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Find event occurrences across devices

Example: Find which devices have sent a specific event in the last hour​

Scenario

A user notices an event in the Cumulocity UI which related to an error condition. They would like to know how many other devices have also sent this event recently, to know how wide-spread the problem is.

Goal

Get a list of devices where a specific event has been sent to Cumulocity in the last hour.

Procedure

  1. Get the event type of the event that you want to search for.

    In this example we searching for the type device_disconnected.

  1. Find how many events with this type device_disconnected were created in the last 1 hour

    c8y events list --type device_disconnected --dateFrom "-1h" -p 1 --withTotalPages
    Output
    | totalPages | pageSize   | currentPage |
    |------------|------------|-------------|
    | 245        | 1          | 1           |

    The totalPages property on the console show the total number of events found using the search criteria. However some of these events may have come from the same devices.

    To get a list of the unique devices, native commands can be used.

    We will set the pageSize parameter to something higher than the totalPages response, so that we can be sure we have all the result, then we assign the result back to a variable.

    We use the assigned results in $events and use dot notation to reference the .source.id property of every item in the $events array. This result is then piped to the Sort-Object cmdlet which removes

    c8y events list \
        --type device_disconnected \
        --dateFrom "-1h" \
        -p 2000 \
        --select source.id -o csv | sort --unique | wc -l
    Output
    147

    The results show that 147 devices have sent this event in the last hour.

    If you want the ids or names of the devices then just leave out the last pipe | wc -l.

    c8y events list \
        --type device_disconnected \
        --dateFrom "-1h" \
        -p 2000 \
        --select "source.id,source.name" -o csv | sort --unique

    Notes

    • The events API is restricted to a max page size of 2000 events, but you can use the includeAll parameter to fetch all of the results as go-c8y-cli will look after the paging for you.