Fix shell hangs on checkconfig command when using http steps

master/buildbot/steps/http.py

@@ -65,11 +65,11 @@ class HTTPStep(BuildStep):
                       "timeout", "allow_redirects", "proxies",
                       "hooks", "stream", "verify", "cert"]
     renderables = requestsParams
+    session = None
 
     def __init__(self, url, method, description=None, descriptionDone=None, **kwargs):
         if txrequests is None or requests is None:
             config.error("Need to install txrequest to use this step:\n\n pip install txrequests")
-        self.session = getSession()
         self.method = method
         self.url = url
         self.requestkwargs = {'method': method, 'url': url}
@@ -91,7 +91,11 @@ def start(self):
 
     @defer.inlineCallbacks
     def doRequest(self):
+        # create a new session if it doesn't exist
+        self.session = getSession()
+
         log = self.addLog('log')
+
         # known methods already tested in __init__
 
         log.addHeader('Performing %s request to %s\n' % (self.method, self.url))