add Related GetAttribute node

rule-engine/rule-engine-api/src/main/java/org/thingsboard/rule/engine/api/TbContext.java

@@ -23,6 +23,7 @@ import org.thingsboard.server.dao.attributes.AttributesService;
 import org.thingsboard.server.dao.customer.CustomerService;
 import org.thingsboard.server.dao.device.DeviceService;
 import org.thingsboard.server.dao.plugin.PluginService;
+import org.thingsboard.server.dao.relation.RelationService;
 import org.thingsboard.server.dao.rule.RuleChainService;
 import org.thingsboard.server.dao.rule.RuleService;
 import org.thingsboard.server.dao.timeseries.TimeseriesService;
@@ -71,4 +72,6 @@ public interface TbContext {
 
     TimeseriesService getTimeseriesService();
 
+    RelationService getRelationService();
+
 }

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/metadata/TbGetRelatedAttrNodeConfiguration.java

@@ -0,0 +1,11 @@
+package org.thingsboard.rule.engine.metadata;
+
+import lombok.Data;
+import org.thingsboard.server.common.data.relation.EntitySearchDirection;
+
+@Data
+public class TbGetRelatedAttrNodeConfiguration {
+
+    private String relationType;
+    private EntitySearchDirection direction;
+}

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/metadata/TbGetRelatedAttributeNode.java

@@ -0,0 +1,47 @@
+package org.thingsboard.rule.engine.metadata;
+
+import com.google.common.util.concurrent.AsyncFunction;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import org.apache.commons.collections.CollectionUtils;
+import org.thingsboard.rule.engine.TbNodeUtils;
+import org.thingsboard.rule.engine.api.TbContext;
+import org.thingsboard.rule.engine.api.TbNodeConfiguration;
+import org.thingsboard.rule.engine.api.TbNodeException;
+import org.thingsboard.rule.engine.api.TbNodeState;
+import org.thingsboard.server.common.data.id.EntityId;
+import org.thingsboard.server.common.data.relation.EntityRelation;
+import org.thingsboard.server.common.data.relation.EntitySearchDirection;
+import org.thingsboard.server.dao.relation.RelationService;
+
+import java.util.List;
+
+import static org.thingsboard.server.common.data.relation.RelationTypeGroup.COMMON;
+
+public class TbGetRelatedAttributeNode extends TbEntityGetAttrNode<EntityId> {
+
+    private TbGetRelatedAttrNodeConfiguration config;
+
+    @Override
+    public void init(TbNodeConfiguration configuration, TbNodeState state) throws TbNodeException {
+        this.config = TbNodeUtils.convert(configuration, TbGetRelatedAttrNodeConfiguration.class);
+    }
+
+    @Override
+    protected ListenableFuture<EntityId> findEntityAsync(TbContext ctx, EntityId originator) {
+        RelationService relationService = ctx.getRelationService();
+        if (config.getDirection() == EntitySearchDirection.FROM) {
+            ListenableFuture<List<EntityRelation>> asyncRelation = relationService.findByFromAndTypeAsync(originator, config.getRelationType(), COMMON);
+            return Futures.transform(asyncRelation, (AsyncFunction<? super List<EntityRelation>, EntityId>)
+                    r -> CollectionUtils.isNotEmpty(r) ? Futures.immediateFuture(r.get(0).getTo())
+                            : Futures.immediateFailedFuture(new IllegalStateException("Relation not found")));
+        } else if (config.getDirection() == EntitySearchDirection.TO) {
+            ListenableFuture<List<EntityRelation>> asyncRelation = relationService.findByToAndTypeAsync(originator, config.getRelationType(), COMMON);
+            return Futures.transform(asyncRelation, (AsyncFunction<? super List<EntityRelation>, EntityId>)
+                    r -> CollectionUtils.isNotEmpty(r) ? Futures.immediateFuture(r.get(0).getFrom())
+                            : Futures.immediateFailedFuture(new IllegalStateException("Relation not found")));
+        }
+
+        return Futures.immediateFailedFuture(new IllegalStateException("Unknown direction"));
+    }
+}