Cannot launch replica set with auth due to directConnection hack

[p-mongo]

I am trying to launch a replica set with auth:

+ python3 -m mtools.mlaunch.mlaunch --dir /tmpfs/db --binarypath /opt/mongodb/bin --setParameter enableTestCommands=1 --setParameter acceptApiVersion2=1 --setParameter diagnosticDataCollectionEnabled=false --replicaset --name test-rs --nodes 2 --arbiter --auth --username bob --password pwd123
/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py:362: DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead.
  if (LooseVersion(self.current_version) >= LooseVersion("4.2.0")):
/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py:669: DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead.
  if (LooseVersion(self.current_version) >= LooseVersion("3.3.0") or
Generating keyfile: /tmpfs/db/keyfile
launching: "/opt/mongodb/bin/mongod" on port 27017
launching: "/opt/mongodb/bin/mongod" on port 27018
launching: "/opt/mongodb/bin/mongod" on port 27019
replica set 'test-rs' initialized.
waiting for primary to add a user.
Traceback (most recent call last):
  File "/opt/python37/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/opt/python37/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py", line 2226, in <module>
    sys.exit(main())
  File "/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py", line 2222, in main
    tool.run()
  File "/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py", line 620, in run
    getattr(self, self.args['command'])()
  File "/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py", line 826, in init
    if self._wait_for_primary():
  File "/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py", line 1918, in _wait_for_primary
    serverSelectionTimeoutMS=30000)
  File "/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py", line 936, in client
    return MongoConnection(host_and_port, **kwargs)
  File "/opt/python37/lib/python3.7/site-packages/mtools-1.7.1.dev0-py3.7.egg/mtools/mlaunch/mlaunch.py", line 60, in __init__
    Connection.__init__(self, *args, **kwargs)
  File "/opt/python37/lib/python3.7/site-packages/pymongo/mongo_client.py", line 753, in __init__
    _check_options(seeds, opts)
  File "/opt/python37/lib/python3.7/site-packages/pymongo/uri_parser.py", line 391, in _check_options
    raise ConfigurationError("Cannot specify multiple hosts with directConnection=true")
pymongo.errors.ConfigurationError: Cannot specify multiple hosts with directConnection=true
/home/w/apps/ruby-driver/spec/shared/lib/mrss/docker_runner.rb:168:in `run_command': Process exited with code 1 (RuntimeError)
	from /home/w/apps/ruby-driver/spec/shared/lib/mrss/docker_runner.rb:117:in `run_tests'
	from /home/w/apps/ruby-driver/spec/shared/lib/mrss/docker_runner.rb:33:in `run'
	from ./.evergreen/test-on-docker:11:in `<main>'

As far as I can tell what happens is that mlaunch has this hack to add directConnection to MongoClient constructions:

class MongoConnection(Connection):
    """
    MongoConnection class.

    Wrapper around Connection (itself conditionally a MongoClient or
    pymongo.Connection) to specify timeout and directConnection.
    """

    def __init__(self, *args, **kwargs):
        kwargs.setdefault('directConnection', True)
        kwargs.setdefault('serverSelectionTimeoutMS', 1)

        # Set client application name for MongoDB 3.4+ servers
        kwargs['appName'] = f'''mlaunch v{__version__}'''

        Connection.__init__(self, *args, **kwargs)

This hack is employed when waiting for replica set, which passes the list of all hosts to the constructor. Subsequently mlaunch tries to request direct connection to 3 nodes at the same time which pymongo rejects.

Expected behavior

The invocation above to create a replica set with auth.

Actual/current behavior

mlaunch fails to create the deployment.

Steps to reproduce the actual/current behavior

See the command quoted above.

Environment

Software	Version
mtools	master
Python	3.7
MongoDB server	5.0
Operating system	Debian Linux testing

[p-mongo]

Fix:

p-mongodb/mtools-legacy@361fd82
p-mongodb/mtools-legacy@dcebbb0
p-mongodb/mtools-legacy@c8e32c7

[blink1073]

The first two cases are covered by the change in #875, and the third seems unrelated (ismaster = con['admin'].command('isMaster')).