Support feature flags in node repository

This implements feature flags for the node repository. A feature flag can be
toggled on/off for the following dimensions:

1) The node repository (entire zone)
2) A specific node
3) A specific application

Flags must be declared in the `FlagId` enum, this is typically done when
implementing the feature that should be guarded by a flag.

Flag status is stored in ZooKeeper. Inspecting and toggling flag status is done
through a REST API, see `RestApiTest#test_flags()`.

5 files changed, 159 insertions, 0 deletions

diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/flag/FlagsTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/flag/FlagsTest.java
new file mode 100644
index 00000000000..5018b18c491
--- /dev/null
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/flag/FlagsTest.java
@@ -0,0 +1,64 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.flag;
+
+import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.HostName;
+import com.yahoo.vespa.curator.mock.MockCurator;
+import com.yahoo.vespa.hosted.provision.NodeRepository;
+import com.yahoo.vespa.hosted.provision.testutils.MockNodeFlavors;
+import com.yahoo.vespa.hosted.provision.testutils.MockNodeRepository;
+import org.junit.Test;
+
+import java.util.function.Supplier;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * @author mpolden
+ */
+public class FlagsTest {
+
+    @Test
+    public void test_flag_toggling() {
+        NodeRepository nodeRepository = new MockNodeRepository(new MockCurator(), new MockNodeFlavors());
+        Flags flags = nodeRepository.flags();
+        Supplier<Flag> flag = () -> flags.get(FlagId.exclusiveLoadBalancer);
+
+        // Flag is disabled by default
+        assertFalse(flag.get().isEnabled());
+
+        // Toggle flag for a node
+        {
+            HostName node1 = HostName.from("host1");
+            flags.setEnabled(FlagId.exclusiveLoadBalancer, node1, true);
+            assertTrue(flag.get().isEnabled(node1));
+            assertFalse(flag.get().isEnabled());
+            flags.setEnabled(FlagId.exclusiveLoadBalancer, node1, false);
+            assertFalse(flag.get().isEnabled(node1));
+        }
+
+        // Toggle flag for an application
+        {
+            ApplicationId app1 = ApplicationId.from("tenant1", "application1", "default");
+            flags.setEnabled(FlagId.exclusiveLoadBalancer, app1, true);
+            assertTrue(flag.get().isEnabled(app1));
+            assertFalse(flag.get().isEnabled());
+            flags.setEnabled(FlagId.exclusiveLoadBalancer, app1, false);
+            assertFalse(flag.get().isEnabled(app1));
+        }
+
+        // Toggle flag globally
+        {
+            flags.setEnabled(FlagId.exclusiveLoadBalancer, true);
+            assertTrue(flag.get().isEnabled());
+            // Flag is implicitly enabled for all dimensions
+            assertTrue(flag.get().isEnabled(HostName.from("host1")));
+            assertTrue(flag.get().isEnabled(ApplicationId.from("tenant1", "application1", "default")));
+            flags.setEnabled(FlagId.exclusiveLoadBalancer, false);
+            assertFalse(flag.get().isEnabled());
+        }
+    }
+
+
+}
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/FlagSerializerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/FlagSerializerTest.java
new file mode 100644
index 00000000000..15f2289d340
--- /dev/null
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/FlagSerializerTest.java
@@ -0,0 +1,33 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.persistence;
+
+import com.google.common.collect.ImmutableSet;
+import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.vespa.hosted.provision.flag.Flag;
+import com.yahoo.vespa.hosted.provision.flag.FlagId;
+import org.junit.Test;
+
+import java.util.Collections;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * @author mpolden
+ */
+public class FlagSerializerTest {
+
+    @Test
+    public void test_serialization() {
+        Flag flag = new Flag(FlagId.exclusiveLoadBalancer, true,
+                             ImmutableSet.of("host1", "host2"),
+                             Collections.singleton(
+                                     ApplicationId.from("tenant1", "application1", "default")
+                             ));
+        Flag serialized = FlagSerializer.fromJson(FlagSerializer.toJson(flag));
+        assertEquals(flag.id(), serialized.id());
+        assertEquals(flag.isEnabled(), serialized.isEnabled());
+        assertEquals(flag.hostnames(), serialized.hostnames());
+        assertEquals(flag.applications(), serialized.applications());
+    }
+
+}
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/RestApiTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/RestApiTest.java
index 2ff1e403e35..ae7f3f14975 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/RestApiTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/RestApiTest.java
@@ -659,6 +659,44 @@ public class RestApiTest {
                        "]}");
     }
 
+    @Test
+    public void test_flags() throws Exception {
+        assertFile(new Request("http://localhost:8080/nodes/v2/flags/"), "flags1.json");
+
+        // Enable flag for application
+        assertResponse(new Request("http://localhost:8080/nodes/v2/flags/exclusive-load-balancer/application/foo:bar:default",
+                                   new byte[0], Request.Method.POST),
+                       "{\"message\":\"Enabled feature exclusiveLoadBalancer for application 'foo:bar:default'\"}");
+
+        // Enable flag for node
+        assertResponse(new Request("http://localhost:8080/nodes/v2/flags/exclusive-load-balancer/node/host1",
+                                   new byte[0], Request.Method.POST),
+                       "{\"message\":\"Enabled feature exclusiveLoadBalancer for node 'host1'\"}");
+
+        assertFile(new Request("http://localhost:8080/nodes/v2/flags/"), "flags2.json");
+
+        // Enable flag for entire repository
+        assertResponse(new Request("http://localhost:8080/nodes/v2/flags/exclusive-load-balancer",
+                                   new byte[0], Request.Method.POST),
+                       "{\"message\":\"Enabled feature exclusiveLoadBalancer\"}");
+
+        // Disable flag for application
+        assertResponse(new Request("http://localhost:8080/nodes/v2/flags/exclusive-load-balancer/application/foo:bar:default",
+                                   new byte[0], Request.Method.DELETE),
+                       "{\"message\":\"Disabled feature exclusiveLoadBalancer for application 'foo:bar:default'\"}");
+
+        // Disable flag for node
+        assertResponse(new Request("http://localhost:8080/nodes/v2/flags/exclusive-load-balancer/node/host1",
+                                   new byte[0], Request.Method.DELETE),
+                       "{\"message\":\"Disabled feature exclusiveLoadBalancer for node 'host1'\"}");
+
+        // Disable flag for entire repository
+        assertResponse(new Request("http://localhost:8080/nodes/v2/flags/exclusive-load-balancer",
+                                   new byte[0], Request.Method.DELETE),
+                       "{\"message\":\"Disabled feature exclusiveLoadBalancer\"}");
+
+    }
+
     /** Tests the rendering of each node separately to make it easier to find errors */
     @Test
     public void test_single_node_rendering() throws Exception {
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/responses/flags1.json b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/responses/flags1.json
new file mode 100644
index 00000000000..8fd09b4a274
--- /dev/null
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/responses/flags1.json
@@ -0,0 +1,10 @@
+{
+  "flags": [
+    {
+      "id": "exclusive-load-balancer",
+      "enabled": false,
+      "enabledHostnames": [],
+      "enabledApplications": []
+    }
+  ]
+}
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/responses/flags2.json b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/responses/flags2.json
new file mode 100644
index 00000000000..78de52e4e85
--- /dev/null
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/v2/responses/flags2.json
@@ -0,0 +1,14 @@
+{
+  "flags": [
+    {
+      "id": "exclusive-load-balancer",
+      "enabled": false,
+      "enabledHostnames": [
+        "host1"
+      ],
+      "enabledApplications": [
+        "foo:bar:default"
+      ]
+    }
+  ]
+}