[Solved] Consider this pseudocode for a circuit breaker: if state == 'OPEN': return 'fail fast' elif state == 'HALF_OPEN': if test_call_successful(): state = 'CLOSED' else: state = 'OPEN' else:... | Microservices

Microservices - Resilience Patterns

Consider this pseudocode for a circuit breaker:

if state == 'OPEN':
  return 'fail fast'
elif state == 'HALF_OPEN':
  if test_call_successful():
    state = 'CLOSED'
  else:
    state = 'OPEN'
else:
  call_service()

What happens when the circuit breaker is in HALF_OPEN state and the test call fails?

AThe state changes to CLOSED and service calls continue

BThe state remains HALF_OPEN and retries immediately

CThe service call is ignored without state change

DThe state changes back to OPEN and calls are blocked

Step-by-Step Solution

Solution:

Step 1: Analyze HALF_OPEN state logic
In HALF_OPEN, a test call checks if the service recovered. If it fails, the state changes to OPEN.
Step 2: Understand consequence of failure
Changing to OPEN blocks further calls to prevent overload.
Final Answer:
The state changes back to OPEN and calls are blocked -> Option D
Quick Check:
HALF_OPEN fail -> OPEN state [OK]

Quick Trick: Failed test call in HALF_OPEN resets to OPEN [OK]

Common Mistakes:

MISTAKES

Assuming state changes to CLOSED on failure
Thinking retries happen immediately in HALF_OPEN
Ignoring state changes on test failure

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More Microservices Quizzes

Consider this pseudocode for a circuit breaker:

Step 1: Analyze HALF_OPEN state logic

Step 2: Understand consequence of failure

Final Answer:

Quick Check:

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