[Backport main] adding BWC for connector config field

common/src/main/java/org/opensearch/ml/common/transport/connector/MLCreateConnectorInput.java

@@ -7,6 +7,7 @@
 
 import lombok.Builder;
 import lombok.Data;
+import org.opensearch.Version;
 import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.core.common.io.stream.Writeable;
@@ -45,7 +46,7 @@ public class MLCreateConnectorInput implements ToXContentObject, Writeable {
     public static final String ACCESS_MODE_FIELD = "access_mode";
     public static final String DRY_RUN_FIELD = "dry_run";
 
-
+    private static final Version MINIMAL_SUPPORTED_VERSION_FOR_CLIENT_CONFIG = Version.V_2_13_0;
 
     public static final String DRY_RUN_CONNECTOR_NAME = "dryRunConnector";
 
@@ -226,6 +227,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public void writeTo(StreamOutput output) throws IOException {
+        Version streamOutputVersion = output.getVersion();
         output.writeOptionalString(name);
         output.writeOptionalString(description);
         output.writeOptionalString(version);
@@ -266,16 +268,18 @@ public void writeTo(StreamOutput output) throws IOException {
         }
         output.writeBoolean(dryRun);
         output.writeBoolean(updateConnector);
-        if (connectorClientConfig != null) {
-            output.writeBoolean(true);
-            connectorClientConfig.writeTo(output);
-        } else {
-            output.writeBoolean(false);
+        if (streamOutputVersion.onOrAfter(MINIMAL_SUPPORTED_VERSION_FOR_CLIENT_CONFIG)) {
+            if (connectorClientConfig != null) {
+                output.writeBoolean(true);
+                connectorClientConfig.writeTo(output);
+            } else {
+                output.writeBoolean(false);
+            }
         }
-
     }
 
     public MLCreateConnectorInput(StreamInput input) throws IOException {
+        Version streamInputVersion = input.getVersion();
         name = input.readOptionalString();
         description = input.readOptionalString();
         version = input.readOptionalString();
@@ -302,8 +306,11 @@ public MLCreateConnectorInput(StreamInput input) throws IOException {
         }
         dryRun = input.readBoolean();
         updateConnector = input.readBoolean();
-        if (input.readBoolean()) {
-            this.connectorClientConfig = new ConnectorClientConfig(input);
+        if (streamInputVersion.onOrAfter(MINIMAL_SUPPORTED_VERSION_FOR_CLIENT_CONFIG)) {
+            if (input.readBoolean()) {
+                this.connectorClientConfig = new ConnectorClientConfig(input);
+            }
         }
+
     }
 }

common/src/test/java/org/opensearch/ml/common/transport/connector/MLCreateConnectorInputTests.java

@@ -9,6 +9,7 @@
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
+import org.opensearch.Version;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
@@ -218,6 +219,77 @@ public void readInputStream_SuccessWithNullFields() throws IOException {
         });
     }
 
+    @Test
+    public void testBuilder_NullActions_ShouldNotThrowException() {
+        // Actions can be null for a connector without any specific actions defined.
+        MLCreateConnectorInput input = MLCreateConnectorInput.builder()
+                .name("test_connector_name")
+                .description("this is a test connector")
+                .version("1")
+                .protocol("http")
+                .parameters(Map.of("input", "test input value"))
+                .credential(Map.of("key", "test_key_value"))
+                .actions(null) // Setting actions to null
+                .access(AccessMode.PUBLIC)
+                .backendRoles(Arrays.asList("role1", "role2"))
+                .addAllBackendRoles(false)
+                .build();
+
+        assertNull(input.getActions());
+    }
+
+    @Test
+    public void testParse_MissingNameField_ShouldThrowException() throws IOException {
+        String jsonMissingName = "{\"description\":\"this is a test connector\",\"version\":\"1\",\"protocol\":\"http\"}";
+        XContentParser parser = createParser(jsonMissingName);
+
+        exceptionRule.expect(IllegalArgumentException.class);
+        exceptionRule.expectMessage("Connector name is null");
+
+        MLCreateConnectorInput.parse(parser);
+    }
+
+    @Test
+    public void testWriteToVersionCompatibility() throws IOException {
+        MLCreateConnectorInput input = mlCreateConnectorInput; // Assuming mlCreateConnectorInput is already initialized
+
+        // Simulate an older version of OpenSearch that does not support connectorClientConfig
+        Version oldVersion = Version.fromString("2.12.0"); // Change this as per your old version
+        BytesStreamOutput output = new BytesStreamOutput();
+        output.setVersion(oldVersion);
+
+        input.writeTo(output);
+
+        StreamInput streamInput = output.bytes().streamInput();
+        streamInput.setVersion(oldVersion);
+
+        MLCreateConnectorInput deserializedInput = new MLCreateConnectorInput(streamInput);
+
+        // The ConnectorClientConfig should be null as it's not supported in the older version
+        assertNull(deserializedInput.getConnectorClientConfig());
+    }
+
+    @Test
+    public void testDryRunConnectorInput_IgnoreValidation() {
+        MLCreateConnectorInput input = MLCreateConnectorInput.builder()
+                .dryRun(true) // Set dryRun to true
+                .build();
+
+        // No exception for missing mandatory fields when dryRun is true
+        assertTrue(input.isDryRun());
+        assertNull(input.getName()); // Name is not set, but no exception due to dryRun
+    }
+
+    // Helper method to create XContentParser from a JSON string
+    private XContentParser createParser(String jsonString) throws IOException {
+        XContentParser parser = XContentType.JSON.xContent().createParser(
+                new NamedXContentRegistry(new SearchModule(Settings.EMPTY, Collections.emptyList()).getNamedXContents()),
+                LoggingDeprecationHandler.INSTANCE,
+                jsonString);
+        parser.nextToken(); // Move to the first token
+        return parser;
+    }
+
     private void testParseFromJsonString(String expectedInputString, Consumer<MLCreateConnectorInput> verify) throws Exception {
         XContentParser parser = XContentType.JSON.xContent().createParser(new NamedXContentRegistry(new SearchModule(Settings.EMPTY,
                 Collections.emptyList()).getNamedXContents()), LoggingDeprecationHandler.INSTANCE, expectedInputString);