Trigger a DAG Run via the Stable REST API fails with Bad Request due to external_trigger is set

[seybi87]

Apache Airflow version:

2.0.0

Environment:

• Cloud provider or hardware configuration: OpenStack -> VM -> Docker container
• OS (e.g. from /etc/os-release): Debian GNU/Linux 10 (buster)
• Kernel (e.g. uname -a): Linux 77f8efd77516 4.4.0-193-generic PrestoToMySqlTransfer #224-Ubuntu

What happened:

I am trying to trigger a DAG run via the new stable REST-API 1.0.0 by using a Java-based client. The Java client is generated from the Airflow OpenAPI specification with OpenAPI generator version 5.0.0 .

In Airflow I have one active DAG demo

I trigger the DAG execution via the java client with the following code snippet:

ApiClient defaultClient = Configuration.getDefaultApiClient();
defaultClient.setBasePath("http://1.2.3.4:8080/api/v1);
DagRunApi dagRunApi = new DagRunApi(defaultClient);
DAGRun dagRun = new DAGRun();
try {
      DAGRun result = dagRunApi.postDagRun("demo", dagRun);

      LOGGER.debug(result);

    } catch (ApiException e) {
      e.printStackTrace();
    }

However, I receive the following exception:

BAD REQUEST

What you expected to happen:

By checking the airflow logs it turned out that the external_trigger value of the DAGRun is set but this is actually a read-only value and not allowed to be set which results in the BAD REQUEST response.

Adding the nullable: true setting to the external_trigger and recreating the java client resolved the issue!

external_trigger:
          type: boolean
          nullable: true
          readOnly: true

How to reproduce it:

Create the Java client (probably any client will produce this error) via OpenAPI generator:

1. java -jar codegen/openapi-generator-cli-5.0.0.jar generate -i openapi.yaml -g java -o .
2. create a simple java class and apply the code snippets from above

[kaxil]

Not sure why it is giving you error, the default value is True:

airflow/airflow/api_connexion/schemas/dag_run_schema.py

Line 63 in 9d9ef1a

external_trigger = auto_field(default=True, dump_only=True)

airflow/airflow/api_connexion/openapi/v1.yaml

Lines 1553 to 1556 in 9d9ef1a

	external_trigger:
	type: boolean
	default: true
	readOnly: true

cc @ephraimbuddy @mik-laj

[seybi87]

The issues is caused because the external_trigger property is defined with default: true .
This results in an object DAGRun dagRun = new DAGRun(); that has set the external_trigger value yet the Airflow server API only accepts null values (as specified for the other DAGRun properties).

[mik-laj]

@kaxil This looks like an error in the generator. This field is marked read-only and should never be sent for POST requests in the request body. This should be fixed in the generator, not in the specification.

[kaxil]

@seybi87 Like @mik-laj said -- it looks like an error in generator as we already mark the field readOnly so we don't expect a value for it

[mik-laj]

OpenAPITools/openapi-generator#4190
It looks related.

[seybi87]

Yes, you are right, this should be handled by the generator. So feel free to close this issue.

Just out of curiosity, did you test the postDagRun call with the Airflow go client?

This would show if the error only occurs for the java client parts of code generator or for different languages.

[mik-laj]

Just out of curiosity, did you test the postDagRun call with the Airflow go client?

@houqp Can you check it?