icemac.callonchange 0.6.1

Call a command when a directory or file has changed. (Mac OS only)

icemac.callonchange calls a specific command when a directory or something in it has changed. It was developed to ease test driven development (TDD): it can call the test case under development each time the test case or the developed code changes.

Contents

• Requirements

• General usage

• Usage as script

  • Installation

  • Call as script

• In buildout

  • Installation with default arguments

  • Installation with customized arguments

  • Usage as buildout script

• Stopping callonchange

• Runing the tests

• Thanks

• Similar tools

• Ideas

• Changelog

  • 0.6.1 (2010-12-11)

  • 0.6 (2010-07-28)

  • 0.5 (2010-07-21)

  • 0.4 (2010-07-16)

  • 0.3.2 (2010-07-14)

  • 0.3.1 (2010-07-10)

  • 0.3 (2010-07-07)

  • 0.2 (2010-07-04)

  • 0.1 (2010-07-02)

Requirements

• Mac OS X 10.5+ (Leopard)

• Python 2.4 till 2.7

General usage

Usage: callonchange [options] path utility [utility arguments]

callonchange invokes utility with its utility arguments when path or something in it changes.

Options:

--version

show program’s version number and exit

-h, --help

show this help message and exit

-e EXTENSION

only call utility on changes of a file with this extension (option might be used multiple times)

-q

Do not display any output of callonchange. (Still displays the output of the utility.)

EXTENSION might be specified with or without a leading dot:

-e .py is equal to -e py is equal to -epy

Caution: optional arguments must be specified before the positional arguments (path and utility). Arguments specified after the positional arguments are taken as arguments of the utility.

Usage as script

Installation

To install callonchange as script call:

$ python setup.py install

or install it using a package manager like easy_install or pip.

Call as script

To call it as a script add the path to the directory to be observed and the command (script or program) to be called when the directory or something in it has changed.

Example to call xeyes when a file with the extension log has changed in /var/log enter:

$ callonchange -e log /var/log xeyes

Caution: In this example xeyes is called on every new entry in the log file.

In buildout

There is a recipe in the package which eases installation using buildout.

Installation with default arguments

Add a section to your buildout to generate a script for callonchange (don’t forget to add it to the parts!):

[coc]
recipe = icemac.callonchange

This creates a callonchange script with default arguments. These are:

'-e', 'py', '-e', 'zcml', '-e', 'pt', '-e', 'txt', 'src', 'bin/test', '-cv'

Which means: observe in the src directory files with the extensions py, zcml, pt and txt. Call bin/test with the arguments cv (verbose and color) on changes.

Installation with customized arguments

To override the default arguments add an arguments parameter to the buildout section:

[coc]
recipe = icemac.callonchange
name = coc
arguments = 'Products', 'bin/ztest'

This means: The created script will be named coc. When called it will observe the Products directory and call bin/ztest on changes.

Usage as buildout script

You can add additional parameters when you call the generated script:

$ bin/callonchange -t testObserver

When you use the default arguments in the buildout section, this command line calls bin/test -cv -t testObserver on each change of py, zcml, pt or txt files in the src directory.

Stopping callonchange

To stop a running callonchange instance hit ^C (Control-C).

Runing the tests

To run the tests of icemac.callonchange call:

$ python setup.py test

or use buildout:

$ python bootstrap.py
$ bin/buildout
$ bin/test

or use callonchange itself:

$ python bootstrap.py
$ bin/buildout
$ bin/callonchange

In the last version you have to change something inside the src directory of the package so the observer lets the tests run.

Thanks

Thanks to Malte Borch for the great MacFSEvents which icemac.callonchange is based on.

Similar tools

(Sorted by the time I got to know them.)

• pest: “Auto tester for python” Seems to be designed to run tests and nothing else. Has growl integration. Current version (1.0.3) has no automatic tests.

• sniffer: “An automatic test runner. Supports nose out of the box.” Supports Linux, Windows and Mac OS X. But in current version (0.1.5) Windows is untested. Current version has no automatic tests.

• autonose: “continuous test tracker / runner for nosetests” Seems to focus on nose tests. Version 0.1.5 only acts on changes of python files. Detects file changes not using file system events. So it is slow on larger code bases.

• PyZen: “Continuous testing for paranoid developers.” Seems to be tightly integrated into python’s unittest framework and Django. Detects file changes using comparison of file modification time stamps. So it is slow on larger code bases. Version 0.1 has no automatic tests.

• Flask-Zen: “Flask-Script commands to integrate with PyZen.” Light layer around PyZen to integrate it into Flask. Version 0.1 has no automatic tests.

• nosier: “Monitors paths and upon detecting changes runs the specified command” It is however limited to Linux 2.6 since it depends on the inotify facility. Uses black lists and white lists for files thos changes sould be tracked and has some other nice features. Version 1.1 has no automatic tests.

• supcut: “Simple unobtrusive Python continuous unit testing” It is limited to Linux as it depends on inotify. Expects some of its template files are installed in /usr/share/doc/python-supcut/examples. Although it always talks about running nose tests, it might be used for arbitrary calls, too. Can send e-mails about test run. Version 0.5.1 has no automatic tests.

Ideas

• It would be nice to have predefined argument lines (profiles) even when not using buildout. They could be stored in the home directory of the user. (Should support profiles which reverence other profiles.)

• In buildout recipe: default script name should be section name.

• A minimal time between calls (delay) might be nice, so a change does not result in a call of the utility when it occurred during the delay time.

• The options of callonchange should have long variants, too.

• White list/black list approach of nosier seems to be nice.

• Configurable inital run of the utility would be nice.

• When observing large trees for changes of files with a specific extension, starting up the script can take while as the whole tree has to to be scanned once. During this start up period changes are not yet handled, so a message would be nice when start up is done.

• http://pypi.python.org/pypi/watchdog could be a way to get callonchange running on Linux and Windows, too.

Changelog

0.6.1 (2010-12-11)

• Made tests more robust.

• Added more similar tools to the list.

0.6 (2010-07-28)

• Added compatibility with Python 2.4.

• Now officially supporting Python 2.6 and 2.7, too.

0.5 (2010-07-21)

• Added –version option to callonchange.

• Added another similar tool to the list.

0.4 (2010-07-16)

• When the utility gets called a messge is displayed. This can be omitted by specifying the -q option for callonchange.

• When the utility is not found or another OSError occurred when calling the utility callonchange is now stopped.

0.3.2 (2010-07-14)

• Added list of similar tools.

0.3.1 (2010-07-10)

• Fixed incorrect handling of the find-links buildout parameter.

0.3 (2010-07-07)

• Added abbility to specify file extensions so only files with these extensions will be observed.

• Added a name parameter to the recipe to control the name of the generated script, e. g. allowing more than one icemac.callonchange script in a buildout.

0.2 (2010-07-04)

• Added buildout recipe to ease integration with buildout projects. (See section In buildout.)

0.1 (2010-07-02)

• Initial release.