Timetables for complex schedules in Apache Airflow - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a daily timetable starting at midnight.

Apache Airflow

from airflow.timetables.base import Timetable
class DailyMidnightTimetable(Timetable):
    def infer_manual_data(self, run_after: float):
        return run_after
    def next_dagrun_info(self, last_automated: float | None, now: float) -> float:
        return [1]

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

Alast_automated + 3600

Bnow + 86400

C(now // 86400 + 1) * 86400

Dnow

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'now + 86400' which schedules at the same time next day, not midnight

Using 'last_automated + 3600' which is hourly from last run

Returning 'now' for immediate execution

The timetable should schedule the next run at midnight the next day (00:00 UTC). Using (now // 86400 + 1) * 86400 calculates the Unix timestamp for the start of the next day using integer division, where 86400 is the number of seconds in a day.

2fill in blank

medium

Complete the code to create a timetable that triggers every Monday at 9 AM.

Apache Airflow

from airflow.timetables.base import Timetable
from datetime import datetime, timedelta
class WeeklyMonday9AMTimetable(Timetable):
    def next_dagrun_info(self, last_automated: float | None, now: float) -> float:
        next_run = datetime.fromtimestamp(now).replace(hour=9, minute=0, second=0, microsecond=0)
        while next_run.weekday() != [1] or next_run.timestamp() <= now:
            next_run += timedelta(days=1)
        return next_run.timestamp()

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

A0

B4

C6

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1, which is Tuesday, not Monday

Confusing with systems where Sunday is 0

In Python's datetime.weekday() method, Monday is represented by 0, Tuesday by 1, ..., Sunday by 6. The code finds the next Monday at 9 AM after the current time.

3fill in blank

hard

Fix the error in the code to correctly calculate the next run time for a timetable that triggers every hour on the half hour.

Apache Airflow

from airflow.timetables.base import Timetable
from datetime import datetime, timedelta
class HourlyHalfHourTimetable(Timetable):
    def next_dagrun_info(self, last_automated: float | None, now: float) -> float:
        current = datetime.fromtimestamp(now)
        next_run = current.replace(minute=30, second=0, microsecond=0)
        if current.minute >= 30:
            next_run += timedelta(hours=[1])
        return next_run.timestamp()

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

A0

B1

C30

D60

Attempts:

3 left

💡 Hint

Common Mistakes

Adding 0 hours, leaving next_run in the past

Confusing minutes with hours (30 or 60)

If the current minute is 30 or greater, the half-hour mark today has passed, so advance to the next hour's half-hour by adding 1 hour.

4fill in blank

hard

Fill both blanks to create a timetable that triggers every weekday at 8 AM.

Apache Airflow

from airflow.timetables.base import Timetable
from datetime import datetime, timedelta
class Weekday8AMTimetable(Timetable):
    def next_dagrun_info(self, last_automated: float | None, now: float) -> float:
        next_run = datetime.fromtimestamp(now).replace(hour=[1], minute=0, second=0, microsecond=0)
        while next_run.timestamp() <= now or next_run.weekday() [2] 5:
            next_run += timedelta(days=1)
        return next_run.timestamp()

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

A8

B<

C>=

D7

Attempts:

3 left

💡 Hint

Common Mistakes

Setting hour to 7 or other value instead of 8

Using '< 5' which skips weekdays (Mon-Fri) instead of weekends

Set the hour to 8 for 8 AM. The loop continues while the time is not in the future or the day is a weekend (weekday() >= 5, where Sat=5, Sun=6), advancing to the next suitable weekday 8 AM.

5fill in blank

hard

Fill all three blanks to create a timetable that triggers on the first day of each month at midnight.

Apache Airflow

from airflow.timetables.base import Timetable
from datetime import datetime, timedelta
class MonthlyFirstDayMidnightTimetable(Timetable):
    def next_dagrun_info(self, last_automated: float | None, now: float) -> float:
        current = datetime.fromtimestamp(now)
        year = current.year
        month = current.month + [1]
        if month > 12:
            month = [2]
            year += 1
        next_run = datetime(year, month, [3], 0, 0, 0)
        return next_run.timestamp()

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

A1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 for day (invalid date)

Failing to reset month to 1 or increment year on overflow

Adding 0 instead of 1 to month

Add 1 to the current month for the next month. If it exceeds 12, reset month to 1 and increment the year. Use day 1 for the first day of the month, at midnight (hour=0).