liminal/runners/airflow/tasks/job_start.py

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from liminal.runners.airflow.model import task
from liminal.runners.airflow.operators.job_status_operator import JobStartOperator


class JobStartTask(task.Task):
    """
    Job start task. Reports job start metrics.
    """

    def __init__(self, task_id, dag, parent, trigger_rule, liminal_config, pipeline_config,
                 task_config):
        super().__init__(task_id, dag, parent, trigger_rule, liminal_config, pipeline_config,
                         task_config)
        metrics = self.liminal_config.get('metrics', {})
        self.metrics_namespace = metrics.get('namespace', '')
        self.metrics_backends = metrics.get('backends', [])

    def apply_task_to_dag(self):
        job_start_task = JobStartOperator(
            task_id='start',
            namespace=self.metrics_namespace,
            application_name=self.pipeline_config['pipeline'],
            backends=self.metrics_backends,
            dag=self.dag,
            trigger_rule=self.trigger_rule
        )

        if self.parent:
            self.parent.set_downstream(job_start_task)

        return job_start_task