Prefetch all MRs of each project, then filter

lhcbnightlyconf/_gitlab.py

@@ -65,24 +65,26 @@ def getMRCommit(project_id, mr_iid):
 
 
 @cached
+def _getAllProjectMRs(project_id):
+    return _getGitlabProject(project_id).mergerequests.list(
+        state='opened', all=True)
+
+
 def getMergeRequests(project_id, labels=None, wip=None, target_branch=None):
     from gitlab import GitlabGetError
-
+    wip_condition = (lambda _: True) if wip is None else (
+        lambda mr: mr.work_in_progress == wip)
+    label_condition = (lambda _: True) if not labels else ()
+    if labels:
+        labels = set(labels)
+        label_condition = lambda (mr): labels.intersection(mr.labels)
+    else:
+        label_condition = lambda _: True
+    condition = lambda mr: (mr.target_branch == target_branch and wip_condition(mr) and label_condition(mr))
     try:
-        project = _getGitlabProject(project_id)
         return sorted((mr.iid, getMRCommit(project_id, mr.iid))
-                      for mr in project.mergerequests.list(
-                          state='opened',
-                          all=True,
-                          target_branch=target_branch,
-                          labels=labels,
-                          wip={
-                              True: 'yes',
-                              False: 'no'
-                          }.get(wip, wip)))
-
-    except (ImportError, KeyError):
-        pass
+                      for mr in _getAllProjectMRs(project_id) if condition(mr))
+
     except GitlabGetError:
         _logger.warning('problem getting MRs for %s', project_id)
         return []