Removes eventlet in favor of signal package (#1341)

* Removes eventlet in favor of signal package

Issues:
Fixes #<issueid>

Problem:
The eventlet package was a good first attempt, but seems to have
other issues that plague third party tools.

Analysis:
signal comes with Python and should not have the same issues

Tests:
functional

* Fixes timeout possibly being a string

* Removed traces of eventlet

Author: caphrim007

f5/bigip/__init__.py

@@ -24,16 +24,10 @@
     import urllib.parse as urlparse
 
 try:
-    import eventlet
-
-    # Workaround for bug 401 addressed here
-    # https://github.com/eventlet/eventlet/issues/401#issuecomment-325015989
-    #
-    # This seems to happen on containers often.
-    eventlet.hubs.get_hub()
-    HAS_EVENTLET = True
+    import signal
+    HAS_SIGNAL = True
 except ImportError:
-    HAS_EVENTLET = False
+    HAS_SIGNAL = False
 
 from f5.bigip.cm import Cm
 from f5.bigip.resource import PathElement
@@ -50,6 +44,10 @@
 from f5.sdk_exception import TimeoutError
 
 
+def timeout_handler(signum, frame):
+    raise TimeoutError("Timed out waiting for response")
+
+
 class BaseManagement(PathElement):
     def __init__(self, hostname, username, password, **kwargs):
         self.args = self.parse_arguments(
@@ -115,13 +113,11 @@ def post_configuration_setup(self):
     def _get_tmos_version(self):
         connect = self._meta_data['bigip']._meta_data['icr_session']
         base_uri = self._meta_data['uri'] + 'tm/sys/'
-        if HAS_EVENTLET:
-            eventlet.monkey_patch()
-            try:
-                with eventlet.Timeout(self.args['timeout']):
-                    response = connect.get(base_uri)
-            except eventlet.Timeout:
-                raise TimeoutError("Timed out waiting for response")
+        if HAS_SIGNAL:
+            signal.signal(signal.SIGALRM, timeout_handler)
+            signal.alarm(int(self.args['timeout']))
+            response = connect.get(base_uri)
+            signal.alarm(0)
         else:
             response = connect.get(base_uri)
         ver = response.json()

setup.cfg

@@ -3,5 +3,4 @@ release = 1
 requires = six>=1.9.0
     six<2.0.0
     f5-icontrol-rest>=1.3.0
-    f5-icontrol-rest<2.0.0
-    eventlet>=0.21.0
+    f5-icontrol-rest<2.0.0

setup_requirements.txt

@@ -2,5 +2,4 @@
 six>=1.9.0
 six<2.0.0
 f5-icontrol-rest>=1.3.2
-f5-icontrol-rest<2.0.0
-eventlet>=0.21.0
+f5-icontrol-rest<2.0.0