Because it doesn't make sense to replace the date placeholder at
process creation, it has to be replaced at every start of the process.
On process creation only the static placeholders (such as process ID)
are replaced. Dynamic placeholders (so far only "date") are not
replaced. On process start, a callback has been introduced that gives
the chance to change the command line. This is the point where
the restreamer replaces the date placeholders.
1. Allow variables in placeholders for parameter values, e.g.
{rtmp,name=$processid}. The variable starts with a $ letter.
The recognized variables are provided with the Replace func.
2. The template func recieves the process config and the name of
the section where this placeholder is located, i.e. "global",
"input", or "output".
If a process has some cleanup with purge-on-delete defined, the purge
has to wait until the process actually exited. Otherwise it may happen
that the process got the signal, files are purged, but the process is
still writing some files in order to exit cleanly. This would lead to
some artefacts left on the filesystem.
For the API endpoint /v3/process two new query parameter are introduced
in order to list only processes that match a pattern for the id and the
reference: idpattern and refpattern. The pattern is a glob pattern. If
patterns for both are given, the results will be intersected. If you use
other query parameters such as id or reference, they will be applied
after the result of the pattern matching.
If a value for a placeholder needs escaping, add the character to
escape with an "^" to the name of the placeholder, e.g. {memfs^:}.
This will escape all occurences of ":" in the value for {memfs}
with a "\".
If PUT /process/:id is called in order to replace an existing
process config with an invalid process config, the existing
process was deleted and an 409 was returned. A subsequent GET on
the previous process would then return a 404, which is not
what you expect. The previous process needs to stay in place.
