Installation

whenever does not really need an installation: the binary files that result from the build process are self-contained, and only need to be moved in a directory mentioned in the PATH environment variable, or just to be directly invoked using the full path to the executable.

Running whenever from the command line, though, is not really useful – if not in order to test a configuration file, especially if it has not been produced by means of a configuration utility such as When. The tool, in fact, is designed to be launched by a GUI application, to hide the console window and to issue appropriate commands to control the scheduler execution.

There are two frontend applications available for whenever: the former is minimal, takes only about 4MB of RAM while running, and does little more than executing the scheduler in background and giving the user the possibility to stop it gracefully. The latter is a full-featured frontend, that manages the scheduler configuration, runs it in the background, provides user interaction with it, and exploits some of the advanced features of whenever to provide a more effective interface and some specific configuration items (tasks, conditions and events) for the platform it is running on.

Minimal Frontend

The minimal frontend is whenever_tray: the installation procedure is manual, and can be fulfilled following these steps:

on Windows there are no prerequisites, so this step can be skipped. On Linux, some libraries might be needed:
- wxGTK 3.2 (or later): they should be available most of the times via the system package manager, sometimes by adding a third party repository
- libxss and libX11, which normally come by installing Xorg support.
Also, enable app indicators if needed, using an appropriate shell extension.
Download the latest binaries ZIP file from the whenever releases page (the provided one contains both whenever and whenever_tray) and extract its contents in a directory in the system PATH.
Create the application data directory for whenever_tray as follows:
- on Linux: mkdir ~/.whenever
- on Windows: mkdir %APPDATA%\Whenever

Edit whenever.toml in the application data directory, so that it contains the following TOML configuration:

# whenever configuration file
scheduler_tick_seconds = 5
randomize_checks_within_ticks = true

[[task]]
type = "lua"
name = "TRACE"
script = '''
    log.warn("Trace: *** VERIFIED CONDITION *** `" .. whenever_condition .. "`");
    '''

[[condition]]
name = "Periodic00"
type = "interval"
interval_seconds = 60
recurring = true
tasks = [
    "TRACE",
    ]

# end.

in the same application data directory, also create the whenever_tray.toml file, so that it contains what follows:
```
[whenever_tray]
# path to the text processor used to view the log file
#logview_command = 'gnome-text-editor'
#logview_command = 'gedit'
#logview_command = 'notepad.exe'
```
just uncommenting the appropriate line for a log viewer available on the platform.
Launch whenever_tray, for example from the command line
Access whenever from the metronome icon in the notification/tray area.

The whenever.toml configuration file should be edited to suit your needs, as the provided example only logs a line (with WARN severity) every minute. Also, you might want to install a log viewer application to specify as logview_command in whenever_tray.toml, instead of using generic editor like the ones shown in the example above: for instance, glogg has been very useful in my case on both Linux and Windows.

Complete Frontend

At the moment the easiest way to install whenever and start using it effectively is through its full-featured frontend: When. You can follow its specific installation instructions here: When takes care of downloading and checking the latest binary release of whenever, and provides a way to install the program icons and to autostart the scheduler upon login. Moreover, When offers a graphical UI to configure tasks, conditions, and events, instead of manually editing the configuration file.