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Task Management, Scheduling, and Alerting.

Admin commands are accessed via the tf command line tool. See tf --help for complete usage.

Setup

For task decorators:

pip install taskflows

For additional service/scheduling functionality:

sudo apt install libdbus-glib-1-dev
loginctl enable-linger
pip install taskflows[service]

Task execution metadata is stored in SQLite (default) or Postgresql. To use a personal database, set environment variable TASKFLOWS_DB_URL to your database URL. If using Postgresql, TASKFLOWS_DB_SCHEMA may also be set to use a custom schema (default schema is taskflows).

Create Tasks

Turn any function (optionally async) into a task that logs metadata to the database and sends alerts, allows retries, etc..

alerts=[
    Alerts(
        send_to=[   
            Slack(
                bot_token=os.getenv("SLACK_BOT_TOKEN"),
                channel="critical_alerts"
            ),
            Email(
                addr="[email protected]", 
                password=os.getenv("EMAIL_PWD"),
                receiver_addr=["[email protected]", "[email protected]"]
            )
        ],
        send_on=["start", "error", "finish"]
    )
]
@task(
    name='some-task',
    required=True,
    retries=1,
    timeout=30,
    alerts=alerts
)
async def hello():
    print("Hi.")

Review Task Status/Results

Tasks can send alerts via Slack and/or Email, as shown in the above example. Internally, alerts are sent using the alert-msgs package.
Task start/finish times, status, retry count, return values can be found in the task_runs table.
Any errors that occurred during the execution of a task can be found in the task_errors table.

Create Services

Note: To use services, your system must have systemd (the init system on most modern Linux distributions)

Services run commands on a specified schedule. See Service for service configuration options.

To create the service(s), use the create method (e.g. srv.create()), or use the CLI create command (e.g. taskflows create my_services.py)

Examples

from taskflows import Calendar, Service

Run at specified calendar days/time.

see Calendar for more options.

srv = Service(
    name="something",
    start_command="docker start something",
    start_schedule=Calendar("Mon-Sun 14:00 America/New_York"),
)

Run command once at half an hour from now.

run_time = datetime.now() + timedelta(minutes=30)
srv = Service(
    name='write-message',
    start_command="bash -c 'echo hello >> hello.txt'",
    start_schedule=Calendar.from_datetime(run_time),
)

Run command after system boot, then again every 5 minutes after start of previous run. Skip run if CPU usage is over 80% for the last 5 minutes.

see Periodic and constraints for more options.

Service(
    name="my-periodic-task",
    start_command="docker start something",
    start_schedule=Periodic(start_on="boot", period=60*5, relative_to="start"),
    system_load_constraints=CPUPressure(max_percent=80, timespan="5min", silent=True)
)