Control Hubs: Bringing It All Together - Smart Home Automation with Linux and Raspberry Pi - page 261

Every manifest has the same set of driver commands, based in a suitably named directory under
$MINBASE/etc/manifest . These commands are held in files:
onstart : This is an optional script that triggers an introduction to the manifest as a whole.
This could be an initial “here is the news” kind of announcement. The first element of the
manifest should not be played here, however.

onmore : This is another optional script, covering the additional information to be played.
The script should exit with an error code of 1 to terminate the playback.

onnext : This is obligatory and called once at the start to initiate the first piece of
information and repeated for each element in the manifest. Like onmore , it should return an
exit code of 1 to prevent any future results.

onstop : This is called, optionally, at the end of the sequence and usually initiates a chime or
conferment that the manifest has completed. This happens regardless of whether it ended
naturally or by forcible termination.

terminate : This kills any process spawned from an onnext output. It is optional and needed
only for those scripts that launch additional programs, such as the media player that
must invoke mp3player default stop . If this doesn't exist, the process is killed using the
standard Linux command.

N You can connect the music manifest to Cosmic in order to trigger a few random songs at bedtime or read the
news in the morning. There are some fulsome examples of this in the earlier section on routines.

Note

The news manifest is programmed, by default, to read the top headlines from the BBC news site, whereas the
music one will randomly search a given directory and play music it finds there.
Naturally, after a while, the same songs will repeat (such is the nature of pseudo -randomness) that you'll be sick
of hearing them. Therefore, it is a blessing that you can prevent the currently playing song from ever being heard
again with:

manifest default block

or prevent any song from the current tracks' directory (which is useful when only one track exists within it) with:

manifest default blockdir

The details of what is blocked is held in a mirror of your media directory structure inside
/var/log/minerva/manifest/block .

N If a file can be accessed by two different paths, the system only blocks files whose name matches exactly, and
so you might need to reblock files that are symlinked from different locations.

Note

You can review the list of blocked files at any time by either recursively listing the directory, or with the command:

manifest default blocklist