add this feature for target attribute:

use ${metadataKey} for value from metadata, $[messageKey] for value from the message body

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

@@ -68,8 +68,11 @@ public abstract class TbEntityGetAttrNode<T extends EntityId> implements TbNode
 
         Map<String, String> mappingsMap = new HashMap<>();
         config.getAttrMapping().forEach((key, value) -> {
-            String processPattern = TbNodeUtils.processPattern(key, msg);
-            mappingsMap.put(processPattern, value);
+            log.info("key = {}, value = {}", key, value);
+            log.info(msg.toString());
+            String processPatternKey = TbNodeUtils.processPattern(key, msg);
+            String processPatternValue = TbNodeUtils.processPattern(value, msg);
+            mappingsMap.put(processPatternKey, processPatternValue);
         });
 
         List<String> keys = List.copyOf(mappingsMap.keySet());
@@ -94,6 +97,7 @@ public abstract class TbEntityGetAttrNode<T extends EntityId> implements TbNode
     private void putAttributesAndTell(TbContext ctx, TbMsg msg, List<? extends KvEntry> attributes, Map<String, String> map) {
         attributes.forEach(r -> {
             String attrName = map.get(r.getKey());
+            log.info("attrName = {}, value = {}", attrName, r.getValueAsString());
             msg.getMetaData().putValue(attrName, r.getValueAsString());
         });
         ctx.tellSuccess(msg);

rule-engine/rule-engine-components/src/test/java/org/thingsboard/rule/engine/metadata/AbstractAttributeNodeTest.java

@@ -72,7 +72,7 @@ public abstract class AbstractAttributeNodeTest {
     final RuleChainId ruleChainId = new RuleChainId(Uuids.timeBased());
     final RuleNodeId ruleNodeId = new RuleNodeId(Uuids.timeBased());
     final String keyAttrConf = "${word}";
-    final String valueAttrConf = "result";
+    final String valueAttrConf = "${result}";
     @Mock
     TbContext ctx;
     @Mock
@@ -95,6 +95,7 @@ public abstract class AbstractAttributeNodeTest {
 
         metaData = new HashMap<>();
         metaData.putIfAbsent("word", "temperature");
+        metaData.putIfAbsent("result", "answer");
 
         this.node = node;
         this.node.init(null, nodeConfiguration);
@@ -181,7 +182,7 @@ public abstract class AbstractAttributeNodeTest {
 
         node.onMsg(ctx, msg);
         verify(ctx).tellSuccess(msg);
-        assertEquals(msg.getMetaData().getValue("result"), "highest");
+        assertEquals(msg.getMetaData().getValue("answer"), "highest");
     }
 
     void entityAttributeFetched(EntityId entityId) {
@@ -193,7 +194,7 @@ public abstract class AbstractAttributeNodeTest {
 
         node.onMsg(ctx, msg);
         verify(ctx).tellSuccess(msg);
-        assertEquals(msg.getMetaData().getValue("result"), "high");
+        assertEquals(msg.getMetaData().getValue("answer"), "high");
     }
 
     TbGetEntityAttrNodeConfiguration getTbNodeConfig() {