OpenResty中使用lua-resty-radixtree遇API禁用错误求助

错误信息 #

ERROR: /usr/local/openresty/luajit/share/lua/5.1/resty/expr/v1.lua:319: API disabled in the current context
stack traceback:
        /usr/local/openresty/lualib/resty/core/var.lua:103: in function '__index'
        /usr/local/openresty/luajit/share/lua/5.1/resty/expr/v1.lua:319: in function 'eval'
        ...local/openresty/luajit/share/lua/5.1/resty/radixtree.lua:579: in function 'match_route_opts'
        ...local/openresty/luajit/share/lua/5.1/resty/radixtree.lua:642: in function 'match_route'
        ...local/openresty/luajit/share/lua/5.1/resty/radixtree.lua:675: in function 'match'
        lua/hello.lua:30: in function 'file_gen'
        init_worker_by_lua:45: in function <init_worker_by_lua:43>
        [C]: in function 'xpcall'
        init_worker_by_lua:52: in function <init_worker_by_lua:50>

相关配置文件 #

nginx.conf #

pid logs/nginx.pid;
worker_processes  1;
events {
  worker_connections 1024;
}

http {
  server {
    listen 8080;
    location / {
      content_by_lua_file lua/hello.lua;
      }
    }
  }

hello.lua #

ngx.say("Hello user!")

local radix = require("resty.radixtree")
local rx = radix.new({
    {
        paths = { "/aa", "/bb*", "/name/:name/*other" },
        hosts = { "*.bar.com", "foo.com" },
        methods = { "GET", "POST", "PUT" },
        remote_addrs = { "127.0.0.1", "192.168.0.0/16",
            "::1", "fe80::/32" },
        vars = {
            { "arg_name",   "==", "json" },
            { "arg_weight", ">",  10 },
        },
        filter_fun = function(vars, opts)
            return vars["arg_name"] == "json"
        end,

        metadata = "metadata /bb",
    }
})

-- 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)

问题原因 #

1. 错误栈显示代码实际在init_worker_by_lua阶段执行，但该阶段属于非请求上下文，无法访问ngx.var这类请求相关API。
2. ngx.var是请求级别的变量，仅能在请求处理阶段（如content_by_lua、access_by_lua等）使用，init_worker阶段是worker进程启动时的初始化逻辑，没有请求上下文，调用ngx.var会触发该错误。
3. 你提供的nginx.conf配置是用content_by_lua_file执行hello.lua，但错误栈显示实际运行时代码被init_worker_by_lua调用，存在配置不一致的情况。

解决方法 #

• 确保hello.lua仅在请求处理阶段执行：保持nginx.conf中content_by_lua_file lua/hello.lua的配置，检查是否有其他地方（如init_worker_by_lua）误引用了该文件。
• 拆分代码逻辑：如果需要提前初始化radixtree，可以将radix.new()放在init_by_lua或init_worker_by_lua中，但rx:match()方法必须放在请求处理阶段执行，不能在init_worker阶段调用。
• 核对实际运行的Nginx配置，确认没有错误地将hello.lua挂载到init_worker_by_lua指令下。

内容的提问来源于stack exchange，提问作者Navendu Pottekkat