jack-matchmaker 0.3.0

Description

jack-matchmaker is a small command line utility that listens to JACK port registrations by clients and connects them when they match one of the port pattern pairs given on the command line at startup. jack-matchmaker never disconnects any ports.

The port name patterns are specified as pairs of positional arguments or read from a file (see below) and are interpreted as Python regular expressions, where the first pattern of a pair is matched against output (readable) ports and the second pattern of a pair is matched against input (writable) ports. Matching is done against the normal port names as well as any aliases they have (run “jack-matchmaker -la” to list all available ports with their aliases).

As many pattern pairs as needed can be given.

Usage

Automatically connect the first two ports of Fluidsynth to the audio outs:

jack-matchmaker "fluidsynth:l_01" "system:playback_1" \
                "fluidsynth:r_01" "system:playback_2"

Both the output port and the input port patterns can be regular expressions. If a match is found on an output port, the matching port will be connected to all input ports, which match the corresponding input port pattern:

jack-matchmaker "fluidsynth:l_\d+" "system:playback_[13]" \
                "fluidsynth:r_\d+" "system:playback_[24]"

You can also use named regular expression groups in the output port pattern and fill the strings they match to into placeholders in the input port pattern:

jack-matchmaker "system:midi_capture_(?P<num>\d+)" \
                "mydaw:midi_in_track_{num}"

Run jack-matchmaker -h (or --help) to show help on the available command line options.

Pattern files

In addition to or instead of from positional arguments on the command line, port patterns can also be read from a file given with the -p/--pattern-file option. The file must list one port pattern per line, where the first line of every pair of two lines specifies the output port pattern, and the second specifies the input port pattern. Empty lines and lines starting with a hash-sign (#) are ignored and whitespace at the start or the end of each line is stripped.

Example file:

# left channel
.*:out_l
    system:playback_1

# right channel
.*:out_r
    system:playback_2

When you send a HUP signal to a running jack-matchmaker process, the file that was specified on the command line when the process was started is re-read and the resulting patterns replace all previously used patterns. If there is an error reading the file, the pattern list will then be empty.

Requirements

• A version of Python 3 with a ctypes module (i.e. PyPy 3 works too).

• JACK version 1 or 2.

• Linux, OS X (untested) or Windows (untested, no signal handling).

Acknowledgements

jack-matchmaker is written in Python and incorporates the jacklib module taken from falkTX’s Cadence application.

It was inspired by jack-autoconnect, which also auto-connects JACK ports, but doesn’t support port aliases. jack-autoconnect is also written in C++, and therefore probably faster and less memory hungry.

The idea to read ports (patterns) from a file and re-read them on the HUP signal was “inspired” by aj-snapshot.