in_calyptia_fleet: windows support.

[pwhelan]

Summary

This PR implemenets hot reload in windows for the in_calyptia_fleet plugin. It includes the necessary changes for the plugin itself as well as rudimentary support for hot-reload under win32.

Obstacles

The calyptia fleet plugin reloads configuration taken from calyptia, which requires hot-reload in windows. This requires two major changes:

• fixing TLS under windows: winpthreads: fix off by one bug in pthread_setspecific which impedes setting values monkey/monkey#408.
• Simulating the SIGHUP signal.

Solutions

TLS

The first concern was fixed in monkey and is still awaiting merging upstream to fluent-bit.

SIGHUP

I used GenerateConsoleCtrlEvent to simulate the behavior of the SIGHUP signal in windows and implemented a simple mechanism to signal the main thread from the GenerateConsoleCtrlEvent handler. This is so the main thread can execute flb_reload.

The implementation I went with uses a simple int to mark that the signal has been raised. The main loop then checks it, marks it as zero and then executes flb_reload. This is, admittedly, functional but not elegant.

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Testing
Before we can approve your change; please submit the following in a comment:

• Example configuration file for the change
• Debug log output from testing the change

• Attached Valgrind output that shows no leaks or memory corruption was found

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• Run local packaging test showing all targets (including any new ones) build.
• Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• Documentation required for this feature

Backporting

• Backport to latest stable release.

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[pwhelan]

There is still a blocker concerning the compile error on 32 bit windows which I have yet to resolve.

[patrick-stephens]

There is still a blocker concerning the compile error on 32 bit windows which I have yet to resolve.

This one? https://ci.appveyor.com/project/fluent/fluent-bit-2e87g/builds/48047875/job/ubcx7x6cxx26ftkj
That looks like the usual flaky test...

[ FAILED ]
  log.c:16: Check (*interval >= timeout - 1) && *interval <= timeout... failed
    interval error. got=3 expect=4-5
  log.c:92: Check ret == 0... failed
    update_and_check_interval for TEST_RECORD_01 failed. i=9
  log.c:16: Check (*interval >= timeout - 1) && *interval <= timeout... failed
    interval error. got=3 expect=4-5
  log.c:98: Check ret == 0... failed
    update_and_check_interval for TEST_RECORD_02 failed. i=9
Test cache_one_slot...                          
[ OK ]
FAILED: 1 of 2 unit tests has failed.

[pwhelan]

It was failing on compile before. Seems like my last commit fixed it.

[edsiper]

@pwhelan I merged #7925 which generated some conflicts here, please fix the conflicts.

[pwhelan]

I have resolved the conflicts and added a wrapper for readlink for win32. (I opened the PR #7951 to merge the fix).

The commit 59270d8 from monkey still needs to be integrated before windows reload can work. Without the calyptia fleet plugin will crash during co-routine setup.