[AIRFLOW-2211] Rename hdfs_sensors.py to hdfs_sensor.py for consistency

[feng-tao]

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-2211

Description

• Here are some details about my PR, including screenshots of any UI changes:
  Rename hdfs_sensors.py to hdfs_sensor.py for consistency.

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:
  no. The change is trivial.

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
  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"

• Passes git diff upstream/master -u -- "*.py" | flake8 --diff

[Fokko]

@feng-tao Can you take a look at the flake8 violations? Cheers

[feng-tao]

thanks @Fokko . Will check today :)

[codecov-io]

Codecov Report

Merging #3127 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3127      +/-   ##
==========================================
- Coverage    73.1%   73.09%   -0.01%     
==========================================
  Files         180      180              
  Lines       12648    12648              
==========================================
- Hits         9246     9245       -1     
- Misses       3402     3403       +1

Impacted Files	Coverage Δ
airflow/models.py	87.28% <0%> (-0.05%)	⬇️

---

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 7a880a7...5def129. Read the comment docs.

[feng-tao]

hey @Fokko , I fix the flake8 error :). Would you mind taking a look?

[Fokko]

@feng-tao Thanks for pinging me. Merging right away. Cheers

[sekikn]

@feng-tao @Fokko This is incompatible change, so should we add an entry to UPDATING.md just like #3141?

[Fokko]

@feng-tao Good point, but this isn't necessary. Splitting the sensors files has been done after 1.8.2 and no release has been done since then, so this will only affect people which are building from master, but I guess they might expect some breaking changes now and then ;)

[sekikn]

@Fokko Sorry if I misunderstand, but airflow/contrib/sensors/hdfs_sensors.py seems to have been shipped with 1.8.0. So I thought this change is backward incompatible since its users from 1.8.0+ have to rewrite import statements in their code. Is this right?

[Fokko]

@sekikn Oops, I missed that. In that case this should be mentioned in the UPDATING.md.

[feng-tao]

@Fokko and @sekikn , let me submit a pr today to add that info in the doc. Thanks for pointing out.

[sekikn]

@feng-tao @Fokko Thanks! :)