How to Create a Custom Event for Your Custom Logger

This guide is applicable to the following device / devices:

TMU CM4

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This guide walks you through creating a custom event for your own logger script. This is useful when you want your AutoPi device to react to specific conditions like determining when a trip has started or ended based on your own parameters.

We'll go step-by-step through:

• Creating a custom execution script
• Hooking it into the OBD Manager
• Enabling it on a CAN logger

Step 1: Create a Custom Execution Script

Start by creating a new custom module. In this example, we’ll call it custom_event.

• Navigate to Devices and click on the device you want this change to be applied to.
• Click on Custom Code tab and click "Create".

Here’s what the script looks like:

Here is the code example:

import logging
  
log = logging.getLogger(__name__)
  
def trigger(res):
    if not isinstance(res, dict):
        return 
    for logger_output in res['values']:
        if logger_output['_type'] == "pack_sum_voltage":
            trigger_val = None
            if logger_output["value"] > 400:
                trigger_val = "nominal"
            else:
                trigger_val = "low"
  
            __salt__["minionutil.trigger_event"]("vehicle/hv_battery/voltage/{}".format(trigger_val), data=(dict({"value": logger_output['value']}, **{"_alternating_cache_event_filter.skip": True})))
            log.info("Triggered event {:}".format(trigger_val))
    return None

Explanation

You have created a new function that is called trigger, and it takes one input argument res.

• res is a dictionary passed from the obd.manager.
• The _type attribute of the res dict is the name of the logger we want to react to. Here you can set up some conditionals for 2 different event types:
  • Preferably, limit the event types to limit the amount of indexing elastic_search has to do.
  • The data parameter will usually be the data we react to - which is the value parameter of the logger_output we are looking at.
• We use the alternating_cache_event_filter.skip to ensure that we limit the amount of events, if the events do no change.

Step 2: Add the Script as a Trigger in the OBD Manager

• Navigate to Services tab.
• Select OBD Manager.
• Navigate to the Hooks tab.
• Click Create Hook.
• Fill in the fields:
  • Name: Choose a descriptive name (e.g., event_trigger)
  • Type: Select trigger from the dropdown
  • Function: Use the format custom_event.trigger
  • Enabled: Make sure this toggle is turned on
• Click Save.

Step 3: Assign the Trigger to a Logger

• Navigate to the Workers tab.
• Select the CAN Logger you want to apply the trigger to.
• In the logger settings, find the Trigger dropdown.
• Select your newly created trigger (e.g., event_trigger).
• If your new trigger doesn't appear immediately, try clearing any pending syncs and refreshing the page.

You now have a custom trigger configured for your custom logger. Your AutoPi device will automatically evaluate the logger output and trigger events based on your defined conditions.