OpenResty XRay YLua Analyzer

# About YLua Analyzer

The YLua parser allows you to write a Lua analyzer using the Lua syntax. Sometimes we want to be able to identify what data is in a Lua table and what the values of the data are. This is where the YLua parser can come in handy.

# YLua Analyzer Example

The following example outputs the regular expressions cached in resty.core.regex.

probe process.begin
    local max_output_cnt = 1000
    local regex = package.loaded["resty.core.regex"]
    local regex_match_cache = upval(regex.re_match_compile, "regex_match_cache")

    if regex_match_cache ~= nil then
        local match_regex_cache_count = 0
        for key, _ in pairs(regex_match_cache.key2node) do
            if match_regex_cache_count < max_output_cnt then
                print("match-pattern: ", key)
            end
            match_regex_cache_count = match_regex_cache_count + 1
        end

        print("match_regex_cache_count: ", match_regex_cache_count)
    end

    exit()
end

After executing the tool, we will get the following output:

To the right of the YSQL tab is the Learn YLua shortcut link to the YLua user manual. Users can click on the link for a description of YLua syntax and features.