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digitalmars.D - Task Scheduler / Task Queues/Cron jobs tool

Mara (https://github.com/mara/data-integration) is a task 
scheduler.. you define chain-able tasks to be scheduled for 
execution with support for sub-tasks. There's an Apache version 
called Airflow initially started at AirBnB.

Came across it on HackerNews 

Will be really useful to have something like this in D (scripted 
in D). Such a tool is used by several major enterprises per the 
Airflow docs (https://github.com/apache/airflow). A potential 
killer app that's actually needed for enterprise workflow.

Its like (Mara in Python):
from data_integration.commands.bash import RunBash
from data_integration.pipelines import Pipeline, Task
from data_integration.ui.cli import run_pipeline, 

pipeline = Pipeline(
     description='A small pipeline that demonstrates the interplay 
between pipelines, tasks and commands')

pipeline.add(Task(id='ping_localhost', description='Pings 
                   commands=[RunBash('ping -c 3 localhost')]))

sub_pipeline = Pipeline(id='sub_pipeline', description='Pings a 
number of hosts')

for host in ['google', 'amazon', 'facebook']:
     sub_pipeline.add(Task(id=f'ping_{host}', description=f'Pings 
                           commands=[RunBash(f'ping -c 3 

sub_pipeline.add_dependency('ping_amazon', 'ping_facebook')
sub_pipeline.add(Task(id='ping_foo', description='Pings foo',
                       commands=[RunBash('ping foo')]), 

pipeline.add(sub_pipeline, ['ping_localhost'])

pipeline.add(Task(id='sleep', description='Sleeps for 2 seconds',
                   commands=[RunBash('sleep 2')]), 

Another one in Node.JS is Agenda 

If you work in an enterprise with lots of scheduled cron 
jobs/task queues that sometimes depend on each other...and you 
need transparency and metrics, that's your tool.
Jul 12 2019