pulseaudio/audio-playback are difficult to use

[Paul Collins]

In order for a snap to successfully connect to PulseAudio, the following needs to be done:

1) request and connect one of pulseaudio or audio-playback (mentioned for completeness)
2) add ${SNAP}/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/pulseaudio to LD_LIBRARY_PATH
3) point libpulse at the pulseaudio socket, e.g., in a wrapper:

    papath="$XDG_RUNTIME_DIR/../pulse/native"
    if [ ! -e "$papath" ]; then
        echo "Cannot not find '$papath'"
        exit 1
    fi
    export PULSE_SERVER="unix:$papath"

(I got this from tests/lib/snaps/test-snapd-pulseaudio/files/bin/pawrap in the snapd source, which seems to imply this is how it's designed to work.)

Steps 2 and 3 seem like they should be handled by some part of the system, if not necessarily snapd, and not left to the snapper to discover for themselves.

[Zygmunt Krynicki (zyga)]

I can fully confirm this, having gone through the exercise myself this weekend.

[Zygmunt Krynicki (zyga)]

Step 2 is difficult to handle in snapd as it interacts with the organization of files in the snap that traditionally snapd does not interact with.

Step 3 depends on the implementation of pulse on the host, though I agree this is the correct solution, for now, and that it should *not* be handled by snap packages but by a layer inside snapd.