/**
* Load test for MCP Observability Sidecar
* Sends standard MCP JSON-RPC requests
*/
const url = process.env.URL || 'http://localhost:4000';
const concurrent = Number(process.env.CONCURRENCY || 20);
const total = Number(process.env.TOTAL || 200);
// MCP method mix for realistic load
const methods = [
{ method: 'initialize', weight: 0.05 },
{ method: 'tools/list', weight: 0.30 },
{ method: 'tools/call', weight: 0.40 },
{ method: 'resources/list', weight: 0.15 },
{ method: 'resources/read', weight: 0.10 },
];
function randomMethod(): string {
const rand = Math.random();
let cumulative = 0;
for (const { method, weight } of methods) {
cumulative += weight;
if (rand < cumulative) return method;
}
return 'tools/list';
}
function createRequest(i: number) {
const method = randomMethod();
const request: any = {
jsonrpc: '2.0',
id: i,
method,
};
// Add params based on method
if (method === 'initialize') {
request.params = {
protocolVersion: '2024-11-05',
capabilities: {},
clientInfo: { name: 'loadtest', version: '1.0.0' },
};
} else if (method === 'tools/call') {
request.params = {
name: 'get-weather',
arguments: { location: 'San Francisco, CA' },
};
} else if (method === 'resources/read') {
request.params = {
uri: 'weather://current',
};
}
return request;
}
async function sendRequest(i: number): Promise<void> {
const body = createRequest(i);
const res = await fetch(url, {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify(body),
});
if (!res.ok) {
throw new Error(`HTTP ${res.status}`);
}
await res.json();
}
(async () => {
console.log(`
🔥 MCP Load Test
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
URL: ${url}
Total: ${total} requests
Concurrency: ${concurrent}
Methods: ${methods.map(m => m.method).join(', ')}
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
`);
const startTime = Date.now();
let inFlight = 0;
let done = 0;
let i = 0;
let err = 0;
const next = async () => {
if (i >= total) return;
const idx = i++;
inFlight++;
try {
await sendRequest(idx);
} catch (e) {
err++;
} finally {
inFlight--;
done++;
if (done % 20 === 0 || done === total) {
const elapsed = ((Date.now() - startTime) / 1000).toFixed(1);
const rps = (done / (Date.now() - startTime) * 1000).toFixed(1);
console.log(` ${done}/${total} requests (${err} errors) | ${rps} req/s | ${elapsed}s elapsed`);
}
next();
}
};
// Start concurrent requests
for (let k = 0; k < concurrent; k++) {
next();
}
})();
