Initial empty airflow project

2025-02-09 20:08:12 +00:00
parent fd4585a9c5
commit 48126aeef2
11 changed files with 362 additions and 0 deletions
--- a/dags/exampledag.py
+++ b/dags/exampledag.py
@@ -0,0 +1,100 @@
+"""
+## Astronaut ETL example DAG
+
+This DAG queries the list of astronauts currently in space from the
+Open Notify API and prints each astronaut's name and flying craft.
+
+There are two tasks, one to get the data from the API and save the results,
+and another to print the results. Both tasks are written in Python using
+Airflow's TaskFlow API, which allows you to easily turn Python functions into
+Airflow tasks, and automatically infer dependencies and pass data.
+
+The second task uses dynamic task mapping to create a copy of the task for
+each Astronaut in the list retrieved from the API. This list will change
+depending on how many Astronauts are in space, and the DAG will adjust
+accordingly each time it runs.
+
+For more explanation and getting started instructions, see our Write your
+first DAG tutorial: https://www.astronomer.io/docs/learn/get-started-with-airflow
+
+![Picture of the ISS](https://www.esa.int/var/esa/storage/images/esa_multimedia/images/2010/02/space_station_over_earth/10293696-3-eng-GB/Space_Station_over_Earth_card_full.jpg)
+"""
+
+from airflow import Dataset
+from airflow.decorators import dag, task
+from pendulum import datetime
+import requests
+
+
+# Define the basic parameters of the DAG, like schedule and start_date
+@dag(
+    start_date=datetime(2024, 1, 1),
+    schedule="@daily",
+    catchup=False,
+    doc_md=__doc__,
+    default_args={"owner": "Astro", "retries": 3},
+    tags=["example"],
+)
+def example_astronauts():
+    # Define tasks
+    @task(
+        # Define a dataset outlet for the task. This can be used to schedule downstream DAGs when this task has run.
+        outlets=[Dataset("current_astronauts")]
+    )  # Define that this task updates the `current_astronauts` Dataset
+    def get_astronauts(**context) -> list[dict]:
+        """
+        This task uses the requests library to retrieve a list of Astronauts
+        currently in space. The results are pushed to XCom with a specific key
+        so they can be used in a downstream pipeline. The task returns a list
+        of Astronauts to be used in the next task.
+        """
+        try:
+            r = requests.get("http://api.open-notify.org/astros.json")
+            r.raise_for_status()
+            number_of_people_in_space = r.json()["number"]
+            list_of_people_in_space = r.json()["people"]
+        except:
+            print("API currently not available, using hardcoded data instead.")
+            number_of_people_in_space = 12
+            list_of_people_in_space = [
+                {"craft": "ISS", "name": "Oleg Kononenko"},
+                {"craft": "ISS", "name": "Nikolai Chub"},
+                {"craft": "ISS", "name": "Tracy Caldwell Dyson"},
+                {"craft": "ISS", "name": "Matthew Dominick"},
+                {"craft": "ISS", "name": "Michael Barratt"},
+                {"craft": "ISS", "name": "Jeanette Epps"},
+                {"craft": "ISS", "name": "Alexander Grebenkin"},
+                {"craft": "ISS", "name": "Butch Wilmore"},
+                {"craft": "ISS", "name": "Sunita Williams"},
+                {"craft": "Tiangong", "name": "Li Guangsu"},
+                {"craft": "Tiangong", "name": "Li Cong"},
+                {"craft": "Tiangong", "name": "Ye Guangfu"},
+            ]
+
+        context["ti"].xcom_push(
+            key="number_of_people_in_space", value=number_of_people_in_space
+        )
+        return list_of_people_in_space
+
+    @task
+    def print_astronaut_craft(greeting: str, person_in_space: dict) -> None:
+        """
+        This task creates a print statement with the name of an
+        Astronaut in space and the craft they are flying on from
+        the API request results of the previous task, along with a
+        greeting which is hard-coded in this example.
+        """
+        craft = person_in_space["craft"]
+        name = person_in_space["name"]
+
+        print(f"{name} is currently in space flying on the {craft}! {greeting}")
+
+    # Use dynamic task mapping to run the print_astronaut_craft task for each
+    # Astronaut in space
+    print_astronaut_craft.partial(greeting="Hello! :)").expand(
+        person_in_space=get_astronauts()  # Define dependencies using TaskFlow API syntax
+    )
+
+
+# Instantiate the DAG
+example_astronauts()