Add pylint wrapper

Add run_pylint.py that probe working directory for python source files
and pass them to pylint. This is needed because pylint expects module
or package, so passing a directory with no __init__.py in it makes
pylint angry. With this change, LSR_PYLINT_DIRS is no longer needed.

Additionally, we no longer need:
- init-hook in pylintrc
- [pylintrc] section in tox.ini, because the configuration from this
  section is now the part of pylintrc
- [pycodestyle] section in tox.ini, because pycodestyle linter is not
  used

.travis/config.sh

@@ -1,4 +1,3 @@
-export LSR_PYLINT_DIRS='library/network_connections.py module_utils/network_lsr tests/unit/test_network_connections.py'
 export LSR_MOLECULE_DEPS='-rmolecule_requirements.txt'
 
 case "x${TRAVIS_PYTHON_VERSION}" in

pylintrc

@@ -16,8 +16,7 @@ ignore-patterns=
 
 # Python code to execute, usually for sys.path manipulation such as
 # pygtk.require().
-init-hook="from pylint.config import find_pylintrc; import os, sys; sys.path.append(os.path.dirname(find_pylintrc()) + '/library'); sys.path.append(os.path.dirname(find_pylintrc()) + '/module_utils'); sys.path.append(os.path.dirname(find_pylintrc()) + '/tests')"
-
+#init-hook=
 
 # Use multiple processes to speed up Pylint.
 jobs=1
@@ -56,7 +55,7 @@ confidence=
 # --enable=similarities". If you want to run only the classes checker, but have
 # no Warning level messages displayed, use"--disable=all --enable=classes
 # --disable=W"
-disable=
+disable=wrong-import-position
 #disable=print-statement,
 #        parameter-unpacking,
 #        unpacking-in-except,
@@ -246,7 +245,7 @@ indent-after-paren=4
 indent-string='    '
 
 # Maximum number of characters on a single line.
-max-line-length=100
+max-line-length=88
 
 # Maximum number of lines in a module
 max-module-lines=1000

run_pylint.py

@@ -0,0 +1,144 @@
+#                                                         -*- coding: utf-8 -*-
+# Probe directory tree for python files and pass them to pylint
+# Copyright (C) 2019  Red Hat, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+"""
+Usage: python run_pylint.py ARGUMENTS
+
+Run pylint with ARGUMENTS followed by the list of python files contained in the
+working directory and its subdirectories.  As a python file is recognized a
+file that match the regular expression .*\\.py[iw]?$.  Files and directories
+that match the regular expression ^\\..* are skipped.  Symbolic links are also
+skipped.
+
+There are several cases when argument from ARGUMENTS is not passed to pylint
+but it is handled by run_pylint.py instead:
+
+  1. if -h or --help is contained in ARGUMENTS, this help screen is printed to
+     the standard output and run_pylint.py exits with 0;
+  2. if --include followed by a PATTERN is contained in ARGUMENTS, the PATTERN
+     is used to recognize whether the file is a python file or not, instead of
+     default .*\\.py[iw]?$;
+  3. if --exclude followed by a PATTERN is contained in ARGUMENTS, the PATTERN
+     is used to recognize whether the file or directory should be skipped (i.e.
+     instead of default ^\\..*, the PATTERN is used).
+
+Exclusion takes a priority over inclusion, i.e. if a file or directory can be
+both included and excluded, it is excluded.
+"""
+
+import os
+import re
+import sys
+
+from colorama import Fore
+from pylint.lint import Run
+
+
+def blue(s):
+    """
+    Return string `s` colorized to blue.
+    """
+
+    return "%s%s%s" % (Fore.BLUE, s, Fore.RESET)
+
+
+def print_line(s):
+    """
+    Write `s` followed by the line feed character to the standard output.
+    """
+
+    sys.stdout.write("%s\n" % s)
+
+
+def probe_args():
+    """
+    Analyze the command line arguments and return a tuple containing a list of
+    pylint arguments, pattern string to recognize files to be included, and
+    pattern string to recognize files and directories to be skipped.
+    """
+
+    args = []
+    include_pattern = r".*\.py[iw]?$"
+    exclude_pattern = r"^\..*"
+    i, nargs = 1, len(sys.argv)
+    while i < nargs:
+        arg = sys.argv[i]
+        if arg == "--include":
+            i += 1
+            assert i < nargs, "--include: missing PATTERN"
+            include_pattern = sys.argv[i]
+        elif arg == "--exclude":
+            i += 1
+            assert i < nargs, "--exclude: missing PATTERN"
+            exclude_pattern = sys.argv[i]
+        else:
+            args.append(arg)
+        i += 1
+    return args, include_pattern, exclude_pattern
+
+
+def probe_dir(path, include_re, exclude_re):
+    """
+    Recursively go through directory structure starting at `path`, collect
+    files that match `include_re`, skip files and directories that are either
+    symbolic links or match `exclude_re`. Return the list of collected files.
+    """
+
+    files = []
+    for direntry in os.listdir(path):
+        fullpath = os.path.join(path, direntry)
+        if os.path.islink(fullpath) or exclude_re.match(direntry):
+            continue
+        elif os.path.isdir(fullpath):
+            files.extend(probe_dir(fullpath, include_re, exclude_re))
+        elif os.path.isfile(fullpath) and include_re.match(direntry):
+            files.append(fullpath)
+    return files
+
+
+def show_files(files):
+    """
+    Print `files` to the standard output, one item per line, in a blue color.
+    """
+
+    if not files:
+        return
+    print_line(blue("%s: files to be checked:" % sys.argv[0]))
+    for f in files:
+        print_line(blue("    %s" % f))
+
+
+def main():
+    """
+    Script entry point. Return exit code.
+    """
+
+    args, include_pattern, exclude_pattern = probe_args()
+    if "-h" in args or "--help" in args:
+        sys.stdout.write(__doc__)
+        return 0
+    files = probe_dir(
+        os.getcwd(), re.compile(include_pattern), re.compile(exclude_pattern)
+    )
+    show_files(files)
+    args.extend(files)
+    sys.argv[0] = "pylint"
+    return Run(args, None, False).linter.msg_status
+
+
+if __name__ == "__main__":
+    sys.exit(main())

tox.ini

@@ -106,23 +106,16 @@ deps =
 commands =
     black --check --diff --include "^[^.].*\.py$" --exclude "/(\.[^.].*|tests/roles)/" .
 
-# Custom role settings may set LSR_PYLINT_DIRS environment variable if there is
-# a reason to have other than default directories (library/ module_utils/ and
-# tests/). For example, network role should have this set like
-#
-#   LSR_PYLINT_DIRS="library/network_connections.py module_utils/network_lsr tests/unit/test_network_connections.py"
-#
 [testenv:pylint]
 basepython = python2.7
 setenv =
     {[base]setenv}
 deps =
+    colorama
     pylint>=1.8.4
     ansible
 commands =
-    pylint --errors-only \
-           {posargs} \
-           {env:LSR_PYLINT_DIRS:library module_utils tests}
+    {envpython} ./run_pylint.py --errors-only {posargs}
 
 [testenv:flake8]
 basepython = python2.7
@@ -223,13 +216,6 @@ show_source = true
 max-line-length = 88
 ignore = E402,W503
 
-[pylint]
-max-line-length = 88
-disable = wrong-import-position
-
-[pycodestyle]
-max-line-length = 88
-
 [travis]
 python =
   2.6: py26,extra