fix: healthcheck to targets stopped after update upstream

[mrpk1906]

Hi,

As I reported in the issue Kong/kong#7652

When I updated an upstream, healthcheck to targets of this upstream has been stopped.

The bug is by using weak table and ipairs
So, when I updated an upstream, Kong insert a new object contain upstream information to hcs table
When Lua GC removed old object of the upstream => loop with ipairs stopped when got first nil => any upstream object after nil value not will be checked

-- checker objects (weak) table
local hcs = setmetatable({}, {
    __mode = "v",
})

...

for _, checker_obj in ipairs(hcs) do

[CLAassistant]

All committers have signed the CLA.

[kayano]

@Tieske any chance you can take a look, fix seems to be working in my case where we add/delete targets for upstreams and we experience issue with active health checks being disabled.

[gbulanov]

When this PR will be merged ? We are hitting severe production issues due to active healthchecks being disabled when we update the upstream.

Is this fix safe to apply ?

[locao]

Hi @mrpk1906! Thanks for your contribution and sorry for the delay on checking this.

This PR needed to be rebased, I did it in #100 and I'm closing this one.

[ankujuniyal]

Hi @locao, I don't see PR changes requested by @mrpk1906 on release/1.4.2.
it's still.
for _, checker_obj in ipairs(hcs) do

https://github.com/Kong/lua-resty-healthcheck/blob/1.4.2/lib/resty/healthcheck.lua#L1481
Also I am getting same on Kong gateway lua rock lib for health check. Even installation of new kong 2.8.X

[locao]

Hi @ankujuniyal,

The fix submitted by @mrpk1906 was released in lua-resty-healthcheck 1.4.3.

For the 1.5.x series, the fix was released in lua-resty-healthcheck 1.5.1, and Kong uses it since Kong 2.8.1.

If you are using Kong 2.7.2, or any release >= 2.8.1, you should have this fix included. If you have any difficulty installing Kong, please open a discussion in its repo.