Fix Pylint plugin not found error and some lingering Pylint warnings

Signed-off-by: Jean Snyman <git@jsnyman.com>

.github/workflows/test.yml

@@ -40,7 +40,7 @@ jobs:
     - name: Install build dependencies
       run: sudo dnf -y install swig
     - name: Install Python dependencies
-      run: sudo dnf -y install python3.6 tox python3-pip python3-gpg
+      run: sudo dnf -y install python3.6 tox python3-pip
     - name: Run lints
       run: tox -vv -e 'pylint'
     - name: Run mypy

keylime/cmd/verifier.py

@@ -1,14 +1,7 @@
-import asyncio
-
-import tornado.process
-
 from keylime import cloud_verifier_tornado, config, keylime_logging
 from keylime.common.migrations import apply
 from keylime.mba import mba
 
-# from keylime.web import VerifierServer
-from keylime.models.base import db_manager
-
 logger = keylime_logging.init_logging("verifier")
 
 
@@ -19,16 +12,8 @@ def main() -> None:
 
     # Explicitly load and initialize measured boot components
     mba.load_imports()
-
-    # TODO: Replace call with cloud_verifier_tornado.main() with code below (commented out)
     cloud_verifier_tornado.main()
 
-    # db_manager.make_engine("cloud_verifier")
-
-    # server = VerifierServer()
-    # tornado.process.fork_processes(0)
-    # asyncio.run(server.start())
-
 
 if __name__ == "__main__":
     try:

keylime/models/__init__.py

@@ -1,5 +1,15 @@
-from keylime.models.base.da import da_manager
-from keylime.models.base.db import db_manager
-from keylime.models.registrar import *
+# Checks whether script is being invoked by tox in a virtual environment
+def is_tox_env():
+    # Import 'os' inside function to avoid polluting the namespace of any module which imports 'keylime.models'
+    import os  # pylint: disable=import-outside-toplevel
 
-# from keylime.models.verifier import *
+    return bool(os.environ.get("TOX_ENV_NAME"))
+
+
+# Only perform automatic imports of submodules if tox is not being used to perform static checks. This is necessary as
+# models like RegistrarAgent indirectly import package 'gpg' which is not available in a tox environment as it is
+# installed via the system package manager
+if not is_tox_env():
+    from keylime.models.base.da import da_manager
+    from keylime.models.base.db import db_manager
+    from keylime.models.registrar import *

scripts/check_codestyle.sh

@@ -11,11 +11,6 @@ if [ -z "$(type -P ${PYLINT})" ]; then
 	exit 1
 fi
 
-# Allow python to find gpg package installed with system package manager
-PYTHONPATH=$(python3 -c 'import sys; print(":".join(sys.path))')
-PYTHONPATH="$PYTHONPATH:/usr/lib/python3/dist-packages"
-export PYTHONPATH
-
 ${PYLINT} --version
 
 ${PYLINT} \