jack-matchmaker 0.6.0

Auto-connect new JACK ports.

Auto-connect JACK ports as they appear and when they match the port patterns given on the command line or read from a file.

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 -oia” to list all available ports with their aliases).

As many pattern pairs as needed can be given.

Installation

Before you install the software, please refer to the section “Requirements”.

Then simply do:

pip install jack-matchmaker

There is also an AUR package available for Arch Linux users.

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.

JACK server connection

jack-matchmaker needs a connection to a running JACK server to be notified about new ports. On start-up it tries to connect to JACK until a connection can be established or the maximum number of connection attempts is exceeded. This number can be set with the command line option -m/--max-attempts, which defaults to 0, i.e. infinite attempts or until interrupted). jack-matchmaker waits for 3 seconds between each connection attempt by default. Change this interval with the option -I/--connect-interval.

When jack-matchmaker is connected and the JACK server is stopped, the shutdown event is signalled to jack-matchmaker, which the enters the connection loop described above again.

To disconnect from the JACK server and stop jack-matchmaker, press Control-C.

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).

License

jack-matchmaker is licensed under the GNU Public License Version v2.

Please see the file LICENSE for more information.

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.