lua-resty-dns-client

• Index

Contents

• Functions

Modules

• resty.dns.balancer.base
• resty.dns.balancer.consistent_hashing
• resty.dns.balancer.handle
• resty.dns.balancer.least_connections
• resty.dns.balancer.round_robin
• resty.dns.client
• resty.dns.utils

Topics

• README

Module resty.dns.balancer.handle

Handle module.

Implements handles to be used by the objBalancer:getPeer method. These implement a __gc method for tracking statistics and not leaking resources in case a connection gets aborted prematurely.

This module is only relevant when implementing your own balancer algorithms.

Info:

• Copyright: 2016-2020 Kong Inc. All rights reserved.
• License: Apache 2.0
• Author: Thijs Schreijer

Functions

get (__gc)	Gets a handle from the cache.
release (handle)	Returns a handle to the cache.
setCacheSize (size)	Sets a new cache size.

Functions

get (__gc)

Gets a handle from the cache. The handle comes from the cache or it is newly created. A handle is just a table. It will have two special fields:

• __udata: (read-only) a userdata used to track the lifetime of the handle
• __gc: (read/write) this method will be called on GC.

NOTE: the __gc will only be called when the handle is garbage collected, not when it is returned by calling release.

Parameters:

• __gc (optional, function) the method called when the handle is GC'ed.

Returns:

handle

Usage:

local handle = _M

local my_gc_handler = function(self)
  print(self.name .. " was deleted")
end

local h1 = handle.get(my_gc_handler)
h1.name = "Obama"
local h2 = handle.get(my_gc_handler)
h2.name = "Trump"

handle.release(h1)   -- explicitly release it
h1 = nil
h2 = nil             -- not released, will be GC'ed
collectgarbage()
collectgarbage()     --> "Trump was deleted"

release (handle)

Returns a handle to the cache. The handle will be cleared, returned to the cache, and its __gc handle will NOT be called.

Parameters:

• handle the handle to return to the cache

Returns:

nothing

setCacheSize (size)

Sets a new cache size. The default size is 1000.

Parameters:

• size the new size.

Returns:

nothing, or throws an error on bad input