nginx日志模块ngx_http_log_module源码分析
ngx_http_log_module.c文件
在nginx.conf中相关的指令为：
log_format proxyformat "$time_iso8601 $remote_addr:$remote_port $server_addr:$server_port $upstream_addr $request_time $upstream_response_time $status $upstream_status $request_leng
th $body_bytes_sent \"$request_method $scheme://$http_host$request_uri $server_protocol\" \"$http_referer\" \"$http_user_agent\"";
access_log syslog:facility=local3,severity=info,server=127.0.0.1:514,tag=tengine proxyformat;
先关注log模块的初始化
static ngx_http_module_t ngx_http_log_module_ctx = {
NULL, /* preconfiguration */
ngx_http_log_init, /* postconfiguration */
ngx_http_log_create_main_conf, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
ngx_http_log_create_loc_conf, /* create location configuration */
ngx_http_log_merge_loc_conf /* merge location configuration */
};
static void *
ngx_http_log_create_main_conf(ngx_conf_t *cf)
{
ngx_http_log_main_conf_t *conf;
ngx_http_log_fmt_t *fmt;
conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_log_main_conf_t));
if (conf == NULL) {
return NULL;
}
// 初始化format
if (ngx_array_init(&conf->formats, cf->pool, 4, sizeof(ngx_http_log_fmt_t))
!= NGX_OK)
{
return NULL;
}
return conf;
}
static ngx_int_t
ngx_http_log_init(ngx_conf_t *cf)
{
// 这块有判断是否使用默认的combine的逻辑，在tengine中，自定义了一波，所以不care
// 将handler加入log阶段
cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
h = ngx_array_push(&cmcf->phases[NGX_HTTP_LOG_PHASE].handlers);
if (h == NULL) {
return NGX_ERROR;
}
*h = ngx_http_log_handler;
return NGX_OK;
}
而在log_format指令的处理函数中，将这个fmt给保存下来
static char *
ngx_http_log_set_format(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
// 获取loc_main_conf
ngx_http_log_main_conf_t *lmcf = conf;
// 初始化fmt
fmt = lmcf->formats.elts;
fmt = ngx_array_push(&lmcf->formats);
if (fmt == NULL) {
return NGX_CONF_ERROR;
}
// 赋值name
fmt->name = value[1];
// 初始化flushes和ops
fmt->flushes = ngx_array_create(cf->pool, 4, sizeof(ngx_int_t));
if (fmt->flushes == NULL) {
return NGX_CONF_ERROR;
}
fmt->ops = ngx_array_create(cf->pool, 16, sizeof(ngx_http_log_op_t));
if (fmt->ops == NULL) {
return NGX_CONF_ERROR;
}
// 最后把整个日志格式编译
return ngx_http_log_compile_format(cf, fmt->flushes, fmt->ops, cf->args, 2);
}
static char *
ngx_http_log_compile_format(ngx_conf_t *cf, ngx_array_t *flushes,
ngx_array_t *ops, ngx_array_t *args, ngx_uint_t s)
{
// 遍历所有的args
for ( /* void */ ; s < args->nelts; s++) {
// 在已有的ngx_http_log_vars中看有没有指定的日志格式
for (v = ngx_http_log_vars; v->name.len; v++) {
if (v->name.len == var.len
&& ngx_strncmp(v->name.data, var.data, var.len) == 0)
{
// 将对应的方法，长度赋值给对应op，等待写入
op->len = v->len;
op->getlen = NULL;
op->run = v->run;
op->data = 0;
goto found;
}
}
// 没有的话则调用该函数
if (ngx_http_log_variable_compile(cf, op, &var) != NGX_OK) {
return NGX_CONF_ERROR;
}
if (len) {
op->len = len;
op->getlen = NULL;
// 如果长度小的话，就直接用data来记录
if (len <= sizeof(uintptr_t)) {
op->run = ngx_http_log_copy_short;
op->data = 0;
// 记录data
while (len--) {
op->data <<= 8;
op->data |= data[len];
}
// 比较长的话，记录成指针来指向，函数也是获取指针来进行获取值
} else {
op->run = ngx_http_log_copy_long;
p = ngx_pnalloc(cf->pool, len);
if (p == NULL) {
return NGX_CONF_ERROR;
}
ngx_memcpy(p, data, len);
op->data = (uintptr_t) p;
}
}
}
static ngx_int_t
ngx_http_log_variable_compile(ngx_conf_t *cf, ngx_http_log_op_t *op,
ngx_str_t *value)
{
ngx_int_t index;
index = ngx_http_get_variable_index(cf, value);
op->len = 0;
op->getlen = ngx_http_log_variable_getlen;
op->run = ngx_http_log_variable;
op->data = index;
}
// 而这些可以进入日志中的参数，则是在core_preconfiguration函数中的ngx_http_variables_add_core_vars函数
ngx_int_t
ngx_http_variables_add_core_vars(ngx_conf_t *cf)
{
cmcf->variables_keys = ngx_pcalloc(cf->temp_pool,
sizeof(ngx_hash_keys_arrays_t));
