Add hacking check for print() statements

We are frequently having to -1 patches because people
forget print() statements that were used for debug in
their development.  Can save everyone time and trouble by
adding this simple hacking check.

The check excluded the cinder/cmd directory as the files in there
legitimately need to use the print() command.  Also wsgi.py and
the test_hds_nas_backend.py files make use of print, so I have
excluded those from checking as well.

Change-Id: I2066eeb2bdc6c9af294d0b9befb7e0b32abd1378

HACKING.rst

@@ -20,6 +20,7 @@ Cinder Specific Commandments
 - [N339] Prevent use of deprecated contextlib.nested.
 - [C301] timeutils.utcnow() from oslo_utils should be used instead of datetime.now().
 - [C302] six.text_type should be used instead of unicode
+- [C303] Ensure that there are no 'print()' statements in code that is being committed.
 
 
 General

cinder/hacking/checks.py

@@ -41,6 +41,7 @@ underscore_import_check = re.compile(r"(.)*i18n\s+import\s+_(.)*")
 # We need this for cases where they have created their own _ function.
 custom_underscore_check = re.compile(r"(.)*_\s*=\s*(.)*")
 no_audit_log = re.compile(r"(.)*LOG\.audit(.)*")
+no_print_statements = re.compile(r"\s*print\s*\(.+\).*")
 
 # NOTE(jsbryant): When other oslo libraries switch over non-namespaced
 # imports, we will need to add them to the regex below.
@@ -207,6 +208,18 @@ def check_unicode_usage(logical_line, noqa):
         yield(0, msg)
 
 
+def check_no_print_statements(logical_line, filename, noqa):
+    # The files in cinder/cmd do need to use 'print()' so
+    # we don't need to check those files.  Other exemptions
+    # should use '# noqa' to avoid failing here.
+    if "cinder/cmd" not in filename and not noqa:
+        if re.match(no_print_statements, logical_line):
+            msg = ("C303: print() should not be used. "
+                   "Please use LOG.[info|error|warning|exception|debug]. "
+                   "If print() must be used, use '# noqa' to skip this check.")
+            yield(0, msg)
+
+
 def factory(register):
     register(no_vi_headers)
     register(no_translate_debug_logs)
@@ -219,3 +232,4 @@ def factory(register):
     register(check_datetime_now)
     register(validate_log_translations)
     register(check_unicode_usage)
+    register(check_no_print_statements)

cinder/tests/test_hacking.py

@@ -209,3 +209,20 @@ class HackingTestCase(test.TestCase):
             "unicode(msg)", False))))
         self.assertEqual(0, len(list(checks.check_unicode_usage(
             "unicode(msg)  # noqa", True))))
+
+    def test_no_print_statements(self):
+        self.assertEqual(0, len(list(checks.check_no_print_statements(
+            "a line with no print statement",
+            "cinder/file.py", False))))
+        self.assertEqual(1, len(list(checks.check_no_print_statements(
+            "print('My print statement')",
+            "cinder/file.py", False))))
+        self.assertEqual(0, len(list(checks.check_no_print_statements(
+            "print('My print statement in cinder/cmd, which is ok.')",
+            "cinder/cmd/file.py", False))))
+        self.assertEqual(0, len(list(checks.check_no_print_statements(
+            "print('My print statement that I just must have.')",
+            "cinder/tests/file.py", True))))
+        self.assertEqual(1, len(list(checks.check_no_print_statements(
+            "print ('My print with space')",
+            "cinder/volume/anotherFile.py", False))))

cinder/tests/test_hds_hnas_backend.py

@@ -263,8 +263,8 @@ UTILS_EXEC_OUT = ["output: test_cmd", ""]
 
 
 def m_run_cmd(*args, **kargs):
-    print(args)
-    print(HNAS_CMDS.get(args))
+    print(args)  # noqa
+    print(HNAS_CMDS.get(args))  # noqa
     return HNAS_CMDS.get(args)
 
 

cinder/wsgi.py

@@ -438,16 +438,16 @@ class Debug(Middleware):
 
     @webob.dec.wsgify(RequestClass=Request)
     def __call__(self, req):
-        print(('*' * 40) + ' REQUEST ENVIRON')
+        print(('*' * 40) + ' REQUEST ENVIRON')  # noqa
         for key, value in req.environ.items():
-            print(key, '=', value)
-        print()
+            print(key, '=', value)  # noqa
+        print()  # noqa
         resp = req.get_response(self.application)
 
-        print(('*' * 40) + ' RESPONSE HEADERS')
+        print(('*' * 40) + ' RESPONSE HEADERS')  # noqa
         for (key, value) in resp.headers.iteritems():
-            print(key, '=', value)
-        print()
+            print(key, '=', value)  # noqa
+        print()  # noqa
 
         resp.app_iter = self.print_generator(resp.app_iter)
 
@@ -456,12 +456,12 @@ class Debug(Middleware):
     @staticmethod
     def print_generator(app_iter):
         """Iterator that prints the contents of a wrapper string."""
-        print(('*' * 40) + ' BODY')
+        print(('*' * 40) + ' BODY')  # noqa
         for part in app_iter:
             sys.stdout.write(part)
             sys.stdout.flush()
             yield part
-        print()
+        print()  # noqa
 
 
 class Router(object):