lottie errors out on start

[computeronix]

Describe the bug
during startup i receive the following error

[0000] INFO main: Running version 1.22.1 b979aff
2021/05/18 03:28:04 Telegram bridge configured to convert .tgs files to 'png', but lottie does not appear to work:
&exec.ExitError{ProcessState:(*os.ProcessState)(0xc00001e648), Stderr:[]uint8(nil)}

To Reproduce
Steps to reproduce the behavior:
In Azure, setup an Ubuntu 18.04.5 LTS VM
Download latest version of matterbridge
setup matterbridge config to include
MediaConvertWebPToPNG=true
MediaConvertTgs="png"

Install dependencies: pip3 install lottie cairosvg

Expected behavior
Matterbridge should run after above dependencies have been installed

Screenshots/debug logs
Environment (please complete the following information):

• OS: Ubuntu 18.04.5 LTS (GNU/Linux 5.4.0-1047-azure x86_64)
• Matterbridge version: 1.22.1 b979aff

[42wim]

Is the lottie_convert.py script reachable in the PATH matterbridge is using?
Try lottie_convert.py --help

[computeronix]

Thank you so much for this as this helped point me in the right direction.

When I ran

lottie_convert.py --help

I received:

Traceback (most recent call last):
File "/usr/local/bin/lottie_convert.py", line 11, in
from lottie.exporters import exporters
File "/usr/local/lib/python3.9/dist-packages/lottie/init.py", line 3, in < module>
from . import objects, parsers, utils, exporters, nvector, importers
File "/usr/local/lib/python3.9/dist-packages/lottie/exporters/init.py", li ne 16, in
from . import cairo, gif
File "/usr/local/lib/python3.9/dist-packages/lottie/exporters/cairo.py", line 1, in
import cairosvg
File "/usr/local/lib/python3.9/dist-packages/cairosvg/init.py", line 26, i n
from . import surface # noqa isort:skip
File "/usr/local/lib/python3.9/dist-packages/cairosvg/surface.py", line 9, in
import cairocffi as cairo
File "/usr/local/lib/python3.9/dist-packages/cairocffi/init.py", line 48, in
cairo = dlopen(
File "/usr/local/lib/python3.9/dist-packages/cairocffi/init.py", line 45, in dlopen
raise OSError(error_message) # pragma: no cover
OSError: no library called "cairo" was found
no library called "libcairo-2" was found
cannot load library 'libcairo.so.2': libcairo.so.2: cannot open shared object fi le: No such file or directory
cannot load library 'libcairo.2.dylib': libcairo.2.dylib: cannot open shared obj ect file: No such file or directory
cannot load library 'libcairo-2.dll': libcairo-2.dll: cannot open shared object file: No such file or directory

Digging into this message, I found the following package was needed to be installed:

sudo apt-get install libcairo2-dev

Ubuntu 20.04 and above
sudo apt install libpangocairo-1.0-0

Now the lottie_convert.py --help returns the help menu.

Next I attempted to run matterbridge and it ran successfully with the parameters for Web PNG and then converted the stickers properly.

I would recommend adding this to #1173 as part of a recommendation if users run into this.

Thank you!