triggerd 0.6.0

Trigger an event or notification upon the output of a command.

triggerd is a sysadmin/automation tool used to trigger an event or notification upon the output of a command.

An event file containing the trigger criteria is created. Ideally, you’ll create a cron entry or systemd timer to execute triggerd EVENTFOLDER at a regular interval. If the command status or output matches the trigger criteria, a trigger event or notification is executed and the event file is marked triggered.

triggerd is perfect for querying a webpage for matching text or anything of the sort. I originally created it for use with a modified version of urlwatch to notify me upon certain changes to webpages, however the potential uses are limitless.

The script was originally written as a Bash shell script before it was rewritten in Python. The Bash version is nearly identical and is a great alternative if Python 3 is not available in your environment. It is included in this repository under scripts/triggerd.sh.

Installation

The easiest way to install triggerd is via pip:

pip3 install --user triggerd

FYI: The shell version of triggerd will be installed to your local bin folder as triggerd.sh

Update

Run the following command to update to the most recent version:

pip3 install --upgrade --user triggerd

Usage

triggerd is controlled via configuration files called event files. You can execute it as follows:

triggerd FILE1 FILE2 FILE3...

Or against entire directories of event files:

triggerd EVENTFOLDER1 EVENTFOLDER2...

You can test your event file configuration without actually executing it:

triggerd --verify FILE

The –verbose option can be used to display execution details:

triggerd --verbose FILE

Event Files

Please note: Event files are parsed manually, they are not ‘sourced’ by the shell. Contents are executed by the shell exactly as they appear.

Basic documentation (sample event file and trigger template file) is installed to $PREFIX/share/triggerd/examples

Here is a sample event file that triggers when google.com is not accessible via curl:

COMMAND=curl -sL google.com
EVENT_NAME=Google Availability
MATCH_CONTENT=0
MATCH_CRITERIA=ne
STATUS=enabled
TEST_TYPE=status
TRIGGER_CUSTOM=notify-send --urgency=critical "$EVENT_NAME" "Google is not available!"

Here is a sample event file that triggers when the google.com homepage source code contains the word surprise:

COMMAND=curl -sL google.com
EVENT_NAME=Google Surprise
MATCH_CONTENT=surprise
MATCH_CRITERIA=contains
STATUS=enabled
TEST_TYPE=content
TRIGGER_CUSTOM=notify-send --urgency=critical "$EVENT_NAME" "Google contains a surprise!"

Here is a sample event file that triggers when /tmp is greater than or equal to 10M in size:

COMMAND=du -ms /tmp | cut -f1
EVENT_NAME=Size Check
MATCH_CONTENT=10
MATCH_CRITERIA=ge
STATUS=enabled
TEST_TYPE=arithmetic
TRIGGER_CUSTOM=notify-send --urgency=critical "$EVENT_NAME" "/tmp is >= 10M in size!"

TEST_TYPE options:

arithmetic
content
status    # exit code

MATCH_CRITERIA for arithmetic and status tests:

eq
ge
gt
le
lt
ne

MATCH_CRITERIA for content tests:

contains
does_not_contain

matches
does_not_match

null
not_null

STATUS indicates whether the event is active:

enabled
disabled
triggered    # this will be set by triggerd upon a trigger event

Triggers

There are two types of triggers available.

TRIGGER_CUSTOM is used to indicate a shell command.

i.e. TRIGGER_CUSTOM=notify-send "Trigger Notification"

TRIGGER_NAMED is used to indicate the name of a trigger template.

i.e. TRIGGER_NAMED=special

The trigger templates may be defined in $HOME/.config/triggerd/triggers.conf

ie. special=notify-send --icon=~/.config/triggerd/icons/special.png --urgency=critical "triggerd: $EVENT_NAME" "special event was triggered!"

The event name can be referenced in either trigger as $EVENT_NAME. The same goes for $MATCH_CONTENT.

If no trigger is indicated, a default notification will be displayed via notify-send.

License

Copyright (c) 2015 Six ([e-mail]).

Licensed under the GPLv3 license.