Rate limiting in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the maximum number of requests allowed per user.

Microservices

MAX_REQUESTS_PER_MINUTE = [1]

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A1000

B100

C10

D10000

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the limit too high causing server overload.

Setting the limit too low causing poor user experience.

The typical rate limit is set to 100 requests per minute to balance user experience and server load.

2fill in blank

medium

Complete the code to check if the user has exceeded the rate limit.

Microservices

if user_requests > [1]:
    block_request()

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AMAX_REQUESTS_PER_HOUR

BMAX_REQUESTS_PER_SECOND

CMAX_REQUESTS_PER_MINUTE

DMAX_REQUESTS_TOTAL

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong time window limit variable.

Comparing against a total or hourly limit instead of per-minute.

We compare the user's requests against the per-minute limit to decide blocking.

3fill in blank

hard

Fix the error in the code that resets the request count after the time window.

Microservices

if current_time - window_start >= [1]:
    reset_request_count()

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A1

B3600

C600

D60

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3600 seconds which is 1 hour instead of 1 minute.

Using 600 seconds which is 10 minutes.

The time window for rate limiting is 60 seconds (1 minute), so reset after 60 seconds.

4fill in blank

hard

Fill both blanks to implement a sliding window rate limiter using timestamps.

Microservices

request_times = [t for t in request_times if t > current_time - [1]]
if len(request_times) >= [2]:
    block_request()

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

A60

B100

C120

D50

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the time window and max request count values.

Using a time window longer than the defined rate limit period.

The sliding window is 60 seconds and the max allowed requests is 100 in that window.

5fill in blank

hard

Fill all three blanks to implement token bucket rate limiting logic.

Microservices

tokens = min(capacity, tokens + (current_time - last_checked) * [1])
if tokens < [2]:
    block_request()
else:
    tokens -= [3]

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

Arefill_rate

B1

Ctoken_cost

Dcapacity

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing capacity with refill_rate.

Using token_cost incorrectly in comparison or subtraction.

The refill_rate controls token addition, 1 token is needed per request, and token_cost is subtracted when allowing a request.