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ckanext-aircan

A CKAN extension for integrating the AirFlow-based AirCan Data Factory into CKAN. Specifically, this extension provides:

  • New APIs in CKAN for triggering and monitoring workflows (DAGs) in AirFlow
  • Hooking key events in CKAN into the AirFlow instance. Specifically, resource creation and update trigger DAGs in AirFlow to load resource data into the DataStore. See https://tech.datopian.com/load/#ckan-v3

Installation

Basic Setup

There are two potential cases:

Configuration

  • Enable the extension in CKAN by adding the plugin aircan_connector to CKAN__PLUGINS list in your.env. Make sure to disable datapusher and xloader if you have them there as AirCan replaces them.
  • Add details of the AirFlow instance -- details below for Local case and Cloud case

Local Airflow instance

  • In your.env file add CKAN__AIRFLOW__URL according to Apache AirFlow REST API Reference. If you are running CKAN in a Docker container, make sure to specify the Airflow URL with host.docker.internal instead of localhost: CKAN__AIRFLOW__URL=http://host.docker.internal:8080/api/experimental/dags/ckan_api_load_multiple_steps/dag_runs. Also notice Airflow requires, by default, the endpoint api/experimental/dags/DAG_ID for API access.
  • Add Airflow admin username and password for authorization: CKAN__AIRFLOW__USERNAME=airflow_amin_username and CKAN__AIRFLOW__PASSWORD=airflow_admin_password
  • Also in your .env file, specify a temporary directory for files: CKAN__AIRFLOW__STORAGE_PATH=/tmp/ and CKAN__AIRFLOW__CLOUD=local.

Airflow instance on Google Composer

Assuming you already have a Google Cloud Composer properly set up, it is possible to trigger a DAG on GoogleCloud Platform following these steps:

  • Download your credentials file (a JSON file) from Google Cloud Platform. Convert it to a single-line JSON.

  • Set up the following environment variables on your .env file:

    CKAN__AIRFLOW__CLOUD=GCP # this line activates the integration with GCP
CKAN__AIRFLOW__CLOUD__PROJECT_ID=YOUR_PROJECT_ID_ON_COMPOSER
CKAN__AIRFLOW__CLOUD__LOCATION=us-east1_OR_OTHER
CKAN__AIRFLOW__CLOUD__COMPOSER_ENVIRONMENT=NAME_OF_COMPOSER_ENVIRONMENT
CKAN__AIRFLOW__CLOUD__WEB_UI_ID=ID_FROM_AIRFLOW_UI_ON_COMPOSER
CKAN__AIRFLOW__CLOUD__GOOGLE_APPLICATION_CREDENTIALS={ YOUR SINGLE LINE CREDENTIALS JSON FILE }

Getting Started

Triggering a Workflow (DAG)

Make a request to http://YOUR-CKAN:5000/api/3/action/aircan_submit?dag_name=DAG_NAME, specifying your CKAN_API_KEY on the header and send the following information on the body of the request, replacing the values accordingly:

{
  "package_id": "YOUR_PACKAGE_ID",
  "url":  "http://url.for.your.resource.com",
  "description": "This is the best resource ever!" ,
  "schema": {
    "fields":  [
          {
            "name": "FID",
            "type": "int",
            "format": "default"
          },
          {
            "name": "another-field",
            "type": "float",
            "format": "default"
          }
        ]
  }
}

Replace dag_name with the DAG you want to invoke, for example, http://YOUR-CKAN:5000/api/3/action/aircan_submit?dag_name=ckan_api_load_gcp. This will trigger the DAG ckan_api_load_gcp.

NB: the DAG ckan_api_load_gcp is designed for Google Cloud Composer AirFlow instance and will load a resource into the DataStore.

The endpoint http://YOUR-CKAN:5000/api/3/action/resource_create produces the same effect of http://YOUR-CKAN:5000/api/3/action/aircan_submit?dag_name=DAG_NAME. Make sure you set up an extra variable on your .env file specifying the DAG you want to trigger:

# .env
# all other variables
CKAN__AIRFLOW__CLOUD__DAG_NAME=DAG_YOU_WANT_TO_TRIGGER

For CKAN Datastore data loader dag

  • Add ckanext.aircan.load_with_postgres_copy=True env to load with postgres copy loader. By default it loads with datastore API.
  • Add ckanext.aircan.datastore_chunk_insert_rows_size=300 env variable to configure number of records to send a request to datastore. Default 250 rows.
  • addd append_or_update_datastore = true if new data schema matches with old schema append or update data, otherwise create new table
  • add ckanext.aircan.enable_datastore_upload_configuration=true to enable the upload configuration UI option.
  • add ckanext.aircan.notification_to = author, maintainer, editor, [email protected] failure email notification sent to.
  • add ckanext.aircan.notification_from = [email protected] failure notification from email.
  • add ckanext.aircan.notification_subject configure notification subject.

Update aircan run status

The aircan_status_update API can be use to store or update the run status for given resource. It accepts the POST request with authorized user.

{ 
    "resource_id": "a4a520aa-c790-4b53-93aa-de61e1a2813c",
    "state": "progress",
    "message":"Pusing dataset records.",
    "dag_run_id":"394a1f0f-d8b3-47f2-9a51-08732349b785",
    "error": {
        "message" : "Failed to push data records."
    }
}

Retrieving aircan run status

Use aircan_status API to get aircan run status for given resource providing resource id. eg. http://YOUR-CKAN:5000/api/3/action/aircan_status

{
  "resource_id": "a4a520aa-c790-4b53-93aa-de61e1a2813c"
}

Tests with Cypress

Test the aircan-connector with cypress.

Installation

npm install

Running

Opens up the cypress app and you can choose the specs to run.

npm test