Source code for airflow.providers.amazon.aws.operators.emr_add_steps
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import ast
from typing import Any, Dict, List, Optional, Union
from airflow.exceptions import AirflowException
from airflow.models import BaseOperator
from airflow.providers.amazon.aws.hooks.emr import EmrHook
from airflow.utils.decorators import apply_defaults
[docs]class EmrAddStepsOperator(BaseOperator):
"""
An operator that adds steps to an existing EMR job_flow.
:param job_flow_id: id of the JobFlow to add steps to. (templated)
:type job_flow_id: Optional[str]
:param job_flow_name: name of the JobFlow to add steps to. Use as an alternative to passing
job_flow_id. will search for id of JobFlow with matching name in one of the states in
param cluster_states. Exactly one cluster like this should exist or will fail. (templated)
:type job_flow_name: Optional[str]
:param cluster_states: Acceptable cluster states when searching for JobFlow id by job_flow_name.
(templated)
:type cluster_states: list
:param aws_conn_id: aws connection to uses
:type aws_conn_id: str
:param steps: boto3 style steps or reference to a steps file (must be '.json') to
be added to the jobflow. (templated)
:type steps: list|str
:param do_xcom_push: if True, job_flow_id is pushed to XCom with key job_flow_id.
:type do_xcom_push: bool
"""
[docs] template_fields = ['job_flow_id', 'job_flow_name', 'cluster_states', 'steps']
[docs] template_ext = ('.json',)
@apply_defaults
def __init__(
self,
*,
job_flow_id: Optional[str] = None,
job_flow_name: Optional[str] = None,
cluster_states: Optional[List[str]] = None,
aws_conn_id: str = 'aws_default',
steps: Optional[Union[List[dict], str]] = None,
**kwargs,
):
if kwargs.get('xcom_push') is not None:
raise AirflowException("'xcom_push' was deprecated, use 'do_xcom_push' instead")
if not (job_flow_id is None) ^ (job_flow_name is None):
raise AirflowException('Exactly one of job_flow_id or job_flow_name must be specified.')
super().__init__(**kwargs)
cluster_states = cluster_states or []
steps = steps or []
self.aws_conn_id = aws_conn_id
self.job_flow_id = job_flow_id
self.job_flow_name = job_flow_name
self.cluster_states = cluster_states
self.steps = steps
[docs] def execute(self, context: Dict[str, Any]) -> List[str]:
emr_hook = EmrHook(aws_conn_id=self.aws_conn_id)
emr = emr_hook.get_conn()
job_flow_id = self.job_flow_id or emr_hook.get_cluster_id_by_name(
str(self.job_flow_name), self.cluster_states
)
if not job_flow_id:
raise AirflowException(f'No cluster found for name: {self.job_flow_name}')
if self.do_xcom_push:
context['ti'].xcom_push(key='job_flow_id', value=job_flow_id)
self.log.info('Adding steps to %s', job_flow_id)
# steps may arrive as a string representing a list
# e.g. if we used XCom or a file then: steps="[{ step1 }, { step2 }]"
steps = self.steps
if isinstance(steps, str):
steps = ast.literal_eval(steps)
response = emr.add_job_flow_steps(JobFlowId=job_flow_id, Steps=steps)
if not response['ResponseMetadata']['HTTPStatusCode'] == 200:
raise AirflowException(f'Adding steps failed: {response}')
else:
self.log.info('Steps %s added to JobFlow', response['StepIds'])
return response['StepIds']