refactor: multiprocessing helper

[NguyenHoangSon96]

Closes #

Proposed Changes

• Refactor MultiprocessingWriter class:
  - WriteApi will be created and used directly in the class for writing.
  - Tests are added for writing with multiprocessing.
  - Use DefaultContext.Process(target) to create a new process.
  - Users can now choose one of the start methods fork, spawn or forkserver when creating a new Process. The default will be spawn.
  - Implement a time-to live mechanism for child processes. I just set timeout for JoinableQueue.get() so It will wait for a number of times, default is 300 seconds, and users can pass in their own value to override that by process_ttl parameter.
  - Users can pass in an on_shutdown() function which gets called when the queue has been shutdown.

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• A test has been added if appropriate
• Tests pass
• Commit messages are conventional
• Sign CLA (if not already signed)

[codecov]

Codecov Report

❌ Patch coverage is 97.67442% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 86.88%. Comparing base (b24d6c1) to head (011c1b6).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...write_client/client/util/multiprocessing_helper.py	97.67%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #222      +/-   ##
==========================================
- Coverage   87.21%   86.88%   -0.33%     
==========================================
  Files          28       28              
  Lines        2072     2082      +10     
==========================================
+ Hits         1807     1809       +2     
- Misses        265      273       +8     

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[Copilot]

Pull request overview

This PR refactors the write stack by removing the generated OpenAPI-style service/client layer and moving write request construction and HTTP dispatch directly into WriteApi, while also updating tests and documentation to reflect the new behavior and configuration surface.

Changes:

• Refactors WriteApi to perform request preparation + HTTP calls directly via a new low-level RestClient (removing ApiClient/WriteService/Configuration).
• Updates InfluxDBClient3 initialization and tests to use the new header/rest client approach and to validate required constructor keys.
• Refactors and adds integration coverage for MultiprocessingWriter start-method behavior and direct WriteApi usage.

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
CHANGELOG.md	Documents breaking changes and new construction patterns (example needs a small syntax fix).
influxdb_client_3/init.py	Reworks InfluxDBClient3 construction to create RestClient + WriteApi directly and enforce required keys.
influxdb_client_3/write_client/init.py	Removes deprecated exports and re-exports updated WriteApi/types.
influxdb_client_3/write_client/_sync/api_client.py	Removes legacy generated ApiClient.
influxdb_client_3/write_client/_sync/rest.py	Removes legacy generated REST client implementation.
influxdb_client_3/write_client/_sync/rest_client.py	Adds new RestClient for low-level HTTP handling + logging/redaction.
influxdb_client_3/write_client/client/init.py	Removes re-export of removed WriteService.
influxdb_client_3/write_client/client/_base.py	Removes legacy base client/write-api helpers tied to generated stack.
influxdb_client_3/write_client/client/influxdb_client.py	Removes legacy v2 InfluxDBClient.
influxdb_client_3/write_client/client/logging_handler.py	Removes InfluxLoggingHandler implementation.
influxdb_client_3/write_client/client/util/helpers.py	Updates exception import path.
influxdb_client_3/write_client/client/util/multiprocessing_helper.py	Refactors MultiprocessingWriter to create WriteApi directly and set default start method.
influxdb_client_3/write_client/client/write/init.py	Removes legacy re-export of removed WriteService.
influxdb_client_3/write_client/client/write_api.py	Major refactor: WriteApi becomes standalone, builds write requests and calls RestClient directly, retains batching pipeline.
influxdb_client_3/write_client/configuration.py	Removes legacy generated configuration object.
influxdb_client_3/write_client/service/init.py	Removes legacy service package init exporting WriteService.
influxdb_client_3/write_client/service/_base_service.py	Removes legacy service base class.
influxdb_client_3/write_client/service/write_service.py	Removes legacy generated WriteService.
influxdb_client_3/write_client/write_exceptions.py	Removes _BaseRESTClient logger helper (moved to RestClient).
tests/test_influxdb_client_3.py	Updates unit tests for new client/write header/rest behavior and required params.
tests/test_influxdb_client_3_integration.py	Adds integration tests for direct WriteApi usage, multiprocessing helper, and async call path.
tests/test_polars.py	Updates write tests to mock WriteApi call sites instead of WriteService.
tests/test_query.py	Fixes typo in client init parameter (database).
tests/test_write_api.py	Refactors tests from generated service/client usage to InfluxDBClient3/WriteApi usage.
tests/test_write_local_server.py	Updates exception import path.

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[Copilot]

Pull request overview

Copilot reviewed 25 out of 25 changed files in this pull request and generated 3 comments.

[NguyenHoangSon96]

@bednar @karel-rehor @alespour
Hi guys,
I made some quite big changes to our MultiprocessingWriter class.
Please take a look. I'm not very familiar with multiprocessing in Python.

[karel-rehor]

This looks good so far.

I especially like the use of get_context() for each instance. It's cleaner, more flexible and more stable than what I suggested last week.

A couple of notes.

1. need to update CHANGELOG.md

2. The codecov report shows that important parts of the run and terminate methods are not covered by tests.

I think this is partially a false report. I suspect codecov is not tracking code executed in newly spawned processes. When running tests in the debugger, I see the processes enter this area of code. It's probably necessary to configure codecov to follow multiprocess executions.

e.g. in pyproject.toml (+AI+ suggestion 1)

[tool.coverage.run]
concurrency = ["multiprocessing"]
parallel = true
source = ["your_package_name"]

or perhaps in .coveragerc (+AI+ suggestion 2)

[run]
concurrency = multiprocessing
parallel = true
source = your_package_name

It was suggested in a PR for influxdb-client-php that CircleCI has a codecov orb that simplifies working with codecoverage reports. It might help resolve this issue.

[NguyenHoangSon96]

Hi @karel-rehor

CHANGES:

• Move WriteApi initiation steps outside of the child process so it can fail fast inside the parent process if there are any issues.
• Implement a time-to live mechanism for child processes. I just set timeout for JoinableQueue.get() so It will wait for a number of times, default is 300 seconds, and users can pass in their own value to override that by process_ttl param.
• Users can pass in an on_shutdown() function which gets called when the queue has been shutdown.
• Users don't have to manually provide RestClient anymore.
• Tests added for those changes.

TODO:

• Update CHANGELOG.md and this PR description section.

Please click "Resolve conversation" after all issues have been fixed.

[karel-rehor]

I still have a couple of minor requests, regarding tests and CHANGELOG.md.

[karel-rehor]

Thanks for the last minute changes.

Looks good to me. 🚴 🏁