Re: [DISCUSS] chash key support more flexible ways

[李凌]

I do think we can learn this part from OpenResty Edge,
also I like the idea that take a Chash key from Header ,which is pretty
meaningful for us.

[image: image.png]


Ming Wen <wenm...@apache.org> 于2019年12月23日周一 下午9:04写道：

> yuansheng, what do you think?
>
> Thanks,
> Ming Wen, Apache APISIX
> Twitter: _WenMing
>
>
> Ming Wen <wenm...@apache.org> 于2019年12月23日周一 下午9:03写道：
>
> > hi, codjust,
> > I prefer your design than the existing one[1].
> >
> > These categories "vars", "header", "cookie", "consumer" are friendly for
> > developer.
> >
> > [1]
> >
> https://github.com/apache/incubator-apisix/blob/master/lua/apisix/schema_def.lua#L261
> >
> > Thanks,
> > Ming Wen, Apache APISIX
> > Twitter: _WenMing
> >
> >
> > codjust <hcw1...@foxmail.com> 于2019年12月23日周一 下午8:58写道：
> >
> >> Now chash key only support fetch from nginx variable. We need to be more
> >> flexible approach，
> >> eg: cookie, custom header and so on.
> >> Here is an example to achieve:
> >> upstream json schema：
> >> hash_on = {
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; type = "string",
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; default = "vars",
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; enum = {
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "vars",
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "header",
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "cookie",
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "consumer"
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; },
> >> &nbsp; &nbsp; &nbsp; &nbsp; },
> >> &nbsp; &nbsp; &nbsp; &nbsp; key = {
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; description = "the key of
> chash
> >> for dynamic load balancing",
> >> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; type = "string"
> >> &nbsp; &nbsp; &nbsp; &nbsp; },
> >>
> >>
> >> eg:
> >> local function create_chash_hash_key(ctx, upstream)
> >> &nbsp; &nbsp; local key = upstream.key&nbsp;
> >> &nbsp; &nbsp; local hash_on = upstream.hash_on
> >> &nbsp; &nbsp; local chash_key
> >> &nbsp; &nbsp; -- from nginx variable
> >> &nbsp; &nbsp; if hash_on == "vars" then&nbsp;
> >> &nbsp; &nbsp; &nbsp; &nbsp; chash_key = ctx.var[key]
> >> &nbsp; &nbsp; elseif hash_on == "header" then&nbsp;
> >> &nbsp; &nbsp; &nbsp; &nbsp; chash_key = ngx.req.get_headers()[key]
> >> &nbsp; &nbsp; elseif hash_on == "cookie" then&nbsp;
> >> &nbsp; &nbsp; &nbsp; &nbsp; chash_key = ctx.var["cookie_" .. key]
> >> &nbsp; &nbsp; &nbsp; &nbsp; -- TODO chash_key doesn't exist, set-cookie
> >> &nbsp; &nbsp; end
> >> &nbsp; &nbsp; if not chash_key then&nbsp;
> >> &nbsp; &nbsp; &nbsp; &nbsp; chash_key = ctx.var["remote_addr"]
> >> &nbsp; &nbsp; end
> >> &nbsp; &nbsp; return chash_key
> >> end
> >>
> >>
> >> hash_on type desc:
> >> 1 vars: fetchs nginx variable
> >> 2 header: custom headers or standard http headers
> >> 3 cookie: fetch chash key from cookie. It can be used to sticky session
> >> 4 consumer: hash by consumer_id
> >> If the specified chash key is not present, use default key:
> >> remote_addr(it can also provide default settings).
> >>
> >>
> >> everybody have a better idea?
> >>
> >> github issue:
> >> https://github.com/apache/incubator-apisix/issues/992
> >
> >
>