How to Implement Circuit breaker design pattern in .net core

Question

How to Implementation Circuit breaker design pattern in dot net core

Tahir Ansari · Answer

public class UserService { public void CreateUser(string username) { // Simulate external service call to create user throw new Exception("Failed to create user"); } public string GetUser(int userId) { // Simulate external service call to get user throw new Exception("Failed to get user"); } public void UpdateUser(int userId, string newUsername) { // Simulate external service call to update user throw new Exception("Failed to update user"); } public void DeleteUser(int userId) { // Simulate external service call to delete user throw new Exception("Failed to delete user"); } } public class CircuitBreaker { // ... (previous circuit breaker implementation) public T ExecuteFunction (Func function) { if (_currentState == CircuitState.Open) { throw new CircuitOpenException("Circuit is open"); } try { T result = function(); _failureCount = 0; return result; } catch (Exception ex) { _failureCount++; if (_failureCount >= _failureThreshold) { OpenCircuit(); } throw; } } } public class UserServiceWithCircuitBreaker { private UserService _userService; private CircuitBreaker _circuitBreaker; public UserServiceWithCircuitBreaker(UserService userService, CircuitBreaker circuitBreaker) { _userService = userService; _circuitBreaker = circuitBreaker; } public void CreateUser(string username) { _circuitBreaker.ExecuteFunction(() => _userService.CreateUser(username)); } public string GetUser(int userId) { return _circuitBreaker.ExecuteFunction(() => _userService.GetUser(userId)); } public void UpdateUser(int userId, string newUsername) { _circuitBreaker.ExecuteFunction(() => _userService.UpdateUser(userId, newUsername)); } public void DeleteUser(int userId) { _circuitBreaker.ExecuteFunction(() => _userService.DeleteUser(userId)); } } // Startup.cs public void ConfigureServices(IServiceCollection services) { // ... services.AddScoped (); services.AddSingleton (); services.AddScoped (); // ... } using Microsoft.AspNetCore.Mvc; [ApiController] [Route("api/[controller]")] public class UserController : ControllerBase { private readonly UserServiceWithCircuitBreaker _userService; public UserController(UserServiceWithCircuitBreaker userService) { _userService = userService; } [HttpPost] public IActionResult CreateUser([FromBody] CreateUserRequest request) { try { _userService.CreateUser(request.Username); return Ok("User created successfully"); } catch (CircuitOpenException) { return StatusCode(503, "Service unavailable"); } catch (Exception) { return StatusCode(500, "An error occurred"); } } [HttpGet("{userId}")] public IActionResult GetUser(int userId) { try { var user = _userService.GetUser(userId); return Ok(user); } catch (CircuitOpenException) { return StatusCode(503, "Service unavailable"); } catch (Exception) { return StatusCode(500, "An error occurred"); } } // Other CRUD methods similarly }

Cr Bhargavi · Answer

In your application's startup or configuration, set up a Circuit Breaker policy using Polly. You can do this by creating a custom policy with specified failure thresholds and time durations. Example: using Polly; using Polly.CircuitBreaker; // Create a custom Circuit Breaker policy var circuitBreakerPolicy = Policy.Handle () .CircuitBreakerAsync(3, TimeSpan.FromSeconds(30), (ex, duration) => { // Handle the circuit being broken Console.WriteLine("Circuit breaker opened due to too many exceptions."); }, () => { // Handle the circuit being reset Console.WriteLine("Circuit breaker reset."); }); // Register the policy with your dependency injection container services.AddSingleton(circuitBreakerPolicy);

Jaimin Shethiya · Answer

Hello S A, You install the Polly Package and implement the circuit breaker pattern. You can refer to the below links. https://codingcanvas.com/implementing-retry-and-circuit-breaker-pattern-using-polly/ https://www.twilio.com/blog/using-polly-circuit-breakers-resilient-net-web-service-consumers