feature: prometheus plugin apisix_http_status metric route tag Improve recognition

[Donghui0]

Issue description

metric like this:
apisix_http_status{code="200",route="00000000000000000030",service="",node="10.30.30.35"}
The value of the route tag needs to be changed to the real route value instead of route id.
and add host field.
like this:
apisix_http_status{code="200",route="/*", host="www.apisix.com", node="10.30.30.35"}

It is more convenient to query the QPS of the specified route of the domain name

[moonming]

agreed, welcome PR for this

[Donghui0]

When there are multiple values ​​for uris, how does the dispatch method in the lua-resty-radixtree library return which match is successful?
for example:
local rax = radix.new({ { paths = {"/aa/*", "/bb/cc/*", "/dd/ee/index.html"}, metadata = "metadata /aa", } }) rax:match("/bb/cc/xx", opts)
i want to get "/bb/cc/*"

[membphis]

I do not think that is a good way. I think we can add a new field to store the matched uri.

[xxm404]

Modify Prometheus plugin to add a new Uri field? @membphis

[membphis]

it depends on this feature at lua-resty-radixtree: api7/lua-resty-radixtree#41

[swayamraina]

@membphis is this still open for dev?

[tzssangglass]

pls assign this to me, i will solve it on October 20.

[tzssangglass]

Under the condition of setting uris or hosts, I want to record the specific elements in the uris or hosts that match the current request.
At first I tried to take advantage of the pass by reference feature of the table, so I wrote the following code

    handler = function (api_ctx, curr_req_matched_record)
        api_ctx.matched_params = nil
        api_ctx.matched_route = route
        --to keep the record which matches the current request and pass it to api_ctx
        api_ctx.curr_req_matched_record = curr_req_matched_record
    end

    local curr_req_matched_record = {}
    match_opts.matched = curr_req_matched_record

    local ok = uri_router:dispatch(api_ctx.var.uri, match_opts, api_ctx, curr_req_matched_record)

I want to init match_opts.matched , so that I can get the matched record on the callback after dispatch success.

But this can lead to failure in some cases, because of the following code (https://github.com/api7/lua-resty-radixtree/blob/master/lib/resty/radixtree.lua#L456-L458),

    if not opts.matched and not route.param then
        return true
    end

In my case it won't return true.

So this line of thinking tends to be invalid.

I also considered the metadata you mentioned above, but that doesn't solve uris or hosts.

Now I don't have a solution, is there a way to get the specific elements in the uris or hosts that match the current request in apisix?

[membphis]

you can take a look at this, it can help you:

https://github.com/api7/lua-resty-radixtree#synopsis

        -- try to match
        local opts = {
            host = "foo.com",
            method = "GET",
            remote_addr = "127.0.0.1",
            vars = ngx.var,
        }
        ngx.say(rx:match("/aa", opts))

        -- try to match and store the cached value
        local opts = {
            host = "foo.com",
            method = "GET",
            remote_addr = "127.0.0.1",
            vars = ngx.var,
            matched = {}
        }
        ngx.say(rx:match("/name/json/foo/bar/gloo", opts))
        ngx.say("name: ", opts.matched.name, " other:", opts.matched.other)

[membphis]

here are more cases: https://github.com/api7/lua-resty-radixtree/search?q=matched

[tzssangglass]

I saw the example above, init match_opts.matched is probably the right way to think about it, as https://github.com/api7/lua-resty-radixtree#synopsis, I did.

    match_opts.method = api_ctx.var.request_method
    match_opts.host = api_ctx.var.host
    match_opts.remote_addr = api_ctx.var.remote_addr
    match_opts.vars = api_ctx.var

    match_opts.matched = {}
    local ok = uri_router:dispatch(api_ctx.var.uri, match_opts, api_ctx)

But in this test case

apisix/t/node/sanity-radixtree.t

Lines 127 to 133 in 71dcf36

	=== TEST 6: hit routes: /hello1
	--- request
	GET /hello1
	--- response_body
	hello1 world
	--- no_error_log
	[error]

It will cause the test to fail. The reason is the following code:

        if match_route_opts(route, opts, args) then
            -- log_info("matched route: ", require("cjson").encode(route))
            -- log_info("matched path: ", path)
            if compare_param(path, route, opts) then
                if opts_matched_exists then
                    opts.matched._path = route.path_org
                end
                return route
            end
        end

https://github.com/api7/lua-resty-radixtree/blob/6b5d65eb9853c91b1d23cc4cea8941be74bb5f20/lib/resty/radixtree.lua#L663-L666

case 1: did't init match_opts.matched

The test case will success, because not opts.matched and not route.param = true .

The logic goes as follows

case 2: init match_opts.matched

The test case will fail, because not opts.matched and not route.param = false, then execute the following code in the function compare_param .

The logic goes as follows

So in this test case, init matched will cause a 404, is this to use matched and metedate in combination? But I understand that matched should always work, and metedate is used to tag the url pass of the restful api.

[tzssangglass]

In radixtree# _match_from_routes function, may be judgement if it's a prefix matching before calling the compare_param function, and if so, simply return.

like this

        if match_route_opts(route, opts, ...) then
            -- log_info("matched route: ", require("cjson").encode(route))
            -- log_info("matched path: ", path)

            --judgement if it's a prefix matching
            local last_char = string.sub(route.path_org, #route.path_org)
            ngx.log(ngx.WARN, "last_char: ", last_char)
            if last_char and last_char == '*' then
                if opts_matched_exists then
                    opts.matched._path = route.path_org
                end
                return route
            end

            if compare_param(path, route, opts) then
                if opts_matched_exists then
                    opts.matched._path = route.path_org
                end
                return route
            end
        end

        ::continue::

[membphis]

@tzssangglass welcome PR to fix this bug.

if we need to https://github.com/api7/lua-resty-radixtree , welcome to create a new issue first at radixtree.

[tzssangglass]

@tzssangglass welcome PR to fix this bug.

if we need to https://github.com/api7/lua-resty-radixtree , welcome to create a new issue first at radixtree.

ok, i try