Routing and load balancing in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select the next server using round-robin load balancing.

Microservices

next_server = servers[[1] % len(servers)]

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

Acurrent_index + 1

Blen(servers)

Ccurrent_index

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using len(servers) always picks server 0.

Using current_index repeats the same server.

The current_index variable holds the last used server index. Increment it by 1 and use modulo the number of servers to select the next server in round-robin.

2fill in blank

medium

Complete the code to route requests based on URL path prefix.

Microservices

if request.path.startswith([1]):
    route_to = 'serviceA'
else:
    route_to = 'serviceB'

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

A'/login/'

B'serviceA'

C'/api/v1/'

D'/home/'

Attempts:

3 left

💡 Hint

Common Mistakes

Using service names instead of URL prefixes.

Using unrelated paths like '/login/' when routing API calls.

The routing decision is based on the URL path prefix. '/api/v1/' is a common API prefix to route to serviceA.

3fill in blank

hard

Fix the error in the load balancer health check function.

Microservices

def is_healthy(server):
    response = ping(server)
    return response.status_code == [1]

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

A500

B404

C302

D200

Attempts:

3 left

💡 Hint

Common Mistakes

Using 404 which means not found.

Using 500 which means server error.

A healthy server responds with status code 200 (OK). Other codes indicate errors or redirects.

4fill in blank

hard

Fill both blanks to implement weighted load balancing selection.

Microservices

total_weight = sum(server['weight'] for server in servers)
random_pick = random.uniform(0, [1])
current = 0
for server in servers:
    current += server['weight']
    if current >= [2]:
        selected = server
        break

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Atotal_weight

Brandom_pick

Clen(servers)

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using len(servers) instead of total weight.

Comparing to zero instead of the random pick.

The random_pick is a random number between 0 and total_weight. The loop selects the server where cumulative weight exceeds random_pick.

5fill in blank

hard

Fill all three blanks to complete the request routing with fallback.

Microservices

try:
    response = [1](request)
except [2]:
    response = [3](request)

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

Aprimary_service.handle

BTimeoutError

Cbackup_service.handle

DValueError

Attempts:

3 left

💡 Hint

Common Mistakes

Catching the wrong exception type.

Using the backup service in the try block instead of except.

The code tries to handle the request with the primary service. If a TimeoutError occurs, it falls back to the backup service.