From ee96d2f7a7223d88951488fc6bc94a73e53eedb7 Mon Sep 17 00:00:00 2001
From: Gabe Gorelick <gabe@hightouch.io>
Date: Mon, 28 Oct 2024 11:45:40 -0400
Subject: [PATCH] Add support for `describeOnly`

Fixes #940
---
 index.d.ts                             |  6 ++++++
 lib/connection/statement.js            | 16 ++++++++++++++++
 lib/constants/error_messages.js        |  1 +
 lib/errors.js                          |  1 +
 test/unit/connection/statement_test.js | 12 +++++++++++-
 5 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/index.d.ts b/index.d.ts
index e2c56ecb4..0d4e17bea 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -131,6 +131,7 @@ declare module 'snowflake-sdk' {
         ERR_CONN_EXEC_STMT_INVALID_FETCH_AS_STRING_VALUES = 409012,
         ERR_CONN_EXEC_STMT_INVALID_REQUEST_ID = 409013,
         ERR_CONN_EXEC_STMT_INVALID_ASYNC_EXEC = 409014,
+        ERR_CONN_EXEC_STMT_INVALID_DESCRIBE_ONLY = 409015,
 
         // 410001
         ERR_CONN_FETCH_RESULT_MISSING_OPTIONS = 410001,
@@ -652,6 +653,11 @@ declare module 'snowflake-sdk' {
          * that is different from the connector directory.
          */
         cwd?: string;
+
+        /**
+         * `true` to enable a describe only query.
+         */
+        describeOnly?: boolean;
     }
 
     export interface RowStatement {
diff --git a/lib/connection/statement.js b/lib/connection/statement.js
index fef7b2cbb..b67f81357 100644
--- a/lib/connection/statement.js
+++ b/lib/connection/statement.js
@@ -353,6 +353,12 @@ function createContextPreExec(
       ErrorCodes.ERR_CONN_EXEC_STMT_INVALID_ASYNC_EXEC);
   }
 
+  // if a describeOnly flag is specified, make sure it's boolean
+  if (Util.exists(statementOptions.describeOnly)) {
+    Errors.checkArgumentValid(Util.isBoolean(statementOptions.describeOnly),
+      ErrorCodes.ERR_CONN_EXEC_STMT_INVALID_DESCRIBE_ONLY);
+  }
+
   // create a statement context
   const statementContext = createStatementContext();
 
@@ -384,6 +390,11 @@ function createContextPreExec(
     statementContext.cwd = statementOptions.cwd;
   }
 
+  // if the describeOnly flag is specified, add it to the statement context
+  if (Util.exists(statementOptions.describeOnly)) {
+    statementContext.describeOnly = statementOptions.describeOnly;
+  }
+
   // validate non-user-specified arguments
   Errors.assertInternal(Util.isObject(services));
   Errors.assertInternal(Util.isObject(connectionConfig));
@@ -1244,6 +1255,11 @@ function sendRequestPreExec(statementContext, onResultAvailable) {
     json.asyncExec = statementContext.asyncExec;
   }
 
+  // include describeOnly flag if a value was specified
+  if (Util.exists(statementContext.describeOnly)) {
+    json.describeOnly = statementContext.describeOnly;
+  }
+
   // use the snowflake service to issue the request
   sendSfRequest(statementContext,
     {
diff --git a/lib/constants/error_messages.js b/lib/constants/error_messages.js
index 4a1c34145..2effda456 100644
--- a/lib/constants/error_messages.js
+++ b/lib/constants/error_messages.js
@@ -126,6 +126,7 @@ exports[409011] = 'Invalid fetchAsString value. The specified value must be an A
 exports[409012] = 'Invalid fetchAsString type: %s. The supported types are: String, Boolean, Number, Date, Buffer, and JSON.';
 exports[409013] = 'Invalid requestId. The specified value must be a string.';
 exports[409014] = 'Invalid asyncExec. The specified value must be a boolean.';
+exports[409015] = 'Invalid describeOnly. The specified value must be a boolean.';
 
 // 410001
 exports[410001] = 'Fetch-result options must be specified.';
diff --git a/lib/errors.js b/lib/errors.js
index b57e4dc39..6a00ad982 100644
--- a/lib/errors.js
+++ b/lib/errors.js
@@ -130,6 +130,7 @@ codes.ERR_CONN_EXEC_STMT_INVALID_FETCH_AS_STRING = 409011;
 codes.ERR_CONN_EXEC_STMT_INVALID_FETCH_AS_STRING_VALUES = 409012;
 codes.ERR_CONN_EXEC_STMT_INVALID_REQUEST_ID = 409013;
 codes.ERR_CONN_EXEC_STMT_INVALID_ASYNC_EXEC = 409014;
+codes.ERR_CONN_EXEC_STMT_INVALID_DESCRIBE_ONLY = 409015;
 
 // 410001
 codes.ERR_CONN_FETCH_RESULT_MISSING_OPTIONS = 410001;
diff --git a/test/unit/connection/statement_test.js b/test/unit/connection/statement_test.js
index eaba007bf..7405b64af 100644
--- a/test/unit/connection/statement_test.js
+++ b/test/unit/connection/statement_test.js
@@ -205,6 +205,16 @@ describe('Statement.execute()', function () {
             connectionConfig: null
           },
         errorCode: ErrorCodes.ERR_CONN_EXEC_STMT_MISSING_SQL_TEXT
+      },
+      {
+        name: 'execute() invalid describeOnly',
+        options: {
+          statementOptions: {
+            sqlText: '',
+            describeOnly: 1,
+          },
+        },
+        errorCode: ErrorCodes.ERR_CONN_EXEC_STMT_INVALID_DESCRIBE_ONLY
       }
     ];
 
@@ -404,4 +414,4 @@ describe('Statement.fetchResult()', function () {
     testCase = testCases[index];
     it(testCase.name, createItCallback(testCase));
   }
-});
\ No newline at end of file
+});