Support avro arrays for postgres insertion.

v2/datastream-to-sql/src/main/java/com/google/cloud/teleport/v2/utils/DatastreamToDML.java

@@ -295,7 +295,6 @@ public String getValueSql(JsonNode rowObj, String columnName, Map<String, String
     } else {
       columnValue = columnObj.toString();
     }
-
     return cleanDataTypeValueSql(columnValue, columnName, tableSchema);
   }
 

v2/datastream-to-sql/src/main/java/com/google/cloud/teleport/v2/utils/DatastreamToPostgresDML.java

@@ -15,8 +15,13 @@
  */
 package com.google.cloud.teleport.v2.utils;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.cloud.teleport.v2.datastream.io.CdcJdbcIO.DataSourceConfiguration;
 import com.google.cloud.teleport.v2.datastream.values.DatastreamRow;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -102,6 +107,56 @@
         }
         break;
     }
+    // Arrays in Postgres are prefixed with underscore e.g. _INT4 for integer array.
+    if (dataType.startsWith("_")) {
+      return convertJsonToPostgresArray(columnValue);
+    }
     return columnValue;
   }
+
+  private String convertJsonToPostgresArray(String jsonValue) {
+    if (jsonValue == null || jsonValue.equals("''") || jsonValue.equals("")) {
+      return getNullValueSql();
+    }
+
+    try {
+      ObjectMapper mapper = new ObjectMapper();
+      JsonNode rootNode = mapper.readTree(jsonValue);
+
+      if (!(rootNode.isObject() && rootNode.has("nestedArray"))) {
+        LOG.warn("Empty array: {}", jsonValue);
+        return getNullValueSql();
+      }
+
+      JsonNode arrayNode = rootNode.get("nestedArray");
+
+      // Handle nested structure with elementValue
+      List<String> elements = new ArrayList<>();
+      if (arrayNode.isArray()) {
+        for (JsonNode element : arrayNode) {
+          if (element.has("elementValue")) {
+            JsonNode elementValue = element.get("elementValue");
+            if (!elementValue.isNull()) {
+              elements.add(formatArrayElement(elementValue));
+            } else {
+              elements.add(getNullValueSql());
+            }
+          } else if (!element.isNull()) {
+            elements.add(formatArrayElement(element));
+          }
+        }
+      }
+      return "ARRAY[" + String.join(",", elements) + "]";
+    } catch (JsonProcessingException e) {
+      LOG.error("Error parsing JSON array: {}", jsonValue);
+      return getNullValueSql();
+    }
+  }
+
+  private String formatArrayElement(JsonNode element) {
+    if (element.isTextual()) {
+      return "\'" + cleanSql(element.textValue()) + "\'";
+    }
+    return element.toString();
+  }
 }

v2/datastream-to-sql/src/test/java/com/google/cloud/teleport/v2/utils/DatastreamToDMLTest.java

@@ -33,7 +33,7 @@
 public class DatastreamToDMLTest {
 
   private static final Logger LOG = LoggerFactory.getLogger(DatastreamToDMLTest.class);
-  private String jsonString =
+  private static final String JSON_STRING =
       "{"
           + "\"text_column\":\"value\","
           + "\"quoted_text_column\":\"Test Values: '!@#$%^\","
@@ -42,7 +42,7 @@ public class DatastreamToDMLTest {
           + "\"_metadata_table\":\"MY_TABLE$NAME\""
           + "}";
 
-  private JsonNode getRowObj() {
+  private JsonNode getRowObj(String jsonString) {
     ObjectMapper mapper = new ObjectMapper();
     JsonNode rowObj;
     try {
@@ -59,7 +59,7 @@ private JsonNode getRowObj() {
    */
   @Test
   public void testGetValueSql() {
-    JsonNode rowObj = this.getRowObj();
+    JsonNode rowObj = this.getRowObj(JSON_STRING);
 
     String expectedTextContent = "'value'";
     String testSqlContent =
@@ -82,14 +82,86 @@ public void testGetValueSql() {
     assertEquals(expectedNullByteTextContent, testNullByteSqlContent);
   }
 
