Callback

Each patternfile has the form <digits>-<callback>--<category>.

The callback identifier with the string '-callback' appended forms the name of the callback executable. This executable must be located in ${MULLE_MONITOR_DIR}/bin.

Callback vs. Task

The general expectation is, that a callback is very small and does not take long to execute. A task is something that is longer running and would be running as a background job. In general a callback will only emit a task string and exit.

Callback "API"

The executable will be called with the following arguments and environment

Number	Argument	Description
$1	filepath	The file that has changed
$2	action	One of three possible strings: "create" "modify" "update"
$3	category	The optional category of the matching file

Remember that mulle-monitor callback allows the caller to manually pass any argument he sees fit. mulle-sde uses all empty variables to get a taskname to run its update functionality. The update should be able to incorporate all changes to the filesystem, since the last run of update.

Some environment variables will be available:

Variable	Description
PWD	This variable and the working directory will be the project folder
MULLE_MONITOR_DIR	Location of the .mulle-monitor folder
MULLE_MONITOR_ETC_DIR	Location of the etc folder
MULLE_MONITOR_MATCH_DIR	Location of the match.d folder
MULLE_MONITOR_IGNORE_DIR	Location of the ignore.d folder
MULLE_MONITOR_LIBEXEC_DIR	libexec directory of mulle-monitor
MULLE_BASHFUNCTIONS_LIBEXEC_DIR	libexec directory of mulle-bashfunctions

A very simple callback would be:

#! /bin/sh

# could update a Makefile here maybe

# return task
echo "hello"

You can manage callbacks using the mulle-monitor callback command.

Tips and Tricks

You can pass arguments to the task, by emitting more than just the task name. As the task gets evaled, be sure that your arguments are escaped or quoted properly, so that globbing, expansion and all the other good stuff does not get in the way.

Example:

echo task 'my file with spaces.txt'