UTIL_CircuitBreaker

Class · Group: Resilience

global inherited sharing class UTIL_CircuitBreaker

Factory for creating circuit breaker instances to prevent cascading failures and provide fast failure when external services are unavailable. The circuit breaker has three states: CLOSED (normal operation), OPEN (failing fast), and HALF_OPEN (testing recovery). Features: Three-state circuit breaker pattern (CLOSED, OPEN, HALF_OPEN) Configurable failure threshold and timeout periods Automatic state transitions based on success/failure rates Integration with Platform Cache for distributed state management Per-service circuit breaker instances with shared state across transactions Detailed state tracking and metrics Convenient execute() helpers for protected actions Circuit States: CLOSED: Normal operation, requests pass through OPEN: Circuit is open, requests fail immediately without attempting the call HALF_OPEN: Testing if service has recovered, limited requests allowed through State Transitions: CLOSED → OPEN: When failure count exceeds threshold OPEN → HALF_OPEN: After timeout period expires HALF_OPEN → CLOSED: When success count indicates recovery HALF_OPEN → OPEN: When failures continue

Example

Example 1: Simple usage with execute() helper (RECOMMENDED)

UTIL_CircuitBreaker.Breaker breaker = UTIL_CircuitBreaker.monitor('API_SendGridEmail');
try
{
    breaker.execute(new SendEmailAction(emailData));
}
catch(UTIL_CircuitBreaker.OpenException e)
{
    // Circuit is open - handle gracefully
}

Example 2: Manual control with allowRequest()

UTIL_CircuitBreaker.Breaker breaker = UTIL_CircuitBreaker.monitor('API_SendGridEmail')
    .withFailureThreshold(5)
    .withTimeout(60);
if(breaker.allowRequest())
{
    try
    {
        // Make webservice call
        breaker.recordSuccess();
    }
    catch(Exception e)
    {
        breaker.recordFailure();
    }
}

Example 3: Integration with API_Outbound

UTIL_CircuitBreaker.Breaker breaker = UTIL_CircuitBreaker.monitor(getServiceName());
if(!breaker.allowRequest())
{
    result.errors.add('Circuit breaker is OPEN - service temporarily unavailable');
    result.isAborted = true;
    return;
}

See Also: API_Outbound, UTIL_Cache, UTIL_Retry

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Methods

Method	Description
global static UTIL_CircuitBreaker.Breaker monitor(String circuitId)	Creates a new circuit breaker instance with default configuration Default configuration: Failure threshold: 5 failures Timeout: 60 seconds Success threshold: 2 successes Half-open max attempts: 3

monitor

global static UTIL_CircuitBreaker.Breaker monitor(String circuitId)

Creates a new circuit breaker instance with default configuration

Default configuration:

• Failure threshold: 5 failures

• Timeout: 60 seconds

• Success threshold: 2 successes

• Half-open max attempts: 3

Parameters

Parameter	Type	Description
circuitId	String	Unique identifier for this circuit (typically service class name)

Returns UTIL_CircuitBreaker.Breaker — A new circuit breaker instance with defaults

Example

// Use defaults
UTIL_CircuitBreaker.Breaker breaker = UTIL_CircuitBreaker.monitor('API_SendGridEmail');
// Customize with fluent API
UTIL_CircuitBreaker.Breaker breaker = UTIL_CircuitBreaker.monitor('API_SendGridEmail')
    .withFailureThreshold(10)
    .withTimeout(120);

Inner Classes

Class	Description
Breaker	Interface for circuit breaker operations.
Metrics	Public class containing circuit breaker metrics
OpenException	Exception thrown when circuit breaker is OPEN and blocks a request
ProtectedAction	Interface for code that needs circuit breaker protection (no return value) Implement this interface to use the simplified execute() method which handles allowRequest(), recordSuccess(), and recordFailure() automatically.
Provider	Interface for code that needs circuit breaker protection (with return value) Implement this interface when your action needs to return data.
State	Enum representing the circuit breaker state

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