Introduction

Simple application that monitors file changes (events) and triggers the execution of a program in response. It is being developed with CI in mind but may be useful for other purposes as well.

Te program is in pre-alpha state but it's functional enough to test itself.

Installation

This program has been tested with python 2.7, 3.4, 3.5, 3.6 and 3.7 but may work with older versions.

pip install arv.autotest

Internals overview

• monitor sets files/directories for changes (pynotify)
• decide what events are processed (event_filters.py). The filters can drop events by type, because the events are coming to fast etc. Throtling is implemented here.
• execute a command in response (runner.py)
• process the output from the command (reporters).
  • display the output on screen
  • display a notification on completion
  • there exist a proof of concept preprocessor that can modify the output (ignore and highlight lines).
  • adjust throtling dynamically

Configuration file

The following example is the configuration file used by autotest to test itself:

{
    "command": "nosetests --verbosity=2",
    "global_ignore": ["\\..*"],
    "watch"  : [
        {
            "path"    : "arv",
            "include" : [".*\\.py"]
        },
        {
            "path"    : "tests",
            "include" : ["test_.*\\.py"]
        }
    ]
}

The command specified in the command key will be executed whenever a change is detected in any of the watched files (the files matching *.py within the arv directory and those matching test_*.py in the tests directory). Files matching any of the global_ignore patterns (hidden files in the example) will be ignored.

In order to determine if an event is processed or ignored:

1. if the file name matches any of the global_ignore regexes the event is ignored. Use this option to ignore temporary files, VCS files etc.
2. the most specific watch is looked for (the one with the longest matching path):
   1. if the file name matches any of the corresponding exclude patterns the event is ignored.
   2. if the file matches any of the include patterns the event is processed.
   3. otherwise it is ignored.

Configuration options

Top level options:

command:	string, required. Command to be executed on every file change.
watch:	a list of watches. See below.
global_ignore:	a list of regexes (strings), optional. If a file name (not path) matches any regex the events related to that file are ignored.
throttling:	See below.
peprocessor:	A list of directives. See below.

Watch options:

path:	string, required. Path of the directory.
recurse:	boolean, default true. If true sub-directories will be monitored recursively.
auto_add:	boolean, default true. If true newly created sub-directories will be automatically monitored.
include:	list of regexes (strings). Regexes matching included files.
exclude:	list of regexes (strings). Regexes matching excluded files.

Preprocessor options:

regex:	regular expression. If the regex matches the whole line the corresponding action i executed.
action:	action identifier. Currently two actions are defined: ignore: remove the line from the output failure: highlight the line in red

Throttling options:

max_events_second:	limit the maximum number of events that will be processed per second.

Notes on regexes

Regexes are re regular expressions, not shell globs. Use .* not *.

Regular expressions are matched against the file name, not the path.

A $ is added to the end of the regexes so test_.*\\.py will match test_foo.py but not test_foo.py.bak. Use test_.*\\.py.* to match both.

Be careful with the slashes, the json loader requires them to be escaped (doubled).

Contact information

Alexis Roda, alexis.roda.villalonga@gmail.com

If you find a bug of have some improvement feel free to drop em an e-mail.