Partial revert for disabled provider change

Commit 1cf2cddf9d attempted to
short-circuit request handling when a provider was disabled by
setting max-servers to 0. That prevents the provider from declining
any requests, and thus prevents a request from ever reaching
FAILURE status if none of the other providers can satisfy it (the
request declined_by array is compared against the list of registered
launchers).

This adds a test for this case (which was run against the current
code and proved it was broken).

Change-Id: I8a2f9771b55b08259ecffa3475bdd2d4f2654464

nodepool/launcher.py

@@ -157,13 +157,11 @@ class PoolWorker(threading.Thread):
         the handler for completion.
         '''
         provider = self.getProviderConfig()
-        if not provider or (self.pool_name not in provider.pools):
+        if not provider:
             self.log.info("Missing config. Deleted provider?")
             return
 
-        pool_config = provider.pools[self.pool_name]
-
-        if provider.max_concurrency == 0 or pool_config.max_servers <= 0:
+        if provider.max_concurrency == 0:
             return
 
         for req_id in self.zk.getNodeRequests():

nodepool/tests/fixtures/disabled_provider.yaml

@@ -0,0 +1,47 @@
+elements-dir: .
+images-dir: '{images_dir}'
+
+zookeeper-servers:
+  - host: {zookeeper_host}
+    port: {zookeeper_port}
+    chroot: {zookeeper_chroot}
+
+labels:
+  - name: fake-label
+    min-ready: 1
+
+providers:
+  - name: fake-provider
+    cloud: fake
+    driver: fake
+    region-name: fake-region
+    rate: 0.0001
+    diskimages:
+      - name: fake-image
+        meta:
+          key: value
+          key2: value
+    pools:
+      - name: main
+        max-servers: 0
+        availability-zones:
+          - az1
+        networks:
+          - net-name
+        labels:
+          - name: fake-label
+            diskimage: fake-image
+            min-ram: 8192
+            flavor-name: 'Fake'
+
+diskimages:
+  - name: fake-image
+    elements:
+      - fedora
+      - vm
+    release: 21
+    env-vars:
+      TMPDIR: /opt/dib_tmp
+      DIB_IMAGE_CACHE: /opt/dib_cache
+      DIB_CLOUD_IMAGES: http://download.fedoraproject.org/pub/fedora/linux/releases/test/21-Beta/Cloud/Images/x86_64/
+      BASE_IMAGE_FILE: Fedora-Cloud-Base-20141029-21_Beta.x86_64.qcow2

nodepool/tests/test_launcher.py

@@ -1013,3 +1013,24 @@ class TestLauncher(tests.DBTestCase):
         self.assertEqual(req.state, zk.FULFILLED)
         self.assertEqual(1, len(req.declined_by))
         self.assertIn('fake-provider-main', req.declined_by[0])
+
+    def test_disabled_provider(self):
+        '''
+        A request should fail even with a provider that is disabled by
+        setting max-servers to 0. Because we look to see that all providers
+        decline a request by comparing the declined_by request attribute to
+        the list of registered launchers, this means that each must attempt
+        to handle it at least once, and thus decline it.
+        '''
+        configfile = self.setup_config('disabled_provider.yaml')
+        self.useBuilder(configfile)
+        pool = self.useNodepool(configfile, watermark_sleep=1)
+        pool.start()
+
+        req = zk.NodeRequest()
+        req.state = zk.REQUESTED
+        req.node_types.append('fake-label')
+        self.zk.storeNodeRequest(req)
+
+        req = self.waitForNodeRequest(req)
+        self.assertEqual(req.state, zk.FAILED)