Yeah it does seem that templating does not work with expanded params at the
moment. No promises but I would bet this will change at some point. Seems
reasonable and I can't think of a technical problem.
Tal's approach looks good. I came up with basically the same thing when
testing this out:
@dag.task
def gen_vars(ds=None):
return [{"MY_VAR": ds} for x in range(3)]
op2 = BashOperator.partial(task_id='task_mapped', bash_command="echo
$MY_VAR",).expand(
env=gen_vars(),
)
One thing I noticed in your example was, it appears, maybe you are mapping
from two upstream tasks, for two mapped arguments. You may have noticed,
this will result in a cartesian product (maybe this is desirable for
you?). This is an area we are actively working on, so that you can provide
multiple kwargs to map from a single task.
On Wed, Jun 15, 2022 at 3:36 AM Tal Nagar <tal.na...@evogene.com> wrote:
> Hi Joe
>
> Not sure if it's the recommended way to do it, however what worked for me
> is rendering the templates in a python task and not directly in the
> KubernetesPodOperator.
>
> For example:
>
>
>
> @task()
>
> def create_cmds(**context):
>
> run_params = context["params"]
>
> size = int(run_params['size'])
>
> arr = []
>
> for s in range(int(size)):
>
> arr.append([f'echo hi {s}'])
>
> return arr
>
>
>
> say_hi = KubernetesPodOperator.partial(
>
> image="alpine",
>
> cmds=["/bin/sh", "-c"],
>
> task_id='test',
>
> name='test'
>
> ).expand(arguments=create_cmds())
>
>
>
> *From:* Joe Auty <joea...@gmail.com>
> *Sent:* Tuesday, June 14, 2022 10:03 AM
> *To:* users@airflow.apache.org
> *Subject:* Templated fields and dynamic task mapping
>
>
>
> Hello,
>
> I'm trying to understand the docs here:
> https://airflow.apache.org/docs/apache-airflow/2.3.2/concepts/dynamic-task-mapping.html#how-do-templated-fields-and-mapped-arguments-interact
> , specifically this section:
>
>
> If you want to interpolate values either call task.render_template yourself,
> or use interpolation:
>
>
> In the example in the previous section of what doesn't work we have:
>
> printer.expand(val=make_list())
>
>
> What should the corrected version of this line be? IOW, how would I call
> make_list passing in the context so that I can send templated fields to my
> mapping function? Here is a more specific use case:
>
>
> KubernetesPodOperator.partial(
> task_id="schema-dump-input",
> namespace=NAMESPACE,
> image=REGISTRY_URL + "/postgres-client:12",
> name="pg-schemadump",
> in_cluster=True,
> hostnetwork=False,
> max_active_tis_per_dag=1,
> dag=dag
> ).expand(
> cmds=schema_dump_input_cmds(ds),
> env_vars=schema_dump_input_env_vars(ds)
> )
>
> In this example, ds has no value of course because it is not defined
> anywhere, and of course {{ ds }} doesn't work either (this doesn't get
> interpolated and is registered as literally "{{ ds }}"). How can I pass in
> a templated field, such as {{ ds }}?
>
> Thanks very much in advance!
>
>
>
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