fix(#1781): Handle promise rejections in CloudSQL samples (#1782)

* update cloud sql postgres and mysql samples to handle rejections and exit on unhandled rejections * handled promise rejection for pool and table creation in mysql sample * Update server.js * Update server.js * refactor pool and schema setup * Update region tag Co-authored-by: F. Hinkelmann <[email protected]>
GoogleCloudPlatform · May 7, 2020 · 479077d · 479077d
1 parent ae28735
commit 479077d
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diff --git a/cloud-sql/mysql/mysql/server.js b/cloud-sql/mysql/mysql/server.js
@@ -42,9 +42,8 @@ const logger = winston.createLogger({
 });
 
 // [START cloud_sql_mysql_mysql_create]
-let pool;
 const createPool = async () => {
-  pool = await mysql.createPool({
+  return await mysql.createPool({
     user: process.env.DB_USER, // e.g. 'my-db-user'
     password: process.env.DB_PASS, // e.g. 'my-db-password'
     database: process.env.DB_NAME, // e.g. 'my-database'
@@ -88,7 +87,7 @@ const createPool = async () => {
 };
 // [END cloud_sql_mysql_mysql_create]
 
-const ensureSchema = async () => {
+const ensureSchema = async (pool) => {
   // Wait for tables to be created (if they don't already exist).
   await pool.query(
     `CREATE TABLE IF NOT EXISTS votes
@@ -98,40 +97,66 @@ const ensureSchema = async () => {
   console.log(`Ensured that table 'votes' exists`);
 };
 
-let schemaReady;
-
-createPool().then(() => (schemaReady = ensureSchema()));
-
-const awaitSchema = async (req, res, next) => {
-  await schemaReady;
-  next();
-};
+let pool;
+const poolPromise = createPool()
+  .then(async (pool) => {
+    await ensureSchema(pool);
+    return pool;
+  })
+  .catch((err) => {
+    logger.error(err);
+    process.exit(1)
+  });
 
-app.use(awaitSchema);
+app.use(async (req, res, next) => {
+  if (pool) {
+    return next();
+  }
+  try {
+    pool = await poolPromise;
+    next();
+  }
+  catch (err) {
+    logger.error(err);
+    return next(err);
+  }
+});
 
 // Serve the index page, showing vote tallies.
 app.get('/', async (req, res) => {
-  // Get the 5 most recent votes.
-  const recentVotesQuery = pool.query(
-    'SELECT candidate, time_cast FROM votes ORDER BY time_cast DESC LIMIT 5'
-  );
-
-  // Get votes
-  const stmt = 'SELECT COUNT(vote_id) as count FROM votes WHERE candidate=?';
-  const tabsQuery = pool.query(stmt, ['TABS']);
-  const spacesQuery = pool.query(stmt, ['SPACES']);
-
-  // Run queries concurrently, and wait for them to complete
-  // This is faster than await-ing each query object as it is created
-  const recentVotes = await recentVotesQuery;
-  const [tabsVotes] = await tabsQuery;
-  const [spacesVotes] = await spacesQuery;
-
-  res.render('index.pug', {
-    recentVotes,
-    tabCount: tabsVotes.count,
-    spaceCount: spacesVotes.count,
-  });
+  try {
+    // Get the 5 most recent votes.
+    const recentVotesQuery = pool.query(
+      'SELECT candidate, time_cast FROM votes ORDER BY time_cast DESC LIMIT 5'
+    );
+
+    // Get votes
+    const stmt = 'SELECT COUNT(vote_id) as count FROM votes WHERE candidate=?';
+    const tabsQuery = pool.query(stmt, ['TABS']);
+    const spacesQuery = pool.query(stmt, ['SPACES']);
+
+    // Run queries concurrently, and wait for them to complete
+    // This is faster than await-ing each query object as it is created
+    const recentVotes = await recentVotesQuery;
+    const [tabsVotes] = await tabsQuery;
+    const [spacesVotes] = await spacesQuery;
+
+    res.render('index.pug', {
+      recentVotes,
+      tabCount: tabsVotes.count,
+      spaceCount: spacesVotes.count,
+    });
+  } 
+  catch(err) {
+    logger.error(err);
+    res
+      .status(500)
+      .send(
+        'Unable to load page. Please check the application logs for more details.'
+      )
+      .end();
+  }
+
 });
 
