add logging

Author: natesilva

README.md

@@ -43,3 +43,4 @@ main();
 * [Streaming result rows](https://bitbucket.org/adp-developers/snowflake-promise/src/master/examples/streaming.js)
 * [Using traditional Promise `then` syntax (and older versions of Node.js)](https://bitbucket.org/adp-developers/snowflake-promise/src/master/examples/oldSchool.js)
     * Node 4.0.0 is the oldest supported version
+* [Turn on logging](https://bitbucket.org/adp-developers/snowflake-promise/src/master/examples/logging.js)

examples/logging.js

@@ -0,0 +1,37 @@
+//
+// Two types of logging are available.
+//
+// * SDK logging messages are emitted by the Snowflake SDK. These can be turned on by
+//   setting logLevel to the desired level (such as 'trace').
+//
+// * You can log SQL queries. This is enabled by passing a _function_ that will receive
+//   a string to be logged. The string includes the database and schema name, the sqlText,
+//   and the (local) elapsed time.
+//
+
+const Snowflake = require('snowflake-promise').Snowflake;
+
+async function main() {
+  const snowflake = new Snowflake({
+    account: '<account name>',
+    username: '<username>',
+    password: '<password>',
+    database: 'SNOWFLAKE_SAMPLE_DATA',
+    schema: 'TPCH_SF1',
+    warehouse: 'DEMO_WH'
+  }, {
+    logLevel: 'trace',          // maximum SDK logLevel
+    logSql: console.log         // SQL statements will be logged to the console
+  });
+
+  await snowflake.connect();
+
+  const rows = await snowflake.execute(
+    'SELECT COUNT(*) FROM CUSTOMER WHERE C_MKTSEGMENT=:1',
+    ['AUTOMOBILE']
+  );
+
+  console.log(rows);
+}
+
+main();

src/Snowflake.ts

@@ -2,13 +2,17 @@ import * as SDK from 'snowflake-sdk';
 
 import { ConnectionOptions } from './types/ConnectionOptions';
 import { ExecuteOptions } from './types/ExecuteOptions';
+import { LoggingOptions } from './types/LoggingOptions';
 import { Statement } from './Statement';
 
 export class Snowflake {
   private readonly sdk_connection;
+  private readonly logSql: (sqlText: string) => void;
 
   /* Creates a new Snowflake instance. */
-  constructor(private readonly connectionOptions: ConnectionOptions) {
+  constructor(connectionOptions: ConnectionOptions, loggingOptions: LoggingOptions​​ = {}) {
+    if (loggingOptions.logLevel) { SDK.configure({ logLevel: loggingOptions.logLevel }); }
+    this.logSql = loggingOptions.logSql || null;
     this.sdk_connection = SDK.createConnection(connectionOptions);
   }
 
@@ -40,7 +44,7 @@ export class Snowflake {
 
   /** Create a Statement. */
   createStatement(options: ExecuteOptions) {
-    return new Statement(this.sdk_connection, options);
+    return new Statement(this.sdk_connection, options, this.logSql);
   }
 
   /** A convenience function to execute a SQL statement and return the resulting rows. */

src/Statement.ts

@@ -17,7 +17,8 @@ export class Statement {
    */
   constructor(
     private readonly connection: any,
-    private readonly executeOptions: ExecuteOptions
+    private readonly executeOptions: ExecuteOptions,
+    private readonly logSql: (sqlText: string) => void = null
   ) {}
 
   /**
@@ -29,12 +30,17 @@ export class Statement {
     if (this.executePromise) { throw new StatementAlreadyExecutedError(); }
 
     this.executePromise = new Promise((resolve, reject) => {
+      let startTime: number;
+
       this.executeOptions['complete'] = (err, stmt, rows) => {
+        const elapsed = Date.now() - startTime;
         if (err) { reject(err); }
+        if (this.logSql) { this.log(elapsed); }
         this.rows = rows;
         resolve();
       };
 
+      startTime = Date.now();
       this.stmt = this.connection.execute(this.executeOptions);
     });
 
@@ -135,4 +141,17 @@ export class Statement {
     if (!this.executePromise) { throw new StatementNotExecutedError(); }
     return this.stmt.getStatementtId();
   }
+
+  /** log execution details */
+  private log(elapsedTime: number) {
+    const state = this.getSessionState();
+    const db = state.getCurrentDatabase();
+    const schema = state.getCurrentSchema();
+    const sqlText = this.getSqlText();
+
+    let logMessage = `Executed (${db}.${schema}): ${sqlText}`;
+    if (logMessage[logMessage.length - 1] !== ';') { logMessage += ';'; }
+    logMessage += `  Elapsed time: ${elapsedTime}ms`;
+    this.logSql(logMessage);
+  }
 }

src/types/LoggingOptions.ts

@@ -0,0 +1,6 @@
+export interface LoggingOptions {
+  /** optional function to log SQL statements (e.g. console.log) */
+  logSql?: (sqlText: string) => void;
+  /** turn on SDK-level logging */
+  logLevel?: 'error' | 'warn' | 'debug' | 'info' | 'trace';
+}