Source code for airflow.providers.amazon.aws.example_dags.example_athena

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#
#   http://www.apache.org/licenses/LICENSE-2.0
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from datetime import datetime, timedelta
from os import getenv

from airflow import DAG
from airflow.decorators import task
from airflow.providers.amazon.aws.hooks.s3 import S3Hook
from airflow.providers.amazon.aws.operators.athena import AWSAthenaOperator
from airflow.providers.amazon.aws.sensors.athena import AthenaSensor

# [START howto_operator_athena_env_variables]
S3_BUCKET = getenv("S3_BUCKET", "test-bucket")
S3_KEY = getenv("S3_KEY", "key")
ATHENA_TABLE = getenv("ATHENA_TABLE", "test_table")
ATHENA_DATABASE = getenv("ATHENA_DATABASE", "default")
# [END howto_operator_athena_env_variables]

SAMPLE_DATA = """"Alice",20
"Bob",25
"Charlie",30
"""
SAMPLE_FILENAME = 'airflow_sample.csv'
AWS_CONN_ID = 'aws_default'


@task(task_id='setup__add_sample_data_to_s3')
def add_sample_data_to_s3():
    s3_hook = S3Hook()
    s3_hook.load_string(SAMPLE_DATA, f'{S3_KEY}/{ATHENA_TABLE}/{SAMPLE_FILENAME}', S3_BUCKET, replace=True)


@task(task_id='teardown__remove_sample_data_from_s3')
def remove_sample_data_from_s3():
    s3_hook = S3Hook()
    if s3_hook.check_for_key(f'{S3_KEY}/{ATHENA_TABLE}/{SAMPLE_FILENAME}', S3_BUCKET):
        s3_hook.delete_objects(S3_BUCKET, f'{S3_KEY}/{ATHENA_TABLE}/{SAMPLE_FILENAME}')


@task(task_id='query__read_results_from_s3')
def read_results_from_s3(query_execution_id):
    s3_hook = S3Hook()
    if s3_hook.check_for_key(f'{S3_KEY}/{query_execution_id}.csv', S3_BUCKET):
        file_obj = s3_hook.get_conn().get_object(Bucket=S3_BUCKET, Key=f'{S3_KEY}/{query_execution_id}.csv')
        file_content = file_obj['Body'].read().decode('utf-8')
        print(file_content)
    else:
        print('Could not find QueryExecutionId:', query_execution_id)


QUERY_CREATE_TABLE = f"""
CREATE EXTERNAL TABLE IF NOT EXISTS {ATHENA_DATABASE}.{ATHENA_TABLE} ( `name` string, `age` int )
ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe'
WITH SERDEPROPERTIES ( 'serialization.format' = ',', 'field.delim' = ','
) LOCATION 's3://{S3_BUCKET}/{S3_KEY}/{ATHENA_TABLE}'
TBLPROPERTIES ('has_encrypted_data'='false')
"""

QUERY_READ_TABLE = f"""
SELECT * from {ATHENA_DATABASE}.{ATHENA_TABLE}
"""

QUERY_DROP_TABLE = f"""
DROP TABLE IF EXISTS {ATHENA_DATABASE}.{ATHENA_TABLE}
"""

with DAG(
    dag_id='example_athena',
    schedule_interval=None,
    start_date=datetime(2021, 1, 1),
    dagrun_timeout=timedelta(minutes=60),
    tags=['example'],
    catchup=False,
) as dag:
    # [START howto_athena_operator_and_sensor]

    # Using a task-decorated function to create a CSV file in S3
    add_sample_data_to_s3 = add_sample_data_to_s3()

    create_table = AWSAthenaOperator(
        task_id='setup__create_table',
        query=QUERY_CREATE_TABLE,
        database=ATHENA_DATABASE,
        output_location=f's3://{S3_BUCKET}/{S3_KEY}',
        sleep_time=30,
        max_tries=None,
        aws_conn_id=AWS_CONN_ID,
    )

    read_table = AWSAthenaOperator(
        task_id='query__read_table',
        query=QUERY_READ_TABLE,
        database=ATHENA_DATABASE,
        output_location=f's3://{S3_BUCKET}/{S3_KEY}',
        sleep_time=30,
        max_tries=None,
        aws_conn_id=AWS_CONN_ID,
    )

    get_read_state = AthenaSensor(
        task_id='query__get_read_state',
        query_execution_id="{{ task_instance.xcom_pull('query__read_table', key='return_value') }}",
        max_retries=None,
        sleep_time=10,
        aws_conn_id=AWS_CONN_ID,
    )

    # Using a task-decorated function to read the results from S3
    read_results_from_s3 = read_results_from_s3(
        "{{ task_instance.xcom_pull('query__read_table', key='return_value') }}"
    )

    drop_table = AWSAthenaOperator(
        task_id='teardown__drop_table',
        query=QUERY_DROP_TABLE,
        database=ATHENA_DATABASE,
        output_location=f's3://{S3_BUCKET}/{S3_KEY}',
        sleep_time=30,
        max_tries=None,
        aws_conn_id=AWS_CONN_ID,
    )

    # Using a task-decorated function to delete the S3 file we created earlier
    remove_sample_data_from_s3 = remove_sample_data_from_s3()

    (
        add_sample_data_to_s3
        >> create_table
        >> read_table
        >> get_read_state
        >> read_results_from_s3
        >> drop_table
        >> remove_sample_data_from_s3
    )
    # [END howto_athena_operator_and_sensor]