When set to a non-negative value, the script module will call the
configured script every <poll-interval> second.
In this mode, the script is expected to write one tag set and then
exit.
This is intended to simplify the implementation of scripts that would
otherwise just do a loop + sleep.
Closes#67
Assume that a closed pipe means the child died. Even if it hasn’t, we
can’t read anymore from it. We’ll end up killing it anyway before
returning from run().
* Verify int/float/bool values are that, and nothing else
* Verify tag ranges are integers
* Verify a range tag value is inside its range
* Don’t allow anything but false|true for booleans
User is expected to send ‘false’ or ‘true’. But we were parsing the
value using `strtol()`. This caused all bools to be false, since
`strtol()` would always return 0.
This module exec’s a script (or binary), specified by the ‘path’
attribute in the configuration.
It then reads tags from the script’s stdout.
The format of the output is:
tag|type|value
tag|type|value
<empty line>
I.e. the script writes N tags followed by an empty line. This
constitutes a transaction.
When a new transaction is received, its tags replaces *all* previous
tags.
