# Airflow

## Prerequisites

Ensure the following variables are configured in the Airflow environment:

* **`airflow_url`**: Base URL of the Airflow server.
* **`airflow_dag_id`**: Identifier of the DAG to be triggered.

{% hint style="info" %}
**Note:** While you can directly use the target URL, we strongly recommend leveraging variables and secrets for enhanced security and maintainability.
{% endhint %}

## Authentication

For Airflow authentication, a Base64-encoded token is required:

* Generate the token using the string `username:password`.
* Example command to generate the token:

  ```bash
  echo -n "username:password" | base64
  ```
* Store this token securely as a secret named **`airflow_base64_token`**.

## Triggering a DAG

When a registered job in Erathos successfully completes, the specified DAG will be triggered with the following parameters:

* **`schema_name`**: Name of the related schema.
* **`table_name`**: Name of the related table.

POST Payload:

```json
{
  "description": "Trigger Airflow DAG run on success job execution",
  "is_active": true,
  "method": "POST",
  "url": "https://${{variables.airflow_url}}/api/v1/dags/${{variables.airflow_dag_id}}/dagRuns",
  "header": {
    "Authorization": "Basic ${{secrets.airflow_base64_token}}" 
  },
  "body": {
    "conf": {
      "schema": "${{erathos.schema_name}}",
      "table": "${{erathos.table_name}}"
    },
    "note": "triggered on Erathos platform by ${{erathos.triggered_by}}"
  },
  "rules": [
    {
      "variable_name": "STATUS",
      "operation": "EQUAL",
      "value": "FINISHED"
    },
  ],
  "jobs": [
    "<ERATHOS_JOB1_ID>",
    "<ERATHOS_JOB2_ID>",
    ...
    "<ERATHOS_JOBN_ID>"
  ]
}
```