+  /**
+   * Test whether {@link DatastreamToPostgresDML#getValueSql(JsonNode, String, Map)} converts array
+   * data into correct integer array syntax.
+   */
+  @Test
+  public void testIntArrayWithNullTypeCoercion() {
+    String arrayJson =
+        "{\"number_array\": {"
+            + "\"nestedArray\": ["
+            + "  {\"nestedArray\": null, \"elementValue\": null},"
+            + "  {\"nestedArray\": null, \"elementValue\": 456}"
+            + "], \"elementValue\": null}}";
+    JsonNode rowObj = this.getRowObj(arrayJson);
+    Map<String, String> tableSchema = new HashMap<>();
+    tableSchema.put("number_array", "_int4");
+    DatastreamToPostgresDML dml = DatastreamToPostgresDML.of(null);
+    String expectedInt = "ARRAY[NULL,456]";
+
+    String actualInt =
+        DatastreamToPostgresDML.of(null).getValueSql(rowObj, "number_array", tableSchema);
+
+    assertEquals(expectedInt, actualInt);
+  }
+
+  /**
+   * Test whether {@link DatastreamToPostgresDML#getValueSql(JsonNode, String, Map)} converts array
+   * data into correct integer array syntax.
+   */
+  @Test
+  public void testIntArrayTypeCoercion() {
+    String arrayJson =
+        "{\"number_array\": {"
+            + "\"nestedArray\": ["
+            + "  {\"nestedArray\": null, \"elementValue\": 123},"
+            + "  {\"nestedArray\": null, \"elementValue\": 456}"
+            + "], \"elementValue\": null}}";
+    JsonNode rowObj = this.getRowObj(arrayJson);
+    Map<String, String> tableSchema = new HashMap<>();
+    tableSchema.put("number_array", "_int4");
+    DatastreamToPostgresDML dml = DatastreamToPostgresDML.of(null);
+    String expectedInt = "ARRAY[123,456]";
+
+    String actualInt =
+        DatastreamToPostgresDML.of(null).getValueSql(rowObj, "number_array", tableSchema);
+
+    assertEquals(expectedInt, actualInt);
+  }
+
+  /**
+   * Test whether {@link DatastreamToPostgresDML#getValueSql(JsonNode, String, Map)} converts array
+   * data into correct text array syntax.
+   */
+  @Test
+  public void testTextArrayTypeCoercion() {
+    String arrayJson =
+        "{\"text_array\": {"
+            + "\"nestedArray\": ["
+            + "  {\"nestedArray\": null, \"elementValue\": \"apple\"},"
+            + "  {\"nestedArray\": null, \"elementValue\": \"cherry\"}"
+            + "], \"elementValue\": null}}";
+    JsonNode rowObj = this.getRowObj(arrayJson);
+    Map<String, String> tableSchema = new HashMap<>();
+    tableSchema.put("text_array", "_text");
+    DatastreamToPostgresDML dml = DatastreamToPostgresDML.of(null);
+    String expectedInt = "ARRAY['apple','cherry']";
+
+    String actualInt =
+        DatastreamToPostgresDML.of(null).getValueSql(rowObj, "text_array", tableSchema);
+
+    assertEquals(expectedInt, actualInt);
+  }
+
   /**
    * Test whether {@link DatastreamToDML#getTargetSchemaName} converts the Oracle schema into the
    * correct Postgres schema.
    */
   @Test
   public void testGetPostgresSchemaName() {
     DatastreamToDML datastreamToDML = DatastreamToPostgresDML.of(null);
-    JsonNode rowObj = this.getRowObj();
+    JsonNode rowObj = this.getRowObj(JSON_STRING);
     DatastreamRow row = DatastreamRow.of(rowObj);
 
     String expectedSchemaName = "my_schema";
@@ -104,7 +176,7 @@ public void testGetPostgresSchemaName() {
   @Test
   public void testGetPostgresTableName() {
     DatastreamToDML datastreamToDML = DatastreamToPostgresDML.of(null);
-    JsonNode rowObj = this.getRowObj();
+    JsonNode rowObj = this.getRowObj(JSON_STRING);
     DatastreamRow row = DatastreamRow.of(rowObj);
 
     String expectedTableName = "my_table$name";