[CDAP-21059] Add support to return stageName in stageConfigurer

cdap-app-templates/cdap-etl/cdap-etl-api/src/main/java/io/cdap/cdap/etl/api/StageConfigurer.java

@@ -35,6 +35,13 @@ public interface StageConfigurer {
   @Nullable
   Schema getInputSchema();
 
+  /**
+   * Returns the name of the stage.
+   *
+   * @return the name of the stage
+   */
+  String getStageName();
+
   /**
    * set the output schema for this stage, or null if its unknown
    *

cdap-app-templates/cdap-etl/cdap-etl-core/src/main/java/io/cdap/cdap/etl/common/DefaultStageConfigurer.java

@@ -95,6 +95,11 @@ public void setErrorSchema(@Nullable Schema errorSchema) {
     errorSchemaSet = true;
   }
 
+  @Override
+  public String getStageName() {
+    return stageName;
+  }
+
   @Override
   public FailureCollector getFailureCollector() {
     if (collector == null) {

cdap-app-templates/cdap-etl/hydrator-test/src/main/java/io/cdap/cdap/etl/mock/common/MockPipelineConfigurer.java

@@ -86,6 +86,11 @@ public void setErrorSchema(@Nullable Schema errorSchema) {
         // no-op
       }
 
+      @Override
+      public String getStageName() {
+        return null;
+      }
+
       public FailureCollector getFailureCollector() {
         return collector;
       }