nginx的upstream模块

编程技术  /  houtizong 发布于 3年前   118

参考http://nginx.weebly.com/31034203632830430721.html第五章
http://tengine.taobao.org/book/chapter_05.html
config文件

[root@VM_12_197_centos upstream]# cat config ngx_addon_name=ngx_http_mytest_moduleHTTP_MODULES="$HTTP_MODULES ngx_http_mytest_module"NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_mytest_module.c"[root@VM_12_197_centos upstream]# 

配置文件

[root@VM_12_197_centos upstream]# cat nginx.conf#user  nobody;worker_processes  1;error_log  logs/error.log  debug;events {    worker_connections  1024;}http {    include       mime.types;    default_type  application/octet-stream;    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '    #                  '$status $body_bytes_sent "$http_referer" '    #                  '"$http_user_agent" "$http_x_forwarded_for"';    #access_log  logs/access.log  main;    keepalive_timeout  65;    server {        listen 8080;        location /test {                mytest;        }    }}[root@VM_12_197_centos upstream]# 

模块代码

#include <ngx_config.h>#include <ngx_core.h>#include <ngx_http.h>typedef struct{    ngx_http_status_t           status;    ngx_str_t                                   backendServer;} ngx_http_mytest_ctx_t;typedef struct{    ngx_http_upstream_conf_t upstream;} ngx_http_mytest_conf_t;static char *ngx_http_mytest(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);static ngx_int_t ngx_http_mytest_handler(ngx_http_request_t *r);static void* ngx_http_mytest_create_loc_conf(ngx_conf_t *cf);static char *ngx_http_mytest_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child);static ngx_int_tmytest_upstream_process_header(ngx_http_request_t *r);static ngx_int_tmytest_process_status_line(ngx_http_request_t *r);static ngx_str_t  ngx_http_proxy_hide_headers[] ={    ngx_string("Date"),    ngx_string("Server"),    ngx_string("X-Pad"),    ngx_string("X-Accel-Expires"),    ngx_string("X-Accel-Redirect"),    ngx_string("X-Accel-Limit-Rate"),    ngx_string("X-Accel-Buffering"),    ngx_string("X-Accel-Charset"),    ngx_null_string};static ngx_command_t  ngx_http_mytest_commands[] ={    {        ngx_string("mytest"),        NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_HTTP_LMT_CONF | NGX_CONF_NOARGS,        ngx_http_mytest,        NGX_HTTP_LOC_CONF_OFFSET,        0,        NULL    },    ngx_null_command};static ngx_http_module_t  ngx_http_mytest_module_ctx ={    NULL,                              /* preconfiguration */    NULL,                               /* postconfiguration */    NULL,                              /* create main configuration */    NULL,                              /* init main configuration */    NULL,                              /* create server configuration */    NULL,                              /* merge server configuration */    ngx_http_mytest_create_loc_conf,                            /* create location configuration */    ngx_http_mytest_merge_loc_conf                              /* merge location configuration */};ngx_module_t  ngx_http_mytest_module ={    NGX_MODULE_V1,    &ngx_http_mytest_module_ctx,           /* module context */    ngx_http_mytest_commands,              /* module directives */    NGX_HTTP_MODULE,                       /* module type */    NULL,                                  /* init master */    NULL,                                  /* init module */    NULL,                                  /* init process */    NULL,                                  /* init thread */    NULL,                                  /* exit thread */    NULL,                                  /* exit process */    NULL,                                  /* exit master */    NGX_MODULE_V1_PADDING};static void* ngx_http_mytest_create_loc_conf(ngx_conf_t *cf){    ngx_http_mytest_conf_t  *mycf;    mycf = (ngx_http_mytest_conf_t  *)ngx_pcalloc(cf->pool, sizeof(ngx_http_mytest_conf_t));    if (mycf == NULL)    {        return NULL;    }    //以下简单的硬编码ngx_http_upstream_conf_t结构中的各成员，例如//超时时间都设为1分钟。这也是http反向代理模块的默认值    mycf->upstream.connect_timeout = 60000;    mycf->upstream.send_timeout = 60000;    mycf->upstream.read_timeout = 60000;    mycf->upstream.store_access = 0600;    //实际上buffering已经决定了将以固定大小的内存作为缓冲区来转发上游的//响应包体，这块固定缓冲区的大小就是buffer_size。如果buffering为1//就会使用更多的内存缓存来不及发往下游的响应，例如最多使用bufs.num个//缓冲区、每个缓冲区大小为bufs.size，另外还会使用临时文件，临时文件的//最大长度为max_temp_file_size    mycf->upstream.buffering = 0;    mycf->upstream.bufs.num = 8;    mycf->upstream.bufs.size = ngx_pagesize;    mycf->upstream.buffer_size = ngx_pagesize;    mycf->upstream.busy_buffers_size = 2 * ngx_pagesize;    mycf->upstream.temp_file_write_size = 2 * ngx_pagesize;    mycf->upstream.max_temp_file_size = 1024 * 1024 * 1024;    //upstream模块要求hide_headers成员必须要初始化（upstream在解析//完上游服务器返回的包头时，会调用//ngx_http_upstream_process_headers方法按照hide_headers成员将//本应转发给下游的一些http头部隐藏），这里将它赋为//NGX_CONF_UNSET_PTR ，是为了在merge合并配置项方法中使用//upstream模块提供的ngx_http_upstream_hide_headers_hash//方法初始化hide_headers 成员    mycf->upstream.hide_headers = NGX_CONF_UNSET_PTR;    mycf->upstream.pass_headers = NGX_CONF_UNSET_PTR;    return mycf;}static char *ngx_http_mytest_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child){    ngx_http_mytest_conf_t *prev = (ngx_http_mytest_conf_t *)parent;    ngx_http_mytest_conf_t *conf = (ngx_http_mytest_conf_t *)child;    ngx_hash_init_t             hash;    hash.max_size = 100;    hash.bucket_size = 1024;    hash.name = "proxy_headers_hash";    if (ngx_http_upstream_hide_headers_hash(cf, &conf->upstream,                                            &prev->upstream, ngx_http_proxy_hide_headers, &hash)        != NGX_OK)    {        return NGX_CONF_ERROR;    }    return NGX_CONF_OK;}static ngx_int_tmytest_upstream_create_request(ngx_http_request_t *r){    //发往google上游服务器的请求很简单，就是模仿正常的搜索请求，//以/search?q=…的URL来发起搜索请求。backendQueryLine中的%V等转化//格式的用法，请参见4.4节中的表4-7    static ngx_str_t backendQueryLine =        ngx_string("GET /search?q=%V HTTP/1.1\r\nHost: www.google.com\r\nConnection: close\r\n\r\n");    ngx_int_t queryLineLen = backendQueryLine.len + r->args.len - 2;    //必须由内存池中申请内存，这有两点好处：在网络情况不佳的情况下，向上游//服务器发送请求时，可能需要epoll多次调度send发送才能完成，//这时必须保证这段内存不会被释放；请求结束时，这段内存会被自动释放，//降低内存泄漏的可能    ngx_buf_t* b = ngx_create_temp_buf(r->pool, queryLineLen);    if (b == NULL)        return NGX_ERROR;    //last要指向请求的末尾    b->last = b->pos + queryLineLen;    //作用相当于snprintf，只是它支持4.4节中的表4-7列出的所有转换格式    ngx_snprintf(b->pos, queryLineLen ,                 (char*)backendQueryLine.data, &r->args);    // r->upstream->request_bufs是一个ngx_chain_t结构，它包含着要//发送给上游服务器的请求    r->upstream->request_bufs = ngx_alloc_chain_link(r->pool);    if (r->upstream->request_bufs == NULL)        return NGX_ERROR;    // request_bufs这里只包含1个ngx_buf_t缓冲区    r->upstream->request_bufs->buf = b;    r->upstream->request_bufs->next = NULL;    r->upstream->request_sent = 0;    r->upstream->header_sent = 0;    // header_hash不可以为0    r->header_hash = 1;    return NGX_OK;}static ngx_int_tmytest_process_status_line(ngx_http_request_t *r){    size_t                 len;    ngx_int_t              rc;    ngx_http_upstream_t   *u;    //上下文中才会保存多次解析http响应行的状态，首先取出请求的上下文    ngx_http_mytest_ctx_t* ctx = ngx_http_get_module_ctx(r, ngx_http_mytest_module);    if (ctx == NULL)    {        return NGX_ERROR;    }    u = r->upstream;    //http框架提供的ngx_http_parse_status_line方法可以解析http//响应行，它的输入就是收到的字符流和上下文中的ngx_http_status_t结构    rc = ngx_http_parse_status_line(r, &u->buffer, &ctx->status);    //返回NGX_AGAIN表示还没有解析出完整的http响应行，需要接收更多的//字符流再来解析    if (rc == NGX_AGAIN)    {        return rc;    }    //返回NGX_ERROR则没有接收到合法的http响应行    if (rc == NGX_ERROR)    {        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,                      "upstream sent no valid HTTP/1.0 header");        r->http_version = NGX_HTTP_VERSION_9;        u->state->status = NGX_HTTP_OK;        return NGX_OK;    }    //以下表示解析到完整的http响应行，这时会做一些简单的赋值操作，将解析出//的信息设置到r->upstream->headers_in结构体中，upstream解析完所//有的包头时，就会把headers_in中的成员设置到将要向下游发送的//r->headers_out结构体中，也就是说，现在我们向headers_in中设置的//信息，最终都会发往下游客户端。为什么不是直接设置r->headers_out而要//这样多此一举呢？这是因为upstream希望能够按照//ngx_http_upstream_conf_t配置结构体中的hide_headers等成员对//发往下游的响应头部做统一处理    if (u->state)    {        u->state->status = ctx->status.code;    }    u->headers_in.status_n = ctx->status.code;    len = ctx->status.end - ctx->status.start;    u->headers_in.status_line.len = len;    u->headers_in.status_line.data = ngx_pnalloc(r->pool, len);    if (u->headers_in.status_line.data == NULL)    {        return NGX_ERROR;    }    ngx_memcpy(u->headers_in.status_line.data, ctx->status.start, len);    //下一步将开始解析http头部，设置process_header回调方法为//mytest_upstream_process_header，//之后再收到的新字符流将由mytest_upstream_process_header解析    u->process_header = mytest_upstream_process_header;    //如果本次收到的字符流除了http响应行外，还有多余的字符，//将由mytest_upstream_process_header方法解析    return mytest_upstream_process_header(r);}static ngx_int_tmytest_upstream_process_header(ngx_http_request_t *r){    ngx_int_t                       rc;    ngx_table_elt_t                *h;    ngx_http_upstream_header_t     *hh;    ngx_http_upstream_main_conf_t  *umcf;    //这里将upstream模块配置项ngx_http_upstream_main_conf_t取了//出来，目的只有1个，对将要转发给下游客户端的http响应头部作统一//处理。该结构体中存储了需要做统一处理的http头部名称和回调方法    umcf = ngx_http_get_module_main_conf(r, ngx_http_upstream_module);    //循环的解析所有的http头部    for ( ;; )    {        // http框架提供了基础性的ngx_http_parse_header_line//方法，它用于解析http头部        rc = ngx_http_parse_header_line(r, &r->upstream->buffer, 1);        //返回NGX_OK表示解析出一行http头部        if (rc == NGX_OK)        {            //向headers_in.headers这个ngx_list_t链表中添加http头部            h = ngx_list_push(&r->upstream->headers_in.headers);            if (h == NULL)            {                return NGX_ERROR;            }            //以下开始构造刚刚添加到headers链表中的http头部            h->hash = r->header_hash;            h->key.len = r->header_name_end - r->header_name_start;            