[Transform] implement node.transform to control where to run a transf…

…orm (#52712)

implement transform node attributes to disable transform on certain nodes and test which nodes are allowed to do remote connections

closes #52200
closes #50033
closes #48734

docs/reference/settings/data-frames-settings.asciidoc → docs/reference/settings/transform-settings.asciidoc

@@ -1,6 +1,6 @@
 
 [role="xpack"]
-[[data-frames-settings]]
+[[transform-settings]]
 === {transforms-cap}  settings in Elasticsearch
 [subs="attributes"]
 ++++
@@ -9,17 +9,30 @@
 
 You do not need to configure any settings to use {transforms}. It is enabled by default.
 
-All of these settings can be added to the `elasticsearch.yml` configuration file. 
-The dynamic settings can also be updated across a cluster with the 
+All of these settings can be added to the `elasticsearch.yml` configuration file.
+The dynamic settings can also be updated across a cluster with the
 <<cluster-update-settings,cluster update settings API>>.
 
-TIP: Dynamic settings take precedence over settings in the `elasticsearch.yml` 
+TIP: Dynamic settings take precedence over settings in the `elasticsearch.yml`
 file.
 
 [float]
-[[general-data-frames-settings]]
+[[general-transform-settings]]
 ==== General {transforms} settings
 
+`node.transform`::
+Set to `true` to identify the node as a _transform node_. The default is `false` if
+either `node.data` or `xpack.transform.enabled` is `false` for the node, and `true` otherwise. +
++
+If set to `false` in `elasticsearch.yml`, the node cannot run transforms. If set to
+`true` but `xpack.transform.enabled` is set to `false`, the `node.transform` setting is
+ignored and the node cannot run transforms. If you want to run transforms, there must be at
+least one transform node in your cluster. +
++
+IMPORTANT: It is advised to use the `node.transform` setting to constrain the execution
+of transforms to certain nodes instead of using `xpack.transform.enabled`. On dedicated
+coordinating nodes or dedicated master nodes, disable the node.transform role.
+
 `xpack.transform.enabled`::
 Set to `true` (default) to enable {transforms} on the node. +
 +

docs/reference/setup.asciidoc

@@ -51,7 +51,7 @@ include::settings/audit-settings.asciidoc[]
 
 include::settings/ccr-settings.asciidoc[]
 
-include::settings/data-frames-settings.asciidoc[]
+include::settings/transform-settings.asciidoc[]
 
 include::settings/ilm-settings.asciidoc[]
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/SourceConfig.java

@@ -15,6 +15,7 @@
 import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.license.RemoteClusterLicenseChecker;
 import org.elasticsearch.xpack.core.transform.utils.ExceptionsHelper;
 
 import java.io.IOException;
@@ -98,6 +99,10 @@ public boolean isValid() {
         return queryConfig.isValid();
     }
 
+    public boolean requiresRemoteCluster() {
+        return Arrays.stream(index).anyMatch(RemoteClusterLicenseChecker::isRemoteIndex);
+    }
+
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeStringArray(index);

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/TransformTaskParams.java

@@ -25,29 +25,35 @@ public class TransformTaskParams extends AbstractDiffable<TransformTaskParams> i
 
     public static final String NAME = TransformField.TASK_NAME;
     public static final ParseField FREQUENCY = TransformField.FREQUENCY;
+    public static final ParseField REQUIRES_REMOTE = new ParseField("requires_remote");
 
     private final String transformId;
     private final Version version;
     private final TimeValue frequency;
+    private final Boolean requiresRemote;
 
     public static final ConstructingObjectParser<TransformTaskParams, Void> PARSER = new ConstructingObjectParser<>(NAME, true,
-            a -> new TransformTaskParams((String) a[0], (String) a[1], (String) a[2]));
+            a -> new TransformTaskParams((String) a[0], (String) a[1], (String) a[2], (Boolean) a[3]));
 
     static {
         PARSER.declareString(ConstructingObjectParser.constructorArg(), TransformField.ID);
         PARSER.declareString(ConstructingObjectParser.optionalConstructorArg(), TransformField.VERSION);
         PARSER.declareString(ConstructingObjectParser.optionalConstructorArg(), FREQUENCY);
+        PARSER.declareBoolean(ConstructingObjectParser.optionalConstructorArg(), REQUIRES_REMOTE);
     }
 
