[AIRFLOW-5921] Add bulk_load_custom to MySqlHook

[feluelle]

Make sure you have checked all steps below.

Jira

• My PR addresses the following Airflow Jira issues and references them in the PR title. For example, "[AIRFLOW-XXX] My Airflow PR"
  • https://issues.apache.org/jira/browse/AIRFLOW-5921
  • In case you are fixing a typo in the documentation you can prepend your commit with [AIRFLOW-XXX], code changes always need a Jira issue.
  • In case you are proposing a fundamental code change, you need to create an Airflow Improvement Proposal (AIP).
  • In case you are adding a dependency, check if the license complies with the ASF 3rd Party License Policy.

Description

• Here are some details about my PR, including screenshots of any UI changes:

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:

Commits

• My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Documentation

• In case of new functionality, my PR adds documentation that describes how to use it.
  • All the public functions and the classes in the PR contain docstrings that explain what it does
  • If you implement backwards incompatible changes, please leave a note in the Updating.md so we can assign it to a appropriate release

[codecov-io]

Codecov Report

Merging #6575 into master will decrease coverage by 0.32%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #6575      +/-   ##
==========================================
- Coverage   83.83%   83.51%   -0.33%     
==========================================
  Files         651      651              
  Lines       37431    37437       +6     
==========================================
- Hits        31379    31264     -115     
- Misses       6052     6173     +121

Impacted Files	Coverage Δ
airflow/hooks/mysql_hook.py	93.42% <100%> (+0.56%)	⬆️
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	77.14% <0%> (-21.43%)	⬇️
airflow/configuration.py	89.13% <0%> (-3.63%)	⬇️
airflow/utils/dag_processing.py	58.15% <0%> (-0.33%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update baae140...1805099. Read the comment docs.

[kaxil]

LGTM

[OmerJog]

@feluelle to my understanding bulk load is default to not be supported since MySQL 8 due to security reasons :
https://dev.mysql.com/doc/refman/8.0/en/load-data-local.html

We also have jira about it https://issues.apache.org/jira/browse/AIRFLOW-4051

[feluelle]

@feluelle to my understanding bulk load is default to not be supported since MySQL 8 due to security reasons

That's true it is not enabled by default. But you can enable this by setting local_infile (for mysqlclient) or allow_local_infile (for mysql-connector-python) in your connection.

[feluelle]

Yes, exactly what you wrote in your jira ticket.

[OmerJog]

@feluelle do you think it should be mentioned in the notes of the function?

[feluelle]

I think I wouldn't do it because this can change again and again. It is really special to the mysql client library used. That's why the library is responsible for a good error message and I think it actually logs something useful :)

[feluelle]

But I am not 100 percent sure. If you guys agree I can add something like:

.. warning:: According to the mysql docs using this function is a security risk.
        If you want to use it anyway you can do so by setting a client-side + server-side option.
        This depends on the mysql client library used. See its docs for more information.

WDYT?

[OmerJog]

WDYT?

You are correct.
If local_infile it will raise warning.

if not it will raise error:

ERROR 3950 (42000): Loading local data is disabled; this must be
enabled on both the client and server side

I think this PR also solves https://issues.apache.org/jira/browse/AIRFLOW-4051 but not https://issues.apache.org/jira/browse/AIRFLOW-4050

[feluelle]

This PR does not solve 4051 - it is already solved isn't it?

[feluelle]

@OmerJog PTAL

[OmerJog]

Suggested change

	'table',
	table='table',

What do you think about setting the params explicitly? Makes it more clear I think.

[OmerJog]

LGTM