h->value.len = r->header_end - r->header_start;            //必须由内存池中分配存放http头部的内存            h->key.data = ngx_pnalloc(r->pool,                                      h->key.len + 1 + h->value.len + 1 + h->key.len);            if (h->key.data == NULL)            {                return NGX_ERROR;            }            h->value.data = h->key.data + h->key.len + 1;            h->lowcase_key = h->key.data + h->key.len + 1 + h->value.len + 1;            ngx_memcpy(h->key.data, r->header_name_start, h->key.len);            h->key.data[h->key.len] = '\0';            ngx_memcpy(h->value.data, r->header_start, h->value.len);            h->value.data[h->value.len] = '\0';            if (h->key.len == r->lowcase_index)            {                ngx_memcpy(h->lowcase_key, r->lowcase_header, h->key.len);            }            else            {                ngx_strlow(h->lowcase_key, h->key.data, h->key.len);            }            //upstream模块会对一些http头部做特殊处理            hh = ngx_hash_find(&umcf->headers_in_hash, h->hash,                               h->lowcase_key, h->key.len);            if (hh && hh->handler(r, h, hh->offset) != NGX_OK)            {                return NGX_ERROR;            }            continue;        }        //返回NGX_HTTP_PARSE_HEADER_DONE表示响应中所有的http头部都解析//完毕，接下来再接收到的都将是http包体        if (rc == NGX_HTTP_PARSE_HEADER_DONE)        {            //如果之前解析http头部时没有发现server和date头部，以下会            //根据http协议添加这两个头部            if (r->upstream->headers_in.server == NULL)            {                h = ngx_list_push(&r->upstream->headers_in.headers);                if (h == NULL)                {                    return NGX_ERROR;                }                h->hash = ngx_hash(ngx_hash(ngx_hash(ngx_hash(                                                         ngx_hash('s', 'e'), 'r'), 'v'), 'e'), 'r');                ngx_str_set(&h->key, "Server");                ngx_str_null(&h->value);                h->lowcase_key = (u_char *) "server";            }            if (r->upstream->headers_in.date == NULL)            {                h = ngx_list_push(&r->upstream->headers_in.headers);                if (h == NULL)                {                    return NGX_ERROR;                }                h->hash = ngx_hash(ngx_hash(ngx_hash('d', 'a'), 't'), 'e');                ngx_str_set(&h->key, "Date");                ngx_str_null(&h->value);                h->lowcase_key = (u_char *) "date";            }            return NGX_OK;        }        //如果返回NGX_AGAIN则表示状态机还没有解析到完整的http头部，//要求upstream模块继续接收新的字符流再交由process_header//回调方法解析        if (rc == NGX_AGAIN)        {            return NGX_AGAIN;        }        //其他返回值都是非法的        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,                      "upstream sent invalid header");        return NGX_HTTP_UPSTREAM_INVALID_HEADER;    }}static voidmytest_upstream_finalize_request(ngx_http_request_t *r, ngx_int_t rc){    ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0,                  "mytest_upstream_finalize_request");}static char *ngx_http_mytest(ngx_conf_t *cf, ngx_command_t *cmd, void *conf){    ngx_http_core_loc_conf_t  *clcf;    //首先找到mytest配置项所属的配置块，clcf貌似是location块内的数据//结构，其实不然，它可以是main、srv或者loc级别配置项，也就是说在每个//http{}和server{}内也都有一个ngx_http_core_loc_conf_t结构体    