 // Handle incoming vote requests and inserting them into the database.
@@ -153,7 +178,7 @@ app.post('/', async (req, res) => {
     // If something goes wrong, handle the error in this section. This might
     // involve retrying or adjusting parameters depending on the situation.
     // [START_EXCLUDE]
-    logger.err(err);
+    logger.error(err);
     res
       .status(500)
       .send(
@@ -173,4 +198,9 @@ const server = app.listen(PORT, () => {
   console.log('Press Ctrl+C to quit.');
 });
 
+process.on('unhandledRejection', err => {
+  console.error(err);
+  process.exit(1);
+});
+
 module.exports = server;
diff --git a/cloud-sql/mysql/mysql/test/server.test.js b/cloud-sql/mysql/mysql/test/server.test.js
@@ -30,7 +30,7 @@ stubMysql.createPool.returns(poolStub);
 const server = require('../server.js');
 
 it('check index page', async () => {
-  const response = await request(server).get('/').timeout(1000);
+  const response = await request(server).get('/').timeout(3000);
 
   assert.strictEqual(response.status, 200);
 });

diff --git a/cloud-sql/postgres/knex/server.js b/cloud-sql/postgres/knex/server.js
@@ -147,8 +147,8 @@ const getVoteCount = async (knex, candidate) => {
   return await knex('votes').count('vote_id').where('candidate', candidate);
 };
 
-app.get('/', (req, res) => {
-  (async function () {
+app.get('/', async (req, res) => {
+  try {
     // Query the total count of "TABS" from the database.
     const tabsResult = await getVoteCount(knex, 'TABS');
     const tabsTotalVotes = parseInt(tabsResult[0].count);
@@ -183,7 +183,14 @@ app.get('/', (req, res) => {
       voteDiff: voteDiff,
       leaderMessage: leaderMessage,
     });
-  })();
+  }
+  catch(err) {
+    res
+      .status(500)
+      .send('Unable to load page; see logs for more details.')
+      .end();
+  }
+
 });
 
 app.post('/', async (req, res) => {

diff --git a/cloud-sql/sqlserver/mssql/server.js b/cloud-sql/sqlserver/mssql/server.js
@@ -42,7 +42,6 @@ const logger = winston.createLogger({
 });
 
 // [START cloud_sql_server_mssql_create]
-let pool;
 const createPool = async () => {
   let config = {pool: {}};
   config.user = process.env.DB_USER; // e.g. 'my-db-user'
@@ -82,11 +81,11 @@ const createPool = async () => {
   // [END cloud_sql_server_mssql_backoff]
 
   // [END_EXCLUDE]
-  pool = await mssql.connect(config);
+  return await mssql.connect(config);
 };
-// [END cloud_sql_mysql_mysql_create]
+// [END cloud_sql_server_mssql_create]
 
-const ensureSchema = async () => {
+const ensureSchema = async (pool) => {
   // Wait for tables to be created (if they don't already exist).
   await pool.request()
     .query(
@@ -101,21 +100,28 @@ const ensureSchema = async () => {
   console.log(`Ensured that table 'votes' exists`);
 };
 
-let schemaReady;
+let pool;
+const poolPromise = createPool()
+  .then(async (pool) => {
+    await ensureSchema(pool);
+    return pool;
+  })
+  .catch((err) => {
+    logger.error(err);
+    process.exit(1);
+  });
+
 app.use(async (req, res, next) => {
-  if (schemaReady) {
+  if (pool) {
+    return next();
+  }
+  try {
+    pool = await poolPromise;
     next();
   }
-  else {
-    try {
-      await createPool();
-      schemaReady = await ensureSchema();
-      next();
-    }
-    catch (err) {
-      logger.error(err);
-      return next(err);
-    }
+  catch (err) {
+    logger.error(err);
+    return next(err);
   }
 });