External files in Airflow DAG

Question

I’m trying to access external files in a Airflow Task to read some sql, and I’m getting “file not found”. Has anyone come across this?

from airflow import DAG
from airflow.operators.python_operator import PythonOperator
from datetime import datetime, timedelta

dag = DAG(
    'my_dat',
    start_date=datetime(2017, 1, 1),
    catchup=False,
    schedule_interval=timedelta(days=1)
)

def run_query():
    # read the query
    query = open('sql/queryfile.sql')
    # run the query
    execute(query)

tas = PythonOperator(
    task_id='run_query', dag=dag, python_callable=run_query)

The log state the following:

IOError: [Errno 2] No such file or directory: 'sql/queryfile.sql'

I understand that I could simply copy and paste the query inside the same file, it’s really not at neat solution. There are multiple queries and the text is really big, embed it with the Python code would compromise readability.

Asked By: Alessandro Mariani

||

Source

Answer 1

All relative paths are taken in reference to the AIRFLOW_HOME environment variable. Try:

Giving absolute path
place the file relative to AIRFLOW_HOME
try logging the PWD in the python callable and then decide what path to give (Best option)

Answered By: Priyank Mehta

Answer 2

Here is an example use Variable to make it easy.

First add Variable in Airflow UI -> Admin -> Variable, eg. {key: 'sql_path', values: 'your_sql_script_folder'}
Then add following code in your DAG, to use Variable from Airflow you just add.

DAG code:

import airflow
from airflow.models import Variable

tmpl_search_path = Variable.get("sql_path")

dag = airflow.DAG(
   'tutorial',
    schedule_interval="@daily",
    template_searchpath=tmpl_search_path,  # this
    default_args=default_args
)

Now you can use sql script name or path under folder Variable
You can learn more in this

Answered By: zhongjiajie

Answer 3

Assuming that the sql directory is relative to the current Python file, you can figure out the absolute path to the sql file like this:

import os

CUR_DIR = os.path.abspath(os.path.dirname(__file__))

def run_query():
    # read the query
    query = open(f"{CUR_DIR}/sql/queryfile.sql")
    # run the query
    execute(query)

Answered By: Jake

Answer 4

you can get DAG directory like below.

conf.get('core', 'DAGS_FOLDER')

# open file
open(os.path.join(conf.get('core', 'DAGS_FOLDER'), 'something.json'), 'r')

ref: https://airflow.apache.org/docs/apache-airflow/stable/configurations-ref.html#dags-folder

Answered By: tsugitta

External files in Airflow DAG

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