceback (most recent call last):
  File "/home/fab/Documents/repos/ha/home-assistant/homeassistant/integrations/device_tracker/__init__.py", line 184, in
[...]

The message (“Unable to find integration system_healt”), name (homeassistant.loader) and level (ERROR) can easily be extracted from the log. The exact timestamp and if there is a stack trace that’s shown as well.

Examples

Here are some examples using the events posted by system_log. fire_event must be set to true for these to work.

Counting Number of Warnings

This will create a counter that increases every time a warning is logged:

counter:
  warning_counter:
    name: Warnings
    icon: mdi:alert

automation:
  - alias: "Count warnings"
    triggers:
      - trigger: event
        event_type: system_log_event
        event_data:
          level: WARNING
    actions:
      - action: counter.increment
        target:
          entity_id: counter.warning_counter

Conditional Messages

This automation will create a persistent notification whenever an error or warning is logged that has the word “action” in the message:

automation:
  - alias: "Create notifications for 'action' errors"
    triggers:
      - trigger: event
        event_type: system_log_event
    conditions:
      - condition: template
        value_template: '{{ "action" in trigger.event.data.message[0] }}'
    actions:
      - action: persistent_notification.create
        data:
          title: "Something bad happened"
          message: "{{ trigger.event.data.message[0] }}"

Writing to log

This automation will create a new log entry when the door is opened:

automation:
  - alias: "Log door opened"
    triggers:
      - trigger: state
        entity_id: binary_sensor.door
        from: "off"
        to: "on"
    actions:
      - action: system_log.write
        data:
          message: "Door opened!"
          level: info