[AIRFLOW-6432] Raise appropriate exception in EmrAddStepsOperator when using job_flow_name and no cluster is found

[aviemzur]

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Jira

• My PR addresses the following Airflow Jira issues and references them in the PR title. For example, "[AIRFLOW-6432] My Airflow PR"
  • https://issues.apache.org/jira/browse/AIRFLOW-6432
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Description

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This PR fiixes EmrAddStepsOperator broken ref & faulty test

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:
  Fix in tests.contrib.operators.test_emr_add_steps_operator.TestEmrAddStepsOperator#test_init_with_cluster_name

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  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

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[codecov-io]

Codecov Report

Merging #6898 into master will decrease coverage by 0.07%.
The diff coverage is 85.71%.

@@            Coverage Diff             @@
##           master    #6898      +/-   ##
==========================================
- Coverage   84.62%   84.54%   -0.08%     
==========================================
  Files         679      679              
  Lines       38505    38618     +113     
==========================================
+ Hits        32584    32650      +66     
- Misses       5921     5968      +47

Impacted Files	Coverage Δ
...irflow/contrib/operators/emr_add_steps_operator.py	91.42% <100%> (+0.25%)	⬆️
airflow/contrib/hooks/emr_hook.py	93.75% <66.66%> (+0.2%)	⬆️
airflow/contrib/hooks/cassandra_hook.py	0% <0%> (-100%)	⬇️
airflow/kubernetes/volume_mount.py	44.44% <0%> (-55.56%)	⬇️
airflow/kubernetes/volume.py	52.94% <0%> (-47.06%)	⬇️
airflow/kubernetes/pod_launcher.py	45.25% <0%> (-46.72%)	⬇️
airflow/kubernetes/refresh_config.py	50.98% <0%> (-23.53%)	⬇️
...rflow/contrib/operators/kubernetes_pod_operator.py	78.75% <0%> (-20%)	⬇️
airflow/models/__init__.py	91.3% <0%> (-8.7%)	⬇️
airflow/utils/cli.py	68.75% <0%> (-5.99%)	⬇️
... and 44 more

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[aviemzur]

R: @ashb

[aviemzur]

@nuclearpinguin added commit changes after CR #1 with the changes you requested

[turbaszek]

There is duplicated check, what about:

job_flow_id = job_flow_id  or emr_hook.get_cluster_id_by_name(self.job_flow_name, self.cluster_states)
if not job_flow_id:
    raise...

[aviemzur]

Sure

[ashb]

Waht do you mean by "fix EmrAddStepsOperator broken ref"? I can't quite decipher this.

Can you please update the PR title to be a line you would like to see in the changelog about this.

[aviemzur]

Waht do you mean by "fix EmrAddStepsOperator broken ref"? I can't quite decipher this.

Can you please update the PR title to be a line you would like to see in the changelog about this.

Sure, how about:
[AIRFLOW-6432] Raise appropriate exception in EmrAddStepsOperator when using job_flow_name and no cluster is found

[turbaszek]

Now I start to think when this exception will be reached? When emr_hook.get_cluster_id_by_name return None. Is it possible or this will fail when calling emr_hook.get_cluster_id_by_name whith self.job_flow_name=None?

[aviemzur]

If you ask for a job_flow_name that doesn't exist it returns None
emr_hook.py
test case