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Events

Get counts of events in one hour intervals for the last 12 hours​

caution

The shell example requires gnu parallel to be installed

# Required: gnu parallel
seq 0 11 | parallel -j1 --env --tags \
    c8y events list \
        --type device_connected \
        --dateFrom "-{}h" \
        --dateTo \"'-$(( {} - 1 ))h'\" \
        --withTotalPages \
        --pageSize 1 \
        --select self,statistics.totalPages \
        --output csv
Output
https://{tenant}/event/events?dateTo=2021-04-21T19:42:50.367513487%2B02:00&pageSize=1&dateFrom=2021-04-21T17:42:50.367508287%2B02:00&type=device_connected&currentPage=1&withTotalPages=true,0
https://{tenant}/event/events?dateTo=2021-04-21T17:42:50.629192387%2B02:00&pageSize=1&dateFrom=2021-04-21T15:42:50.629187187%2B02:00&type=device_connected&currentPage=1&withTotalPages=true,0
https://{tenant}/event/events?dateTo=2021-04-21T15:42:50.888966887%2B02:00&pageSize=1&dateFrom=2021-04-21T13:42:50.888961787%2B02:00&type=device_connected&currentPage=1&withTotalPages=true,0
https://{tenant}/event/events?dateTo=2021-04-21T13:42:51.100022987%2B02:00&pageSize=1&dateFrom=2021-04-21T11:42:51.100018187%2B02:00&type=device_connected&currentPage=1&withTotalPages=true,0
https://{tenant}/event/events?dateTo=2021-04-21T11:42:51.267113687%2B02:00&pageSize=1&dateFrom=2021-04-21T09:42:51.267106787%2B02:00&type=device_connected&currentPage=1&withTotalPages=true,0
https://{tenant}/event/events?dateTo=2021-04-21T09:42:51.453355987%2B02:00&pageSize=1&dateFrom=2021-04-21T07:42:51.453350587%2B02:00&type=device_connected&currentPage=1&withTotalPages=true,0

Explanation (shell)​

seq can is used to here to create to generate the relative dateFrom parameters. seq 2 2 12 means to create a sequence of number start from 2 and stop at 12, but go in increments of 2. So running just the seq command gives the following output.

2
4
6
8
10
12

The output of the seq command is then piped into another useful utility parallel which takes input from standard input and passes it to the given command using the --tags parameter. Each piped input line is available for use by referencing the string {}. In this case {} is used for setting the dateFrom and dateTo.

dateTo is a little more complicated as it needs to do a small addition before it can be used as a relative date. $(( <line_value> + 2 )) is sh/bash/zsh syntax for performing arithmetic.

Technically xargs could also be used, however it is much more restrictive when it comes to handling special characters etc.

Below how the command will be executed by parallel. The additional parameters i.e. withTotalPages have been left out so it is easier to read.

c8y events list --type device_connected --dateFrom "-2h" --dateTo "-0h" 
c8y events list --type device_connected --dateFrom "-4h" --dateTo "-2h" 
c8y events list --type device_connected --dateFrom "-6h" --dateTo "-4h" 
c8y events list --type device_connected --dateFrom "-8h" --dateTo "-6h" 
c8y events list --type device_connected --dateFrom "-10h" --dateTo "-8h" 
c8y events list --type device_connected --dateFrom "-12h" --dateTo "-10h"