From 53fef72b76f3a168664b2cca5e8a070ac4e13c21 Mon Sep 17 00:00:00 2001
From: Luis Ibarra <luissebastianibarrav@gmail.com>
Date: Mon, 16 Feb 2026 18:14:30 -0500
Subject: [PATCH] feat: add support for READ_ONLY connection mode in MSSQL
 plugin

- Implemented connection mode configuration for READ_ONLY, appending "ApplicationIntent=ReadOnly" to the JDBC URL and setting the HikariCP configuration to read-only.
- Updated form.json to include a tooltip explaining the implications of using read-only mode.
- Added unit tests to verify the correct behavior of both READ_ONLY and READ_WRITE connection modes, ensuring the JDBC URL is constructed appropriately based on the selected mode.
---
 .../com/external/plugins/MssqlPlugin.java     |  8 ++++
 .../mssqlPlugin/src/main/resources/form.json  |  1 +
 .../com/external/plugins/MssqlPluginTest.java | 48 +++++++++++++++++++
 3 files changed, 57 insertions(+)

diff --git a/app/server/appsmith-plugins/mssqlPlugin/src/main/java/com/external/plugins/MssqlPlugin.java b/app/server/appsmith-plugins/mssqlPlugin/src/main/java/com/external/plugins/MssqlPlugin.java
index c546fa03c856..be1e3d7677b3 100644
--- a/app/server/appsmith-plugins/mssqlPlugin/src/main/java/com/external/plugins/MssqlPlugin.java
+++ b/app/server/appsmith-plugins/mssqlPlugin/src/main/java/com/external/plugins/MssqlPlugin.java
@@ -626,6 +626,14 @@ private static HikariDataSource createConnectionPool(
 
         addSslOptionsToUrlBuilder(datasourceConfiguration, urlBuilder);
 
+        // Add connection mode configuration for READ_ONLY
+        if (datasourceConfiguration.getConnection() != null
+                && datasourceConfiguration.getConnection().getMode()
+                        == com.appsmith.external.models.Connection.Mode.READ_ONLY) {
+            urlBuilder.append("ApplicationIntent=ReadOnly;");
+            hikariConfig.setReadOnly(true);
+        }
+
         hikariConfig.setJdbcUrl(urlBuilder.toString());
 
         try {
diff --git a/app/server/appsmith-plugins/mssqlPlugin/src/main/resources/form.json b/app/server/appsmith-plugins/mssqlPlugin/src/main/resources/form.json
index 7731ac9421aa..9cf247f923d8 100644
--- a/app/server/appsmith-plugins/mssqlPlugin/src/main/resources/form.json
+++ b/app/server/appsmith-plugins/mssqlPlugin/src/main/resources/form.json
@@ -9,6 +9,7 @@
           "configProperty": "datasourceConfiguration.connection.mode",
           "controlType": "SEGMENTED_CONTROL",
           "initialValue": "READ_WRITE",
+          "tooltipText": "Read-only mode uses ApplicationIntent=ReadOnly. Note: This only enforces read-only connections when using Always On Availability Groups.",
           "options": [
             {
               "label": "Read / Write",
diff --git a/app/server/appsmith-plugins/mssqlPlugin/src/test/java/com/external/plugins/MssqlPluginTest.java b/app/server/appsmith-plugins/mssqlPlugin/src/test/java/com/external/plugins/MssqlPluginTest.java
index 7be16681867a..befcc76ff4d0 100755
--- a/app/server/appsmith-plugins/mssqlPlugin/src/test/java/com/external/plugins/MssqlPluginTest.java
+++ b/app/server/appsmith-plugins/mssqlPlugin/src/test/java/com/external/plugins/MssqlPluginTest.java
@@ -773,4 +773,52 @@ public void testGetEndpointIdentifierForRateLimit_HostPresentPortAbsent_ReturnsC
                 })
                 .verifyComplete();
     }
+
+    @Test
+    public void testReadOnlyConnectionMode() {
+        DatasourceConfiguration dsConfig = createDatasourceConfiguration(container);
+
+        // Set connection mode to READ_ONLY
+        com.appsmith.external.models.Connection connection = new com.appsmith.external.models.Connection();
+        connection.setMode(com.appsmith.external.models.Connection.Mode.READ_ONLY);
+        dsConfig.setConnection(connection);
+
+        // Create connection pool
+        HikariDataSource connectionPool =
+                mssqlPluginExecutor.datasourceCreate(dsConfig).block();
+
+        // Verify the JDBC URL contains ApplicationIntent=ReadOnly
+        assertNotNull(connectionPool);
+        String jdbcUrl = connectionPool.getJdbcUrl();
+        assertTrue(
+                jdbcUrl.contains("ApplicationIntent=ReadOnly"),
+                "JDBC URL should contain ApplicationIntent=ReadOnly parameter");
+
+        // Cleanup
+        connectionPool.close();
+    }
+
+    @Test
+    public void testReadWriteConnectionMode() {
+        DatasourceConfiguration dsConfig = createDatasourceConfiguration(container);
+
+        // Set connection mode to READ_WRITE
+        com.appsmith.external.models.Connection connection = new com.appsmith.external.models.Connection();
+        connection.setMode(com.appsmith.external.models.Connection.Mode.READ_WRITE);
+        dsConfig.setConnection(connection);
+
+        // Create connection pool
+        HikariDataSource connectionPool =
+                mssqlPluginExecutor.datasourceCreate(dsConfig).block();
+
+        // Verify the JDBC URL does NOT contain ApplicationIntent parameter
+        assertNotNull(connectionPool);
+        String jdbcUrl = connectionPool.getJdbcUrl();
+        assertTrue(
+                !jdbcUrl.contains("ApplicationIntent"),
+                "JDBC URL should not contain ApplicationIntent parameter for READ_WRITE mode");
+
+        // Cleanup
+        connectionPool.close();
+    }
 }