lua-nginx-module模块源码浅析

  //master进程初始化时调用
  init_by_lua*

  //worker进程初始化时调用
  init_worker_by_lua* 

  //ssl握手阶段调用
  ssl_certificate_by_lua*

  set_by_lua*

  //rewrite阶段调用
  rewrite_by_lua*

  //access阶段调用, 指令运行于nginx access阶段的末尾，因此总是在allow和deny这样的指令之后运行
  access_by_lua*

  //content阶段调用, 所有请求处理阶段中最为重要的一个，运行在这个阶段的配置指令一般都肩负着生成内容（content）并输出HTTP响应
  content_by_lua*

  //设置upstream阶段调用
  balancer_by_lua*

  //过滤header头, 一般只用于设置Cookie和Headers等
  header_filter_by_lua*

  //过滤body, 一般会在一次请求中被调用多次, 因为这是实现基于HTTP1.1 chunked 编码的所谓“流式输出”的
  body_filter_by_lua*

  //日志阶段
  log_by_lua*

ngx_module_t ngx_http_lua_module = {
    NGX_MODULE_V1,
    &ngx_http_lua_module_ctx,   /*  module context */
    ngx_http_lua_cmds,          /*  module directives */
    NGX_HTTP_MODULE,            /*  module type */
    NULL,                       /*  init master */
    NULL,                       /*  init module */
    ngx_http_lua_init_worker,   /*  init process */
    NULL,                       /*  init thread */
    NULL,                       /*  exit thread */
    NULL,                       /*  exit process */
    NULL,                       /*  exit master */
    NGX_MODULE_V1_PADDING
};

ngx_int_t
ngx_http_lua_init_worker(ngx_cycle_t *cycle)
{
    //获取lua模块的配置信息
    lmcf = ngx_http_cycle_get_module_main_conf(cycle, ngx_http_lua_module);
    ...
    http_ctx
    ...
    //模块create_srv_conf，merge_srv_conf，create_loc_conf，merge_loc_conf
    ...
    ctx = ngx_http_lua_create_ctx(r);
    ...

    //http request放到lua中
    ngx_http_lua_set_req(lmcf->lua, r);

    //init_worker_by的post回调函数
    (void) lmcf->init_worker_handler(cycle->log, lmcf, lmcf->lua);

    ...
}

static ngx_int_t
ngx_http_lua_init(ngx_conf_t *cf)
{
    ...
    lmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_lua_module);
    ...
    //设置ngx http处理阶段的回调函数
    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);

    if (lmcf->requires_rewrite) {
        h = ngx_array_push(&cmcf->phases[NGX_HTTP_REWRITE_PHASE].handlers);
        if (h == NULL) {
            return NGX_ERROR;
        }

        *h = ngx_http_lua_rewrite_handler;
    }

    if (lmcf->requires_access) {
        h = ngx_array_push(&cmcf->phases[NGX_HTTP_ACCESS_PHASE].handlers);
        if (h == NULL) {
            return NGX_ERROR;
        }

        *h = ngx_http_lua_access_handler;
    }

    dd("requires log: %d", (int) lmcf->requires_log);

    if (lmcf->requires_log) {
        arr = &cmcf->phases[NGX_HTTP_LOG_PHASE].handlers;
        h = ngx_array_push(arr);
        if (h == NULL) {
            return NGX_ERROR;
        }

        if (arr->nelts > 1) {
            h = arr->elts;
            ngx_memmove(&h[1], h,
                        (arr->nelts - 1) * sizeof(ngx_http_handler_pt));
        }

        *h = ngx_http_lua_log_handler;
    }

    if (multi_http_blocks || lmcf->requires_header_filter) {
        rc = ngx_http_lua_header_filter_init();
        if (rc != NGX_OK) {
            return rc;
        }
    }

    if (multi_http_blocks || lmcf->requires_body_filter) {
        rc = ngx_http_lua_body_filter_init();
        if (rc != NGX_OK) {
            return rc;
        }
    }

    ...
    //如果lua环境不存在，初始化
    if (lmcf->lua == NULL) {
        lmcf->lua = ngx_http_lua_init_vm(NULL, cf->cycle, cf->pool, lmcf,
                                         cf->log, NULL);
        ...
        //init_by_lua的post回调函数ngx_http_lua_init_by_file
        rc = lmcf->init_handler(cf->log, lmcf, lmcf->lua);
        ...
    }
}

static lua_State *
ngx_http_lua_new_state(lua_State *parent_vm, ngx_cycle_t *cycle,
    ngx_http_lua_main_conf_t *lmcf, ngx_log_t *log)
{
    ...
    L = luaL_newstate();
    ...
    ngx_http_lua_init_registry(L, log);
    ngx_http_lua_init_globals(L, cycle, lmcf, log);

    return L;
}

    { ngx_string("access_by_lua_file"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
                        |NGX_CONF_TAKE1,
      ngx_http_lua_access_by_lua,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      (void *) ngx_http_lua_access_handler_file },

char *
ngx_http_lua_access_by_lua(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    //加载lua文件
    //设置access_handler回调, post函数(ngx_http_lua_access_handler_file)
    llcf->access_handler = (ngx_http_handler_pt) cmd->post;
}

ngx_int_t
ngx_http_lua_access_handler_file(ngx_http_request_t *r)
{
    ...
    //获取lua vm
    L = ngx_http_lua_get_lua_vm(r, NULL);

    //加载lua到cache中
    /*  load Lua script file (w/ cache)        sp = 1 */
    rc = ngx_http_lua_cache_loadfile(r->connection->log, L, script_path,
                                     llcf->access_src_key);
    ...
    return ngx_http_lua_access_by_chunk(L, r);
}

static ngx_int_t
ngx_http_lua_access_by_chunk(lua_State *L, ngx_http_request_t *r)
{
    //开启lua协程,为每个请求分配一个协程
    co = ngx_http_lua_new_thread(r, L, &co_ref);

    ...
    //将request请求与协程绑定
    ngx_http_lua_set_req(co, r);

    ...
    //执行协程
    rc = ngx_http_lua_run_thread(L, r, ctx, 0);

    if (rc == NGX_AGAIN) {
        //协程处理
        rc = ngx_http_lua_run_posted_threads(c, L, r, ctx, nreqs);

        if (rc == NGX_ERROR || rc == NGX_DONE || rc > NGX_OK) {
            return rc;
        }

        if (rc != NGX_OK) {
            return NGX_DECLINED;
        }

    } else if (rc == NGX_DONE) {
        //释放协程
        ngx_http_lua_finalize_request(r, NGX_DONE);

        rc = ngx_http_lua_run_posted_threads(c, L, r, ctx, nreqs);

        if (rc == NGX_ERROR || rc == NGX_DONE || rc > NGX_OK) {
            return rc;
        }

        if (rc != NGX_OK) {
            return NGX_DECLINED;
        }
    }
    ...
}