Extend config API with getSupportedLabels()

New config API method to get all labels that are supported by a
configured provider. Used in the launcher to not have to know
what driver is used and the configuration of its config data
structure.

Change-Id: Ib792e84c546bc52507141835ed57bd72ad9f09d3

nodepool/driver/__init__.py

@@ -451,3 +451,10 @@ class ProviderConfig(ConfigValue):
     @abc.abstractmethod
     def getSchema(self):
         pass
+
+    @abc.abstractmethod
+    def getSupportedLabels(self):
+        '''
+        Return a set of label names supported by this provider.
+        '''
+        pass

nodepool/driver/openstack/config.py

@@ -275,3 +275,9 @@ class OpenStackProviderConfig(ProviderConfig):
             'diskimages': [provider_diskimage],
             'cloud-images': [provider_cloud_images],
         })
+
+    def getSupportedLabels(self):
+        labels = set()
+        for pool in self.pools.values():
+            labels.update(pool.labels.keys())
+        return labels

nodepool/driver/static/config.py

@@ -80,3 +80,9 @@ class StaticProviderConfig(ProviderConfig):
             'nodes': [pool_node],
         }
         return v.Schema({'pools': [pool]})
+
+    def getSupportedLabels(self):
+        labels = set()
+        for pool in self.pools.values():
+            labels.update(pool.labels)
+        return labels

nodepool/launcher.py

@@ -288,17 +288,7 @@ class PoolWorker(threading.Thread):
             launcher = zk.Launcher()
             launcher.id = self.launcher_id
             for prov_cfg in self.nodepool.config.providers.values():
-                if prov_cfg.driver.name in ('openstack', 'fake'):
-                    for pool_cfg in prov_cfg.pools.values():
-                        launcher.supported_labels.update(
-                            set(pool_cfg.labels.keys()))
-                elif prov_cfg.driver.name == 'static':
-                    for pool_cfg in prov_cfg.pools.values():
-                        launcher.supported_labels.update(pool_cfg.labels)
-                else:
-                    self.log.error(
-                        "Launcher registration unhandled driver: %s",
-                        prov_cfg.driver.name)
+                launcher.supported_labels.update(prov_cfg.getSupportedLabels())
             self.zk.registerLauncher(launcher)
 
             try:

nodepool/tests/fixtures/drivers/test/config.py

@@ -33,12 +33,14 @@ class TestConfig(ProviderConfig):
 
     def load(self, newconfig):
         self.pools = {}
+        self.labels = set()
         for pool in self.provider.get('pools', []):
             testpool = TestPool()
             testpool.name = pool['name']
             testpool.provider = self
             testpool.max_servers = pool.get('max-servers', math.inf)
             for label in pool['labels']:
+                self.labels.add(label)
                 newconfig.labels[label].pools.append(testpool)
             self.pools[pool['name']] = testpool
 
@@ -46,3 +48,6 @@ class TestConfig(ProviderConfig):
         pool = {'name': str,
                 'labels': [str]}
         return v.Schema({'pools': [pool]})
+
+    def getSupportedLabels(self):
+        return self.labels