Lessons from microservices failures - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to identify the common cause of microservices failure related to network issues.

Microservices

if service_response.status_code == [1]:
    retry_request()

Drag options to blanks, or click blank then click option'

A503

B500

C404

D200

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 500 which is a server error but not specifically service unavailable.

503 Service Unavailable indicates the service is temporarily unable to handle the request, often due to network or overload issues.

2fill in blank

medium

Complete the code to implement a retry mechanism with exponential backoff in microservices communication.

Microservices

for attempt in range(max_retries):
    try:
        call_service()
        break
    except NetworkError:
        sleep([1] ** attempt)

Drag options to blanks, or click blank then click option'

A2

B3

Cattempt

Dmax_retries

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'attempt' as base causes linear backoff, not exponential.

Exponential backoff commonly uses base 2 to increase wait time exponentially after each retry.

3fill in blank

hard

Fix the error in the circuit breaker pattern implementation to prevent cascading failures.

Microservices

if failure_count > [1]:
    open_circuit()
else:
    call_service()

Drag options to blanks, or click blank then click option'

A-1

B5

C100

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 or negative values disables circuit breaker logic.

A threshold like 5 failures is typical to open the circuit and stop calls temporarily.

4fill in blank

hard

Fill both blanks to correctly implement a health check for a microservice.

Microservices

def health_check():
    response = requests.get('[1]')
    return response.status_code == [2]

Drag options to blanks, or click blank then click option'

Ahttp://localhost:8080/health

Bhttp://localhost:8080/status

C200

D404

Attempts:

3 left

💡 Hint

Common Mistakes

Using '/status' or expecting 404 as healthy response.

The health endpoint is commonly '/health' and a 200 status code means service is healthy.

5fill in blank

hard

Fill all three blanks to implement a timeout and fallback in a microservice call.

Microservices

try:
    response = call_service(timeout=[1])
except TimeoutError:
    response = [2]()

if response.status_code == [3]:
    process_response(response)

Drag options to blanks, or click blank then click option'

A5

Bfallback_service

C200

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Using too high timeout or wrong status code.

Timeout is set to 5 seconds, fallback_service is called on timeout, and 200 status means success.