Enable developers to see pylint output

The program tools/lintstack.py which is executed by
tools/lintstack.sh when Jenkins runs, only tests for differences
in the output of pylint. Right now, there seems to be
17 errors/warnings that are being carried over from fix to fix,
with no difference between fixes, and so no failures in the
pylint Jenkins job.

It is really difficult to tell what the errors are, so this fix
allows developers determine what the errors are by running the
following command:

$ tox -e lint

A sample output of the command is available as an attachment
to the bug.

Change-Id: I88487829576d55d437b934e08571013b7a6e57cf
Signed-off-by: Luis Pabón <lpabon@redhat.com>
Closes-Bug: #1356588
Signed-off-by: Luis Pabón <lpabon@redhat.com>

tools/lintstack.py

@@ -151,6 +151,25 @@ def generate_error_keys(msg=None):
         ErrorKeys.print_json(errors, output=f)
 
 
+def check():
+    print("Running pylint. Be patient...")
+    newmsg = run_pylint()
+    errors = LintOutput.from_msg_to_dict(newmsg)
+
+    passed = True
+    for err_key, err_list in errors.items():
+        for err in err_list:
+            print(err.review_str() + "\n")
+            passed = False
+
+    if passed:
+        print("Congrats! pylint check passed.")
+    else:
+        print("\nPlease fix the errors above. If you believe they are false "
+              "positives, run 'tools/lintstack.py generate' to overwrite.")
+        sys.exit(1)
+
+
 def validate(newmsg=None):
     print("Loading", KNOWN_PYLINT_EXCEPTIONS_FILE)
     known = ErrorKeys.from_file(KNOWN_PYLINT_EXCEPTIONS_FILE)
@@ -197,6 +216,8 @@ def main():
         generate_error_keys()
     elif option == "validate":
         validate()
+    elif option == "check":
+        check()
     else:
         usage()
 

tox.ini

@@ -50,6 +50,11 @@ deps = -r{toxinidir}/requirements.txt
 whitelist_externals = bash
 commands = bash tools/lintstack.sh
 
+[testenv:lint]
+deps = -r{toxinidir}/requirements.txt
+       pylint==0.26.0
+commands = python tools/lintstack.py check
+
 [flake8]
 # Following checks are ignored on purpose:
 #