-    private TransformTaskParams(String transformId, String version, String frequency) {
+    private TransformTaskParams(String transformId, String version, String frequency, Boolean remote) {
         this(transformId, version == null ? null : Version.fromString(version),
-            frequency == null ? null : TimeValue.parseTimeValue(frequency, FREQUENCY.getPreferredName()));
+            frequency == null ? null : TimeValue.parseTimeValue(frequency, FREQUENCY.getPreferredName()),
+                    remote == null ? false : remote.booleanValue()
+                    );
     }
 
-    public TransformTaskParams(String transformId, Version version, TimeValue frequency) {
+    public TransformTaskParams(String transformId, Version version, TimeValue frequency, boolean remote) {
         this.transformId = transformId;
         this.version = version == null ? Version.V_7_2_0 : version;
         this.frequency = frequency;
+        this.requiresRemote = remote;
     }
 
     public TransformTaskParams(StreamInput in) throws IOException {
@@ -62,6 +68,11 @@ public TransformTaskParams(StreamInput in) throws IOException {
         } else {
             this.frequency = null;
         }
+        if (in.getVersion().onOrAfter(Version.V_8_0_0)) { // todo: V_7_7_0
+            this.requiresRemote = in.readBoolean();
+        } else {
+            this.requiresRemote = false;
+        }
     }
 
     @Override
@@ -83,6 +94,9 @@ public void writeTo(StreamOutput out) throws IOException {
         if (out.getVersion().onOrAfter(Version.V_7_3_0)) {
             out.writeOptionalTimeValue(frequency);
         }
+        if (out.getVersion().onOrAfter(Version.V_8_0_0)) { // todo: V_7_7_0
+            out.writeBoolean(requiresRemote);
+        }
     }
 
     @Override
@@ -93,6 +107,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         if (frequency != null) {
             builder.field(FREQUENCY.getPreferredName(), frequency.getStringRep());
         }
+        builder.field(REQUIRES_REMOTE.getPreferredName(), requiresRemote);
         builder.endObject();
         return builder;
     }
@@ -109,6 +124,10 @@ public TimeValue getFrequency() {
         return frequency;
     }
 
+    public boolean requiresRemote() {
+        return requiresRemote;
+    }
+
     public static TransformTaskParams fromXContent(XContentParser parser) throws IOException {
         return PARSER.parse(parser, null);
     }
@@ -127,11 +146,12 @@ public boolean equals(Object other) {
 
         return Objects.equals(this.transformId, that.transformId)
             && Objects.equals(this.version, that.version)
-            && Objects.equals(this.frequency, that.frequency);
+            && Objects.equals(this.frequency, that.frequency)
+            && this.requiresRemote == that.requiresRemote;
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(transformId, version, frequency);
+        return Objects.hash(transformId, version, frequency, requiresRemote);
     }
 }

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/transform/transforms/SourceConfigTests.java

@@ -59,4 +59,21 @@ protected Reader<SourceConfig> instanceReader() {
         return SourceConfig::new;
     }
 
+    public void testRequiresRemoteCluster() {
+        assertFalse(new SourceConfig(new String [] {"index1", "index2", "index3"},
+                QueryConfigTests.randomQueryConfig()).requiresRemoteCluster());
+
+        assertTrue(new SourceConfig(new String [] {"index1", "remote2:index2", "index3"},
+                QueryConfigTests.randomQueryConfig()).requiresRemoteCluster());
+
+        assertTrue(new SourceConfig(new String [] {"index1", "index2", "remote3:index3"},
+                QueryConfigTests.randomQueryConfig()).requiresRemoteCluster());
+
+        assertTrue(new SourceConfig(new String [] {"index1", "remote2:index2", "remote3:index3"},
+                QueryConfigTests.randomQueryConfig()).requiresRemoteCluster());
+
+        assertTrue(new SourceConfig(new String [] {"remote1:index1"},
+                QueryConfigTests.randomQueryConfig()).requiresRemoteCluster());
+    }
+
 }

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/transform/transforms/TransformTests.java

@@ -27,7 +27,7 @@ protected TransformTaskParams doParseInstance(XContentParser parser) throws IOEx
     @Override
     protected TransformTaskParams createTestInstance() {
         return new TransformTaskParams(randomAlphaOfLength(10), randomBoolean() ? null : Version.CURRENT,
-            randomBoolean() ? null : TimeValue.timeValueMillis(randomIntBetween(1_000, 3_600_000)));
+            randomBoolean() ? null : TimeValue.timeValueMillis(randomIntBetween(1_000, 3_600_000)), randomBoolean());
     }
 
