Fix generate sequence

[liferoad]

Fixes #35034

./gradlew sdks:java:io:expansion-service:build -x test
python sdks/python/gen_xlang_wrappers.py --cleanup

Test

./gradlew :sdks:java:container:java11:docker

EXPANSION_JARS=sdks/java/io/expansion-service/build/libs/beam-sdks-java-io-expansion-service-2.66.0-SNAPSHOT.jar pytest -v sdks/python/apache_beam/transforms/external_transform_provider_it_test.py::ExternalTransformProviderIT::test_run_generate_sequence_with_rate

Output:

(venv) xqhu@xqhu ~/Dev/beam$ EXPANSION_JARS=sdks/java/io/expansion-service/build/libs/beam-sdks-java-io-expansion-service-2.66.0-SNAPSHOT.jar pytest -v sdks/python/apache_beam/transforms/external_transform_provider_it_test.py::ExternalTransformProviderIT::test_run_generate_sequence_with_rate
========================================================== test session starts ===========================================================
platform linux -- Python 3.9.13, pytest-7.4.4, pluggy-1.5.0 -- /usr/local/google/home/xqhu/Dev/beam/venv/bin/python
cachedir: .pytest_cache
hypothesis profile 'default' -> database=DirectoryBasedExampleDatabase(PosixPath('/usr/local/google/home/xqhu/Dev/beam/.hypothesis/examples'))
rootdir: /usr/local/google/home/xqhu/Dev/beam/sdks/python
configfile: pytest.ini
plugins: requests-mock-1.12.1, xdist-3.6.1, anyio-4.9.0, timeout-2.3.1, hypothesis-6.131.6
timeout: 600.0s
timeout method: signal
timeout func_only: False
collected 1 item                                                                                                                         

sdks/python/apache_beam/transforms/external_transform_provider_it_test.py::ExternalTransformProviderIT::test_run_generate_sequence_with_rate PASSED [100%]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.47%. Comparing base (c507677) to head (916348e).
Report is 35 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #35043      +/-   ##
============================================
- Coverage     56.47%   56.47%   -0.01%     
+ Complexity     3300     3298       -2     
============================================
  Files          1184     1184              
  Lines        181773   181778       +5     
  Branches       3409     3409              
============================================
- Hits         102655   102653       -2     
- Misses        75850    75855       +5     
- Partials       3268     3270       +2     

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[github-actions]

Assigning reviewers:

R: @claudevdm for label python.
R: @kennknowles for label java.

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[ahmedabu98]

This Rate object already has the fields necessary (elements and seconds) to control elements per period. Can you check if this works?

If it doesn't work, I think we can just remove Rate and introduce them as top-level fields

[ahmedabu98]

i.e. something like provider.GenerateSequence(start=0, rate={elements: 3, seconds: 1})

I don't remember if "rate" is provided as a dict or a beam.Row()

[liferoad]

Tested. The dict works well. I also added the test test_run_generate_sequence_with_rate.

[ahmedabu98]

If the current Rate dict works then is there a need for this PR?

I don't think it makes sense to duplicate the API. Maybe we should keep the new rate test though

[liferoad]

The original idea is to create the similar syntax to

beam/sdks/java/core/src/main/java/org/apache/beam/sdk/io/GenerateSequence.java

Line 116 in f9dca88

public GenerateSequence buildExternal(External.ExternalConfiguration config) {

for #35034. If you think we should just keep rate, I am also fine with that.

[liferoad]

#35108