test_child_process: ensure to shutdown plugin instances (#5331)

Which issue(s) this PR fixes: Fixes #

What this PR does / why we need it: Fix thread and resource leaks in test_output.rb by ensuring proper shutdown sequences for plugin instances.

Before:

$ ruby -Ilib:test -e "at_exit { puts '--- Thread count at exit: ' + Thread.list.size.to_s;  pp Thread.list }; require './test/plugin_helper/test_child_process.rb'"
Loaded suite -e
Started
P
===========================================================================================================================================
Pending: test: can scrub characters without exceptions(ChildProcessTest): Behaviour of IO#set_encoding is changed as of Ruby 3.3 (#4058)
/home/watson/src/fluentd/test/plugin_helper/test_child_process.rb:519:in 'block in <class:ChildProcessTest>'
===========================================================================================================================================
P
===========================================================================================================================================
Pending: test: can scrub characters without exceptions and replace specified chars(ChildProcessTest): Behaviour of IO#set_encoding is changed as of Ruby 3.3 (#4058)
/home/watson/src/fluentd/test/plugin_helper/test_child_process.rb:545:in 'block in <class:ChildProcessTest>'
===========================================================================================================================================
Finished in 34.07304912 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------
33 tests, 96 assertions, 0 failures, 0 errors, 2 pendings, 0 omissions, 0 notifications
93.9394% passed
-------------------------------------------------------------------------------------------------------------------------------------------
0.97 tests/s, 2.82 assertions/s
--- Thread count at exit: 3
[#<Thread:0x00007f49708b7f48 run>,
 #<Thread:0x00007f4954bb2908@event_loop /home/watson/src/fluentd/lib/fluent/plugin_helper/thread.rb:70 sleep>,
 #<Thread:0x00007f4954ba6310@Timeout stdlib thread /home/watson/.rbenv/versions/4.0.2/lib/ruby/4.0.0/timeout.rb:87 sleep>]

After:

$ ruby -Ilib:test -e "at_exit { puts '--- Thread count at exit: ' + Thread.list.size.to_s;  pp Thread.list }; require './test/plugin_helper/test_child_process.rb'"
Loaded suite -e
Started
P
===========================================================================================================================================
Pending: test: can scrub characters without exceptions(ChildProcessTest): Behaviour of IO#set_encoding is changed as of Ruby 3.3 (#4058)
/home/watson/src/fluentd/test/plugin_helper/test_child_process.rb:524:in 'block in <class:ChildProcessTest>'
===========================================================================================================================================
P
===========================================================================================================================================
Pending: test: can scrub characters without exceptions and replace specified chars(ChildProcessTest): Behaviour of IO#set_encoding is changed as of Ruby 3.3 (#4058)
/home/watson/src/fluentd/test/plugin_helper/test_child_process.rb:550:in 'block in <class:ChildProcessTest>'
===========================================================================================================================================
Finished in 34.153673569 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------
33 tests, 96 assertions, 0 failures, 0 errors, 2 pendings, 0 omissions, 0 notifications
93.9394% passed
-------------------------------------------------------------------------------------------------------------------------------------------
0.97 tests/s, 2.81 assertions/s
--- Thread count at exit: 2
[#<Thread:0x00007fb335e77fa8 run>,
#<Thread:0x00007fb319d758b0@Timeout stdlib thread /home/watson/.rbenv/versions/4.0.2/lib/ruby/4.0.0/timeout.rb:87 sleep>]

Docs Changes:

Release Note:

Signed-off-by: Shizuo Fujita fujita@clear-code.com

Fluentd: Open-Source Log Collector

Fluentd collects events from various data sources and writes them to files, RDBMS, NoSQL, IaaS, SaaS, Hadoop and so on. Fluentd helps you unify your logging infrastructure (Learn more about the Unified Logging Layer).

Quick Start

$ gem install fluentd
$ fluentd -s conf
$ fluentd -c conf/fluent.conf &
$ echo '{"json":"message"}' | fluent-cat debug.test

Development

Branch

master: For v1 development.
v0.12: For v0.12. This is deprecated version. we already stopped supporting (See https://www.fluentd.org/blog/drop-schedule-announcement-in-2019).

Prerequisites

Ruby 3.2 or later
git

git should be in PATH. On Windows, you can use Github for Windows and GitShell for easy setup.

Install dependent gems

Use bundler:

$ gem install bundler
$ bundle install --path vendor/bundle

Run test

$ bundle exec rake test

You can run specified test via TEST environment variable:

$ bundle exec rake test TEST=test/test_specified_path.rb
$ bundle exec rake test TEST=test/test_*.rb

More Information

Website: https://www.fluentd.org/
Documentation: https://docs.fluentd.org/
Project repository: https://github.com/fluent
Discussion: https://github.com/fluent/fluentd/discussions
Slack / Community: https://slack.fluentd.org
Newsletters: https://www.fluentd.org/newsletter
Author: Sadayuki Furuhashi
License: Apache License, Version 2.0

Security

A third party security audit was performed by Cure53, you can see the full report here.

See SECURITY to contact us about vulnerability.

Contributors:

Patches contributed by great developers.