Fix missing get_backup method for Dataproc Metastore

[potiuk]

Found during #19891 fixing (yay! MyPy actually found some real errors).

The get_backup method was missing in Dataproc Metastore
implementation.

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[potiuk]

Yay! Found a real error thanks to MyPY :)

[github-actions]

The PR is likely OK to be merged with just subset of tests for default Python and Database versions without running the full matrix of tests, because it does not modify the core of Airflow. If the committers decide that the full tests matrix is needed, they will add the label 'full tests needed'. Then you should rebase to the latest main or amend the last commit of the PR, and push it with --force-with-lease.

[lwyszomi]

@potiuk what errors we had without this? because we didn't add this method intentionally.

[potiuk]

Why Intentionally? It does not look like this was intentional, because it has been called in the operator (in case of error, but it was). It could be that there was another mistake in the operator that called this method - but this did seem like a missing method that is used elsewhere?

airflow/airflow/providers/google/cloud/operators/dataproc_metastore.py

Line 138 in 837ff7e

backup = hook.get_backup(

        except HttpError as err:
            if err.resp.status not in (409, '409'):
                raise
            self.log.info("Backup %s already exists", self.backup_id)
            backup = hook.get_backup(
                project_id=self.project_id,
                region=self.region,
                service_id=self.service_id,
                backup_id=self.backup_id,
                retry=self.retry,
                timeout=self.timeout,
                metadata=self.metadata,
            )
        return Backup.to_dict(backup)

What do you think is the right fix @lwyszomi ? Should id be replaced with something else here?

[potiuk]

BTW: we still have a chance to fix it today as I am preparing to publish RC2 for providers - so if this is wrong - it would be great to get a better fix today.

[potiuk]

BTW ^^ this is what MyPy discovered :). I have no such hawk-eye :)

[lwyszomi]

@potiuk We decided that we should not have a operator for this hook method, I didn't know that we using this in the create backup operator. I don't know how this happen and we didn't discovered this in the tests.

This is really good fix to add this method to the hook.

[potiuk]

Cool :)

[potiuk]

Thank MyPy for that, not me :). I merely followed MyPy screaming " pleeeeease add the method " at me.