Revert "Add /label-list to the webapp"

This reverts commit b7378892502836f257456cd277190ee75a7ca75f.

As discussed in [1] the label list is intended to provide a list of
available labels so users don't have to dig into configuration files
to determine what is available to run jobs on.  As written it possibly
misses nodes without a min-ready or in-use nodes, so an alternative
implementation is probably called for.  This is also currently returns
values in a plain list, rather than a list of dicts, which prevents
some de-deuplication refactoring.

Thus remove it for now, pending some more work.

[1] http://lists.zuul-ci.org/pipermail/zuul-discuss/2018-February/000039.html

Change-Id: Ic88da24dd5d140697d4af8e6f5ee0936c44f59c5

nodepool/status.py

@@ -135,22 +135,6 @@ def node_list(zk, node_id=None, detail=False, format='pretty'):
         raise ValueError('Unknown format "%s"' % format)
 
 
-def label_list(zk, format='pretty'):
-    labels = set()
-    for node in zk.nodeIterator():
-        labels.add(node.type)
-    if format == 'pretty':
-        t = PrettyTable(["Label", ])
-        t.align = 'l'
-        for label in labels:
-            t.add_row(label)
-        return str(t)
-    elif format == 'json':
-        return json.dumps(list(labels))
-    else:
-        raise ValueError('Unknown format "%s"' % format)
-
-
 def dib_image_list(zk, format='pretty'):
     headers_table = OrderedDict([
         ("id", "ID"),

nodepool/tests/test_webapp.py

@@ -147,27 +147,6 @@ class TestWebApp(tests.DBTestCase):
         objs = json.loads(data.decode('utf8'))
         self.assertEqual(0, len(objs), objs)
 
-    def test_label_list_json(self):
-        configfile = self.setup_config('node.yaml')
-        pool = self.useNodepool(configfile, watermark_sleep=1)
-        self.useBuilder(configfile)
-        pool.start()
-        webapp = self.useWebApp(pool, port=0)
-        webapp.start()
-        port = webapp.server.socket.getsockname()[1]
-
-        self.waitForImage('fake-provider', 'fake-image')
-        self.waitForNodes('fake-label')
-
-        req = request.Request(
-            "http://localhost:%s/label-list.json" % port)
-        f = request.urlopen(req)
-        self.assertEqual(f.info().get('Content-Type'),
-                         'application/json')
-        data = f.read()
-        objs = json.loads(data.decode('utf8'))
-        self.assertEqual(['fake-label'], objs)
-
     def test_request_list_json(self):
         configfile = self.setup_config('node.yaml')
         pool = self.useNodepool(configfile, watermark_sleep=1)

nodepool/webapp.py

@@ -104,12 +104,6 @@ class WebApp(threading.Thread):
             output = status.node_list(self.nodepool.getZK(),
                                       format='json',
                                       node_id=params.get('node_id'))
-        elif path == '/label-list':
-            output = status.label_list(self.nodepool.getZK(),
-                                       format='pretty')
-        elif path == '/label-list.json':
-            output = status.label_list(self.nodepool.getZK(),
-                                       format='json')
         elif path == '/request-list':
             output = status.request_list(self.nodepool.getZK(),
                                          format='pretty')