dagline 0.0.8

Use Python's multiprocessing module to execute tasks(python functon and windows bat script) of a DAG in parallel

Overview

Dagline is a package for executing multiple tasks of a DAG flow in parallel. The type of task can be python function and Windows bat script.

System Requirements

• Python 3.10+

Installation

• python -m pip install dagline

Use-cases

• Create a folder where you put the dag files locally. You can name your folder/py whatever you want:
  dags\
          └──dag_example.py
   
• Define the DAG, open dag_example.py and enter the following content:

from dagline.models.dag import DAG
from dagline.models.operators.winbat import WinbatOperator
from dagline.models.operators.python import PythonOperator


def read_excel():
    '''Do your works here'''
    print('call this func read_excel')
    
def read_csv():
    '''Do your works here'''
    print('call this func read_csv')
    
def load_to_db():
    '''Do your works here'''
    print('call this func load_to_db')


task1 = PythonOperator(task_id = 'read_excel', python_callable = read_excel)
task2 = PythonOperator(task_id = 'read_csv', python_callable = read_csv)
task3 = PythonOperator(task_id = 'load_to_db', python_callable = load_to_db)
task4 = WinbatOperator(task_id = 'housekeep', bat_command = r"C:\xxx\housekeep.bat")


'''DAG graph, child task : [parent tasks]'''
tasks_flow ={
task1 : [],
task2 : [],
task3 : [task1, task2],
task4 : [task3]
}


with DAG(
    dag_id = 'dag_example',
    tasks_flow = tasks_flow,
    logfile = "C:\xxx\dag_example.log"
) as dag:
    pass

• Run a DAG in parallel or run a DAG from some specified tasks

python -m dagline dags run <dag_files_home> <dag_id> < --start_with_task_ids >
         dag_files_home                     The folder of the DAG files
         dag_id                                    The id of the dag
         --start_with_task_ids            A list of the task ids, if it was provided, the DAG will start from these tasks, not from the beginning of the DAG

>python -m dagline dags run C:\xxx\dags_tasks\dags dag_example1
>python -m dagline dags run C:\xxx\dags_tasks\dags dag_example1 --start_with_task_ids read_csv

• Run a task of the DAG

python -m dagline tasks run <dag_files_home> <dag_id> <task_id>
        dag_files_home                     The folder of the DAG files
        dag_id                                    The id of the dag
        task_id                                   The id of the task, only runs this task in the DAG

>python -m dagline tasks run C:\xxx\dags_tasks\dags dag_example read_csv

• Visualize  a DAG on the html page

python -m dagline dags show <dag_files_home> <dag_id>
        dag_files_home                     The folder of the DAG files
        dag_id                                    The id of the dag

>python -m dagline dags show C:\xxx\dags_tasks\dags dag_example