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);    //http框架在处理用户请求进行到NGX_HTTP_CONTENT_PHASE阶段时，如果//请求的主机域名、URI与mytest配置项所在的配置块相匹配，就将调用我们//实现的ngx_http_mytest_handler方法处理这个请求    clcf->handler = ngx_http_mytest_handler;    return NGX_CONF_OK;}static ngx_int_tngx_http_mytest_handler(ngx_http_request_t *r){    //首先建立http上下文结构体ngx_http_mytest_ctx_t    ngx_http_mytest_ctx_t* myctx = ngx_http_get_module_ctx(r, ngx_http_mytest_module);    if (myctx == NULL)    {        myctx = ngx_palloc(r->pool, sizeof(ngx_http_mytest_ctx_t));        if (myctx == NULL)        {            return NGX_ERROR;        }        //将新建的上下文与请求关联起来        ngx_http_set_ctx(r, myctx, ngx_http_mytest_module);    }    //对每1个要使用upstream的请求，必须调用且只能调用1次//ngx_http_upstream_create方法，它会初始化r->upstream成员    if (ngx_http_upstream_create(r) != NGX_OK)    {        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "ngx_http_upstream_create() failed");        return NGX_ERROR;    }    //得到配置结构体ngx_http_mytest_conf_t    ngx_http_mytest_conf_t  *mycf = (ngx_http_mytest_conf_t  *) ngx_http_get_module_loc_conf(r, ngx_http_mytest_module);    ngx_http_upstream_t *u = r->upstream;    //这里用配置文件中的结构体来赋给r->upstream->conf成员    u->conf = &mycf->upstream;    //决定转发包体时使用的缓冲区    u->buffering = mycf->upstream.buffering;    //以下代码开始初始化resolved结构体，用来保存上游服务器的地址    u->resolved = (ngx_http_upstream_resolved_t*) ngx_pcalloc(r->pool, sizeof(ngx_http_upstream_resolved_t));    if (u->resolved == NULL)    {        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,                      "ngx_pcalloc resolved error. %s.", strerror(errno));        return NGX_ERROR;    }    //这里的上游服务器就是www.google.com    static struct sockaddr_in backendSockAddr;    struct hostent *pHost = gethostbyname((char*) "www.google.com");    if (pHost == NULL)    {        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,                      "gethostbyname fail. %s", strerror(errno));        return NGX_ERROR;    }    //访问上游服务器的80端口    backendSockAddr.sin_family = AF_INET;    backendSockAddr.sin_port = htons((in_port_t) 80);    char* pDmsIP = inet_ntoa(*(struct in_addr*) (pHost->h_addr_list[0]));    backendSockAddr.sin_addr.s_addr = inet_addr(pDmsIP);    myctx->backendServer.data = (u_char*)pDmsIP;    myctx->backendServer.len = strlen(pDmsIP);    //将地址设置到resolved成员中    u->resolved->sockaddr = (struct sockaddr *)&backendSockAddr;    u->resolved->socklen = sizeof(struct sockaddr_in);    u->resolved->naddrs = 1;    //设置三个必须实现的回调方法，也就是5.3.3节至5.3.5节中实现的3个方法    u->create_request = mytest_upstream_create_request;    u->process_header = mytest_process_status_line;    u->finalize_request = mytest_upstream_finalize_request;    //这里必须将count成员加1，理由见5.1.5节    r->main->count++;    //启动upstream    ngx_http_upstream_init(r);    //必须返回NGX_DONE    return NGX_DONE;}

安装脚本

root@VM_12_197_centos nginx-1.5.6]# cat make_upstream.sh #!/bin/shrm -rf /usr/local/nginx_upstreammake clean./configure --prefix=/usr/local/nginx_upstream --add-module=/root/haoning/mygit/mynginxmodule/mynginx/source/chapter5/upstream --with-debugmake make installcp -f /root/haoning/mygit/mynginxmodule/mynginx/source/chapter5/upstream/nginx.conf /usr/local/nginx_upstream/conf[root@VM_12_197_centos nginx-1.5.6]# 

访问http://localhost:8080/test
会跳到google