[tarantool-patches] Re: [PATCH][vshard] Reload reloadable fiber
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Wed Jun 27 12:54:19 MSK 2018
Hello. Thanks for the fixes! See 4 comments below.
On 26/06/2018 15:50, Alex Khatskevich wrote:
> Sorry, I forgot to put the new patch here
>
> commit 4ddab3c47c5963c3138701d89ba3091d5da9848a
> Author: AKhatskevich <avkhatskevich at tarantool.org>
> Date: Thu Jun 14 14:03:07 2018 +0300
>
> Reload reloadable fiber
>
> Fixed a problem:
> The `reloadable_fiber_f` was running an infinite while loop and
> preventing the whole module from being reloaded.
>
> This behavior is fixed by calling new version of `reloadable_fiber_f` in
> a return statement instead of the where loop. Note: calling a function
1. Again 'where loop'.
> in a return statement doesn't increase a stack size.
>
> Extra changes:
> * transfer write "started" message responsibility from caller to
> reloadable fiber
>
> Closes #116
>
> diff --git a/test/unit/util.result b/test/unit/util.result
> new file mode 100644
> index 0000000..dbfcce9
> --- /dev/null
> +++ b/test/unit/util.result
> @@ -0,0 +1,72 @@
> +test_run = require('test_run').new()
> +---
> +...
> +fiber = require('fiber')
> +---
> +...
> +log = require('log')
> +---
> +...
> +test_util = require('util')
> +---
> +...
> +util = require('vshard.util')
> +---
> +...
> +test_run:cmd("setopt delimiter ';'")
> +---
> +- true
> +...
> +fake_M = {
> + reloadable_func = nil,
> + module_version = 1,
> +};
> +---
> +...
> +test_run:cmd("setopt delimiter ''");
> +---
> +- true
> +...
> +-- Check autoreload on function change during failure.
> +fake_M.reloadable_function = function () fake_M.reloadable_function = 42; error('Error happened.') end
> +---
> +...
> +fib = fiber.create(util.reloadable_fiber_f, fake_M, 'reloadable_function', 'Worker_name')
> +---
> +...
> +fib:cancel()
> +---
> +...
> +test_run:grep_log('default', 'Worker_name: reloadable function reloadable_function has changed')
2. 'Has been' changed?
> +---
> +- 'Worker_name: reloadable function reloadable_function has changed'
> +...
> diff --git a/vshard/util.lua b/vshard/util.lua
> index bb71318..920f53e 100644
> --- a/vshard/util.lua
> +++ b/vshard/util.lua
> @@ -19,33 +32,37 @@ local function tuple_extract_key(tuple, parts)
> +local function reloadable_fiber_f(module, func_name, worker_name)
> + log.info('%s has been started', worker_name)
> + local func = module[func_name]
> + local ok, err = pcall(func, module.module_version)
> + if not ok then
> + log.error('%s has been failed: %s', worker_name, err)
> + if func ~= module[func_name] then
> + log.warn('%s: reloadable function %s has changed',
> + worker_name, func_name)
3. Why is these check and warn here, after an error?
> end
> end
> + -- yield serves two pursoses:
> + -- * makes this fiber cancellable
> + -- * prevents 100% cpu consumption
> + fiber.yield()
> + log.info('%s is reloaded, restarting', worker_name)
4. Why do you print 'is reloaded' even if it just thrown an error
and the function is not changed actually?
> + -- luajit drops this frame if next function is called in
> + -- return statement.
> + return M.reloadable_fiber_f(module, func_name, worker_name)
> end
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