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Merged
uziins merged 1 commit into from
Sep 8, 2025
Merged

Refactor MySQL connection handling; improve error logging and streaml… #5

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51 changes: 10 additions & 41 deletions lib/mysql.js
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Original file line number Diff line number Diff line change
Expand Up @@ -12,26 +12,17 @@ const pool = mysql.createPool({
queueLimit: 0
});

// Variable to store interval ID
let keepAliveInterval = null;

// Event listener for monitoring pool
pool.on('connection', function (connection) {
console.log('New MySQL connection established as id ' + connection.threadId);

// Set session timeout for this connection
connection.query("SET SESSION wait_timeout = 28800");
connection.query("SET SESSION interactive_timeout = 28800");
});

pool.on('error', function(err) {
console.log('MySQL Pool Error:', err);
if(err.code === 'PROTOCOL_CONNECTION_LOST') {
console.log('Connection lost, pool will handle reconnection automatically');
}
console.error('MySQL Pool Error:', err);
});

// Function to retry query with exponential backoff
const retryQuery = async (queryStr, bindings = [], maxRetries = 3, delay = 1000) => {
for (let attempt = 1; attempt <= maxRetries; attempt++) {
try {
Expand All @@ -44,27 +35,23 @@ const retryQuery = async (queryStr, bindings = [], maxRetries = 3, delay = 1000)
});
});
} catch (err) {
// Only retry for connection-related errors
const isConnectionError = (
err.code === 'PROTOCOL_CONNECTION_LOST' ||
err.code === 'ECONNRESET' ||
err.code === 'ETIMEDOUT' ||
err.code === 'ENOTFOUND' ||
err.code === 'ECONNREFUSED' ||
err.code === 4031 ||
err.errno === 2013 || // Lost connection to MySQL server during query
err.errno === 2006 // MySQL server has gone away
err.errno === 2013 ||
err.errno === 2006
Comment on lines +45 to +46
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Copilot AI Sep 8, 2025

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The error code duplication between retryQuery and query functions creates maintenance burden. Consider extracting this logic into a shared helper function like isConnectionError(err) to avoid code duplication and ensure consistency.

Copilot uses AI. Check for mistakes.
);

// If not a connection error or already reached max retry, throw immediately
if (!isConnectionError || attempt >= maxRetries) {
throw err;
}

console.log(`Query attempt ${attempt} failed (connection error):`, err.message);
console.log(`Retrying in ${delay}ms... (attempt ${attempt + 1}/${maxRetries})`);
await new Promise(resolve => setTimeout(resolve, delay));
delay *= 2; // Exponential backoff
delay *= 2;
}
}
};
Expand All @@ -73,7 +60,6 @@ const query = async (queryStr, bindings = []) => {
try {
return await retryQuery(queryStr, bindings);
} catch (err) {
// Only log error if this is a connection error that has been retried
const isConnectionError = (
err.code === 'PROTOCOL_CONNECTION_LOST' ||
err.code === 'ECONNRESET' ||
Expand All @@ -85,71 +71,56 @@ const query = async (queryStr, bindings = []) => {
err.errno === 2006
);

// Only log if connection error (since it has been retried)
if (isConnectionError) {
console.log('Final query error after retries:', err);
console.error('Final query error after retries:', err);
}

throw err;
}
};

// Function to test connection
const testConnection = async () => {
try {
await query('SELECT 1');
console.log('Database connection test successful');
return true;
} catch (err) {
console.log('Database connection test failed:', err.message);
console.error('Database connection test failed:', err.message);
return false;
}
};

// Function to start keep-alive
const startKeepAlive = () => {
if (keepAliveInterval) {
console.log('Keep-alive already running');
return;
}

keepAliveInterval = setInterval(async () => {
try {
await query('SELECT 1');
console.log('Keep-alive query successful');
} catch (err) {
console.log('Keep-alive query failed:', err.message);
console.error('Keep-alive query failed:', err.message);
}
}, 300000); // Every 5 minutes

console.log('Keep-alive started (every 5 minutes)');
}, 300000);
};

// Function to stop keep-alive
const stopKeepAlive = () => {
if (keepAliveInterval) {
clearInterval(keepAliveInterval);
keepAliveInterval = null;
console.log('Keep-alive stopped');
} else {
console.log('Keep-alive is not running');
}
};

// Function to close pool with graceful shutdown
const closePool = () => {
return new Promise((resolve) => {
// Stop keep-alive first
stopKeepAlive();

pool.end(() => {
console.log('MySQL pool closed');
resolve();
});
});
};

// Function for comprehensive health check
const healthCheck = async () => {
const health = {
status: 'unknown',
Expand Down Expand Up @@ -180,7 +151,6 @@ const healthCheck = async () => {
health.database.responseTime = responseTime;
health.status = 'healthy';

// Additional check for response time
if (responseTime > 5000) {
health.status = 'slow';
} else if (responseTime > 1000) {
Expand All @@ -191,8 +161,7 @@ const healthCheck = async () => {
health.database.connected = false;
health.database.error = err.message;
health.status = 'unhealthy';

console.log('Health check failed:', err.message);
console.error('Health check failed:', err.message);
}

return health;
Expand All @@ -204,7 +173,7 @@ const isHealthy = async () => {
await query('SELECT 1');
return true;
} catch (err) {
console.log('Health check failed:', err.message);
console.error('Health check failed:', err.message);
return false;
}
};
Expand Down
10 changes: 5 additions & 5 deletions package-lock.json
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2 changes: 1 addition & 1 deletion package.json
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
{
"name": "letsql",
"version": "1.2.1",
"version": "1.2.2",
"description": "A lightweight and user-friendly Node.js ORM module for MySQL databases. Inspired by Eloquent in Laravel.",
"main": "index.js",
"scripts": {
Expand Down