cronevents 0.0.44

A package to run cron jobs(events)

Cron Events

This module provides a way to schedule recurring events using a cron-like syntax. Events can be scheduled to run at specific intervals or at specific times on specific days.

Table of Contents

• Installation
• Learn by Example
• Configuration
• License

Installation

pip install cronevents

Learn by Example

"""Cron-like event scheduling module.

This module provides a way to schedule recurring events using a cron-like syntax.
Events can be scheduled to run at specific intervals or at specific times on specific days.

Syntax:
    '(`every` | `in` | `on`) (`Weekday` | `n unit [n unit ...]`) [@ hh[:mm[:ss]] ["am" | "pm"]] [Timezone]'

    Combine multiple schedules with `||`:
    'every Monday @ 9:00 am || every Friday @ 5:00 pm'

Examples:
    'every 2 days @ 10:00:00 pm'
    'every Monday @ 23'
    'every 5 seconds'
    'every 2 days 1 hours 23 minutes 2 seconds'
    'every 1 days @ 9:00 am America/New_York'

Note:
    Using '@' will run the event at least once a day.
    Timezone defaults to UTC. Append any IANA timezone name (e.g. America/New_York)
    or a custom abbreviation registered with add_timezone_abbr().
"""

# Uncomment to register events to the event manager
# import os
# os.environ['REGISTER_CRON_EVENT'] = 'true'

from cronevents.event_manager import event, add_timezone_abbr


@event('every 31 seconds')
def test():
    """Write 'test' to a file and print it every 31 seconds."""
    with open('test.txt', 'a') as f:
        f.write('test\n')
    print('test')


@event('every 2 days 1 hours 23 minutes 2 seconds')
def test2():
    """Write 'test2' to a file and print 'test2' every 2 days, 1 hour, 23 minutes, and 2 seconds."""
    with open('test.txt', 'a') as f:
        f.write('test2\n')
    print('test2')


@event('every 1 days @ 2:00 pm')
def test3():
    """Write 'test3' to a file and print it daily at 2:00 PM."""
    with open('test.txt', 'a') as f:
        f.write('test3\n')
    print('test3')


@event('every Friday')
def test4():
    """Write 'test4' to a file and print it every Friday."""
    with open('test.txt', 'a') as f:
        f.write('test4\n')
    print('test4')


@event('every Tuesday @ 3:00')
def test5():
    """Write 'test5' to a file and print it every Tuesday at 3:00 AM."""
    with open('test.txt', 'a') as f:
        f.write('test5\n')
    print('test5')


# Use a full IANA timezone name appended to the query
@event('every 1 days @ 9:00 am America/New_York')
def test6():
    """Write 'test6' to a file and print it daily at 9:00 AM Eastern time."""
    with open('test.txt', 'a') as f:
        f.write('test6\n')
    print('test6')


# Or register a custom abbreviation and use that instead
add_timezone_abbr('America/Los_Angeles', 'PT')

@event('every Monday @ 8:00 am PT')
def test7():
    """Write 'test7' to a file and print it every Monday at 8:00 AM Pacific time."""
    with open('test.txt', 'a') as f:
        f.write('test7\n')
    print('test7')

Configuration

On first run, cronevents auto-creates a settings file at .cronevents/settings.yaml with the defaults shown below. Edit this file to change backends or toggle logging. The file location can be overridden with the CRONEVENTS_SETTINGS_PATH environment variable.

Default settings.yaml

log_cronevents_triggers: true   # record every time an event fires
log_cronevents_processes: false # capture stdout/stderr of event subprocesses

cronevents:                     # where registered events are stored
  module: cronevents.db.cronevents.sqlite
  name: Sqlite3CronEventsDb

logger:                         # how subprocess output is stored (when log_cronevents_processes: true)
  module: cronevents.db.logs.file
  name: FileLogger

trigger:                        # where trigger history is stored (when log_cronevents_triggers: true)
  module: cronevents.db.triggers.sqlite
  name: Sqlite3TriggerDb

How It Works

When anything imports from cronevents, get_settings() is called lazily on first use. It reads settings.yaml (or creates it if missing), then constructs a Settings object. Each of the three backend keys (cronevents, logger, trigger) is a module/name pair pointing to a class that cronevents will import and instantiate at runtime. If the class can't be loaded for any reason, it falls back to the SQLite/file defaults.

Using PostgreSQL Backends

Switch any or all backends to Postgres by updating settings.yaml:

log_cronevents_triggers: true
log_cronevents_processes: true

cronevents:
  module: cronevents.db.cronevents.postgres
  name: PostgresCronEventsDb

logger:
  module: cronevents.db.logs.postgres
  name: PostgresLogger

trigger:
  module: cronevents.db.triggers.postgres
  name: PostgresTriggerDb

The Postgres backends read connection details from environment variables (or a .env file):

Variable	Default
POSTGRES_HOST	localhost
POSTGRES_PORT	5432
POSTGRES_USER	—
POSTGRES_PASSWORD	—
POSTGRES_DATABASE	—

Custom Backends

You can point any backend at your own class — just subclass the appropriate base and reference it in settings.yaml.

Custom event store — subclass CronEventsDbBase:

# myproject/my_store.py
from cronevents.db.cronevents.base import CronEventsDbBase, CronEvent

class MyCronEventsDb(CronEventsDbBase):
    def insert(self, cronevent: CronEvent) -> None: ...
    def update(self, cronevent: CronEvent) -> None: ...
    def upsert(self, cronevent: CronEvent) -> None: ...
    def delete(self, cronevent_id: str) -> None: ...
    def get(self, cronevent_id=None, module=None, func=None) -> CronEvent | None: ...
    def list(self) -> list[CronEvent]: ...

Custom logger — subclass LoggerBase:

# myproject/my_logger.py
from cronevents.db.logs.base import LoggerBase, Log

class MyLogger(LoggerBase):
    def __init__(self, trigger_id: str): ...
    def log(self, log: str): ...
    def __exit__(self, exc_type, exc_val, exc_tb): ...
    def list(self, stream: bool = False) -> list[Log]: ...

Custom trigger store — subclass TriggerDbBase:

# myproject/my_triggers.py
from cronevents.db.triggers.base import TriggerDbBase, Trigger

class MyTriggerDb(TriggerDbBase):
    def insert(self, trigger: Trigger): ...
    def upsert(self, trigger: Trigger): ...
    def list(self, stream=False, cronevent_id=None) -> list[Trigger]: ...

Then reference your class in settings.yaml:

cronevents:
  module: myproject.my_store
  name: MyCronEventsDb

logger:
  module: myproject.my_logger
  name: MyLogger

trigger:
  module: myproject.my_triggers
  name: MyTriggerDb

Environment Variables

Variable	Default	Description
CRONEVENTS_SETTINGS_PATH	.cronevents/settings.yaml	Path to the settings file
CRONEVENTS_LOG_DIR	.cronevents/logs	Directory for file-based process logs
REGISTER_CRON_EVENT	false	Set to true to register events on import
POSTGRES_HOST	localhost	Postgres host (Postgres backends only)
POSTGRES_PORT	5432	Postgres port
POSTGRES_USER	—	Postgres user
POSTGRES_PASSWORD	—	Postgres password
POSTGRES_DATABASE	—	Postgres database name

License

• MIT License