SyntaxError: invalid syntax when running supervisor-stdout plugin on Python 3.8

[kristijorgji]

The problem

I installed supervisor using pip like:

pip install supervisor supervisor-stdout

Installation was succesful. Then trying to open supervisord crashes:

ubuntu:~$ supervisord
Traceback (most recent call last):
  File "/usr/local/bin/supervisord", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.8/dist-packages/supervisor/supervisord.py", line 352, in main
    options.realize(args, doc=__doc__)
  File "/usr/local/lib/python3.8/dist-packages/supervisor/options.py", line 485, in realize
    Options.realize(self, *arg, **kw)
  File "/usr/local/lib/python3.8/dist-packages/supervisor/options.py", line 310, in realize
    self.process_config()
  File "/usr/local/lib/python3.8/dist-packages/supervisor/options.py", line 549, in process_config
    Options.process_config(self, do_usage=do_usage)
  File "/usr/local/lib/python3.8/dist-packages/supervisor/options.py", line 318, in process_config
    self.process_config_file(do_usage)
  File "/usr/local/lib/python3.8/dist-packages/supervisor/options.py", line 348, in process_config_file
    self.read_config(self.configfile)
  File "/usr/local/lib/python3.8/dist-packages/supervisor/options.py", line 671, in read_config
    section.process_group_configs = self.process_groups_from_parser(parser)
  File "/usr/local/lib/python3.8/dist-packages/supervisor/options.py", line 752, in process_groups_from_parser
    result_handler = self.import_spec(result_handler)
  File "/usr/local/lib/python3.8/dist-packages/supervisor/options.py", line 393, in import_spec
    return ep.resolve()
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 2451, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/usr/local/lib/python3.8/dist-packages/supervisor_stdout.py", line 22
    print '%s %s | %s'%(headers['processname'], headers['channel'], data),
          ^
SyntaxError: invalid syntax

My setup and versions

Ubuntu 20.04

pip --version
pip 20.0.2 from /usr/lib/python3/dist-packages/pip (python 3.8)

ubuntu:~$ python3 --version
Python 3.8.5

[mnaberez]

pip install supervisor supervisor-stdout

...

File "/usr/local/lib/python3.8/dist-packages/supervisor_stdout.py", line 22
   print '%s %s | %s'%(headers['processname'], headers['channel'], data),
         ^
SyntaxError: invalid syntax

The SyntaxError above occurs when the supervisord-stdout plugin is run. This is a third party plugin that is not part of the main Supervisor project. Please report this issue to the authors of that plugin.

[mnaberez]

Moved to: coderanger/supervisor-stdout#21