DevOps: What is circuit breaker?

1import CircuitBreaker from "opossum";
2
3const breaker = new CircuitBreaker(async () => {
4  const response = await fetch("https://api.example.com/data");
5  return response.json();
6}, {
7  timeout: 3000,        // 3 seconds
8  errorThresholdPercentage: 50,
9  resetTimeout: 30000,  // 30 seconds until retry
10});
11
12breaker.on("open", () => console.log("Circuit opened!"));
13breaker.on("halfOpen", () => console.log("Half-open"));
14breaker.on("close", () => console.log("Circuit closed"));
15breaker.on("fallback", () => console.log("Fallback"));
16
17// Usage
18try {
19  const data = await breaker.fire();
20  console.log(data);
21} catch (err) {
22  console.error("Error:", err);
23}