     @Override

x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/Transform.java

@@ -14,12 +14,14 @@
 import org.elasticsearch.client.Client;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.metadata.IndexTemplateMetaData;
+import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.settings.ClusterSettings;
 import org.elasticsearch.common.settings.IndexScopedSettings;
 import org.elasticsearch.common.settings.Setting;
+import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.SettingsFilter;
 import org.elasticsearch.common.settings.SettingsModule;
@@ -39,6 +41,7 @@
 import org.elasticsearch.threadpool.ExecutorBuilder;
 import org.elasticsearch.threadpool.FixedExecutorBuilder;
 import org.elasticsearch.threadpool.ThreadPool;
+import org.elasticsearch.transport.RemoteClusterService;
 import org.elasticsearch.watcher.ResourceWatcherService;
 import org.elasticsearch.xpack.core.XPackPlugin;
 import org.elasticsearch.xpack.core.XPackSettings;
@@ -137,6 +140,23 @@ public class Transform extends Plugin implements SystemIndexPlugin, PersistentTa
         Setting.Property.Dynamic
     );
 
+    /**
+     * Node attributes for transform, automatically created and retrievable via cluster state.
+     * These attributes should never be set directly, use the node setting counter parts instead.
+     */
+    public static final String TRANSFORM_ENABLED_NODE_ATTR = "transform.node";
+    public static final String TRANSFORM_REMOTE_ENABLED_NODE_ATTR = "transform.remote_connect";
+
+    /**
+     * Setting whether transform (the coordinator task) can run on this node and REST API's are available,
+     * respects xpack.transform.enabled (for the whole plugin) as fallback
+     */
+    public static final Setting<Boolean> TRANSFORM_ENABLED_NODE = Setting.boolSetting(
+        "node.transform",
+        settings -> Boolean.toString(XPackSettings.TRANSFORM_ENABLED.get(settings) && DiscoveryNode.isDataNode(settings)),
+        Property.NodeScope
+    );
+
     public Transform(Settings settings) {
         this.settings = settings;
         this.enabled = XPackSettings.TRANSFORM_ENABLED.get(settings);
@@ -222,8 +242,14 @@ public List<ExecutorBuilder<?>> getExecutorBuilders(Settings settings) {
             return emptyList();
         }
 
-        FixedExecutorBuilder indexing = new FixedExecutorBuilder(settings, TASK_THREAD_POOL_NAME, 4, 4, "transform.task_thread_pool",
-            false);
+        FixedExecutorBuilder indexing = new FixedExecutorBuilder(
+            settings,
+            TASK_THREAD_POOL_NAME,
+            4,
+            4,
+            "transform.task_thread_pool",
+            false
+        );
 
         return Collections.singletonList(indexing);
     }
@@ -296,13 +322,44 @@ public List<PersistentTasksExecutor<?>> getPersistentTasksExecutor(
         // the transform services should have been created
         assert transformServices.get() != null;
 
-        return Collections.singletonList(new TransformPersistentTasksExecutor(client, transformServices.get(), threadPool, clusterService,
-            settingsModule.getSettings(), expressionResolver));
+        return Collections.singletonList(
+            new TransformPersistentTasksExecutor(
+                client,
+                transformServices.get(),
+                threadPool,
+                clusterService,
+                settingsModule.getSettings(),
+                expressionResolver
+            )
+        );
     }
 
     @Override
     public List<Setting<?>> getSettings() {
-        return Collections.singletonList(NUM_FAILURE_RETRIES_SETTING);
+        return Collections.unmodifiableList(Arrays.asList(TRANSFORM_ENABLED_NODE, NUM_FAILURE_RETRIES_SETTING));
+    }
+
+    @Override
+    public Settings additionalSettings() {
+        String transformEnabledNodeAttribute = "node.attr." + TRANSFORM_ENABLED_NODE_ATTR;
+        String transformRemoteEnabledNodeAttribute = "node.attr." + TRANSFORM_REMOTE_ENABLED_NODE_ATTR;
+
+        if (settings.get(transformEnabledNodeAttribute) != null || settings.get(transformRemoteEnabledNodeAttribute) != null) {
+            throw new IllegalArgumentException(
+                "Directly setting transform node attributes is not permitted, please use the documented node settings instead"
+            );
+        }
+
+        if (enabled == false) {
+            return Settings.EMPTY;
+        }
+
+        Settings.Builder additionalSettings = Settings.builder();
+
+        additionalSettings.put(transformEnabledNodeAttribute, TRANSFORM_ENABLED_NODE.get(settings));
+        additionalSettings.put(transformRemoteEnabledNodeAttribute, RemoteClusterService.ENABLE_REMOTE_CLUSTERS.get(settings));
+
+        return additionalSettings.build();
     }
 
     @Override