limit distRepo tasks per tag

Introduces 'distrepo.cancel_others` extra flag for tags. If enabled, new
distRepo task will cancel previous non-finished ones leaving only new
one.

Fixes: https://pagure.io/koji/issue/1630

cli/koji_cli/commands.py

@@ -6952,8 +6952,14 @@ def handle_regen_repo(options, session, args):
 
 def handle_dist_repo(options, session, args):
     """Create a yum repo with distribution options"""
-    usage = _("usage: %prog dist-repo [options] <tag> <key_id> [<key_id> ...]")
-    parser = OptionParser(usage=get_usage_str(usage))
+    usage = _("usage: %prog dist-repo [options] <tag> <key_id> [<key_id> ...]\n\n"
+              "In normal mode, dist-repo behaves like any other koji task.\n"
+              "Sometimes you want to limit running distRepo tasks per tag to only\n"
+              "one. For such behaviour admin (with 'tag' permission) needs to\n"
+              "modify given tag's extra field 'distrepo.cancel_others' to True'\n"
+              "via 'koji edit-tag -x distrepo.cancel_others=True'\n")
+    usage += _("\n(Specify the --help option for a list of other options)")
+    parser = OptionParser(usage=usage)
     parser.add_option('--allow-missing-signatures', action='store_true',
         default=False,
         help=_('For RPMs not signed with a desired key, fall back to the '

hub/kojihub.py

@@ -11438,6 +11438,20 @@ class RootExports(object):
         context.session.assertPerm('dist-repo')
         repo_id, event_id = dist_repo_init(tag, keys, task_opts)
         task_opts['event'] = event_id
+        # cancel potentially running distRepos
+        tinfo = get_tag(tag, strict=True)
+        if tinfo['extra'].get('distrepo.cancel_others', False):
+            tasks = self.listTasks(opts={
+                                       'state': [koji.TASK_STATES['FREE'],
+                                                 koji.TASK_STATES['OPEN'],
+                                                 koji.TASK_STATES['ASSIGNED']],
+                                       'method': 'distRepo',
+                                       'decode': True})
+            # filter only for this tag
+            task_ids = [t['id'] for t in tasks if t['request'][0] == tag]
+            for task_id in task_ids:
+                logger.debug("Cancelling distRepo task %d" % task_id)
+                Task(task_id).cancel(recurse=True)
         return make_task('distRepo', [tag, repo_id, keys, task_opts], priority=15, channel='createrepo')
 
     def newRepo(self, tag, event=None, src=False, debuginfo=False, separate_src=False):

tests/test_cli/test_dist_repo.py

@@ -45,7 +45,14 @@ class TestDistRepo(utils.CliTestCase):
         self.session.distRepo.return_value = self.task_id
 
         self.error_format = """Usage: %s dist-repo [options] <tag> <key_id> [<key_id> ...]
-(Specify the --help global option for a list of other help options)
+
+In normal mode, dist-repo behaves like any other koji task.
+Sometimes you want to limit running distRepo tasks per tag to only
+one. For such behaviour admin (with 'tag' permission) needs to
+modify given tag's extra field 'distrepo.cancel_others' to True'
+via 'koji edit-tag -x distrepo.cancel_others=True'
+
+(Specify the --help option for a list of other options)
 
 %s: error: {message}
 """ % (self.progname, self.progname)
@@ -249,7 +256,14 @@ class TestDistRepo(utils.CliTestCase):
         self.assert_help(
             handle_dist_repo,
             """Usage: %s dist-repo [options] <tag> <key_id> [<key_id> ...]
-(Specify the --help global option for a list of other help options)
+
+In normal mode, dist-repo behaves like any other koji task.
+Sometimes you want to limit running distRepo tasks per tag to only
+one. For such behaviour admin (with 'tag' permission) needs to
+modify given tag's extra field 'distrepo.cancel_others' to True'
+via 'koji edit-tag -x distrepo.cancel_others=True'
+
+(Specify the --help option for a list of other options)
 
 Options:
   -h, --help            show this help message and exit

tests/test_hub/test_dist_repo.py

@@ -85,15 +85,17 @@ class TestDistRepoInit(unittest.TestCase):
 
 class TestDistRepo(unittest.TestCase):
 
+    @mock.patch('kojihub.get_tag')
     @mock.patch('kojihub.dist_repo_init')
     @mock.patch('kojihub.make_task')
-    def test_DistRepo(self, make_task, dist_repo_init):
+    def test_DistRepo(self, make_task, dist_repo_init, get_tag):
         session = kojihub.context.session = mock.MagicMock()
         # It seems MagicMock will not automatically handle attributes that
         # start with "assert"
         session.assertPerm = mock.MagicMock()
         dist_repo_init.return_value = ('repo_id', 'event_id')
         make_task.return_value = 'task_id'
+        get_tag.return_value = {'extra': {}}
 
         exports = kojihub.RootExports()
         ret = exports.distRepo('tag', 'keys')