for (cv = ngx_http_core_variables; cv->name.len; cv++) {
v = ngx_palloc(cf->pool, sizeof(ngx_http_variable_t));
if (v == NULL) {
return NGX_ERROR;
}
*v = *cv;
rc = ngx_hash_add_key(cmcf->variables_keys, &v->name, v,
NGX_HASH_READONLY_KEY);
if (rc == NGX_OK) {
continue;
}
if (rc == NGX_BUSY) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"conflicting variable name \"%V\"", &v->name);
}
return NGX_ERROR;
}
接下来可以看下整个的ngx_http_core_variables
static ngx_http_variable_t ngx_http_core_variables[] = {
{ ngx_string("http_host"), NULL, ngx_http_variable_header,
offsetof(ngx_http_request_t, headers_in.host), 0, 0 },
{ ngx_string("http_user_agent"), NULL, ngx_http_variable_header,
offsetof(ngx_http_request_t, headers_in.user_agent), 0, 0 },
{ ngx_string("http_referer"), NULL, ngx_http_variable_header,
offsetof(ngx_http_request_t, headers_in.referer), 0, 0 },
#if (NGX_HTTP_GZIP)
{ ngx_string("http_via"), NULL, ngx_http_variable_header,
offsetof(ngx_http_request_t, headers_in.via), 0, 0 },
#endif
#if (NGX_HTTP_X_FORWARDED_FOR)
{ ngx_string("http_x_forwarded_for"), NULL, ngx_http_variable_headers,
offsetof(ngx_http_request_t, headers_in.x_forwarded_for), 0, 0 },
#endif
{ ngx_string("http_cookie"), NULL, ngx_http_variable_cookies,
offsetof(ngx_http_request_t, headers_in.cookies), 0, 0 },
{ ngx_string("content_length"), NULL, ngx_http_variable_content_length,
0, 0, 0 },
{ ngx_string("content_type"), NULL, ngx_http_variable_header,
offsetof(ngx_http_request_t, headers_in.content_type), 0, 0 },
{ ngx_string("host"), NULL, ngx_http_variable_host, 0, 0, 0 },
{ ngx_string("binary_remote_addr"), NULL,
ngx_http_variable_binary_remote_addr, 0, 0, 0 },
{ ngx_string("remote_addr"), NULL, ngx_http_variable_remote_addr, 0, 0, 0 },
{ ngx_string("remote_port"), NULL, ngx_http_variable_remote_port, 0, 0, 0 },
{ ngx_string("proxy_protocol_addr"), NULL,
ngx_http_variable_proxy_protocol_addr, 0, 0, 0 },
{ ngx_string("server_addr"), NULL, ngx_http_variable_server_addr, 0, 0, 0 },
{ ngx_string("server_port"), NULL, ngx_http_variable_server_port, 0, 0, 0 },
{ ngx_string("server_protocol"), NULL, ngx_http_variable_request,
offsetof(ngx_http_request_t, http_protocol), 0, 0 },
{ ngx_string("scheme"), NULL, ngx_http_variable_scheme, 0, 0, 0 },
{ ngx_string("https"), NULL, ngx_http_variable_https, 0, 0, 0 },
{ ngx_string("full_request"), NULL, ngx_http_variable_full_request,
0, 0, 0 },
{ ngx_string("normalized_request"), NULL, ngx_http_variable_normalized_request,
0, 0, 0 },
{ ngx_string("request_uri"), NULL, ngx_http_variable_request,
offsetof(ngx_http_request_t, unparsed_uri), 0, 0 },
{ ngx_string("raw_uri"), NULL, ngx_http_variable_request,
offsetof(ngx_http_request_t, raw_uri), 0, 0 },
{ ngx_string("uri"), NULL, ngx_http_variable_request,
offsetof(ngx_http_request_t, uri),
NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("document_uri"), NULL, ngx_http_variable_request,
offsetof(ngx_http_request_t, uri),
NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("request"), NULL, ngx_http_variable_request_line, 0, 0, 0 },
{ ngx_string("document_root"), NULL,
ngx_http_variable_document_root, 0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("realpath_root"), NULL,
ngx_http_variable_realpath_root, 0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("query_string"), NULL, ngx_http_variable_request,
offsetof(ngx_http_request_t, args),
NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("args"),
ngx_http_variable_set_args,
ngx_http_variable_request,
offsetof(ngx_http_request_t, args),
NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("is_args"), NULL, ngx_http_variable_is_args,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("request_filename"), NULL,
ngx_http_variable_request_filename, 0,
NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("server_name"), NULL, ngx_http_variable_server_name, 0, 0, 0 },
{ ngx_string("request_method"), NULL,
ngx_http_variable_request_method, 0,
NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("remote_user"), NULL, ngx_http_variable_remote_user, 0, 0, 0 },
{ ngx_string("bytes_sent"), NULL, ngx_http_variable_bytes_sent,
0, 0, 0 },
{ ngx_string("body_bytes_sent"), NULL, ngx_http_variable_body_bytes_sent,
0, 0, 0 },
{ ngx_string("pipe"), NULL, ngx_http_variable_pipe,
0, 0, 0 },
{ ngx_string("request_completion"), NULL,
ngx_http_variable_request_completion,
0, 0, 0 },
{ ngx_string("request_body"), NULL,
ngx_http_variable_request_body,
0, 0, 0 },
{ ngx_string("request_body_file"), NULL,
ngx_http_variable_request_body_file,
0, 0, 0 },
{ ngx_string("request_length"), NULL, ngx_http_variable_request_length,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("request_time"), NULL, ngx_http_variable_request_time,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("status"), NULL,
ngx_http_variable_status, 0,
NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("sent_http_content_type"), NULL,
ngx_http_variable_sent_content_type, 0, 0, 0 },
{ ngx_string("sent_http_content_length"), NULL,
ngx_http_variable_sent_content_length, 0, 0, 0 },
{ ngx_string("sent_http_location"), NULL,
ngx_http_variable_sent_location, 0, 0, 0 },
{ ngx_string("sent_http_last_modified"), NULL,
ngx_http_variable_sent_last_modified, 0, 0, 0 },
{ ngx_string("sent_http_connection"), NULL,
ngx_http_variable_sent_connection, 0, 0, 0 },
{ ngx_string("sent_http_keep_alive"), NULL,
ngx_http_variable_sent_keep_alive, 0, 0, 0 },
{ ngx_string("sent_http_transfer_encoding"), NULL,
ngx_http_variable_sent_transfer_encoding, 0, 0, 0 },
{ ngx_string("sent_http_cache_control"), NULL, ngx_http_variable_headers,
offsetof(ngx_http_request_t, headers_out.cache_control), 0, 0 },
{ ngx_string("limit_rate"), ngx_http_variable_request_set_size,
ngx_http_variable_request_get_size,
offsetof(ngx_http_request_t, limit_rate),
NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("connection"), NULL,
ngx_http_variable_connection, 0, 0, 0 },
{ ngx_string("connection_requests"), NULL,
ngx_http_variable_connection_requests, 0, 0, 0 },
{ ngx_string("nginx_version"), NULL, ngx_http_variable_nginx_version,
0, 0, 0 },
{ ngx_string("hostname"), NULL, ngx_http_variable_hostname,
0, 0, 0 },
{ ngx_string("pid"), NULL, ngx_http_variable_pid,
0, 0, 0 },
{ ngx_string("msec"), NULL, ngx_http_variable_msec,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("dollar"), NULL, ngx_http_variable_dollar,
0, 0, 0 },
{ ngx_string("host_comment"), NULL, ngx_http_variable_host_comment,
0, 0, 0 },
{ ngx_string("unix_time"), NULL, ngx_http_variable_unix_time,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("year"), NULL, ngx_http_variable_year,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("year2"), NULL, ngx_http_variable_year2,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("month"), NULL, ngx_http_variable_month,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("day"), NULL, ngx_http_variable_day,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("hour"), NULL, ngx_http_variable_hour,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("hour12"), NULL, ngx_http_variable_hour12,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("minute"), NULL, ngx_http_variable_minute,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("second"), NULL, ngx_http_variable_second,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("time_iso8601"), NULL, ngx_http_variable_time_iso8601,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("time_local"), NULL, ngx_http_variable_time_local,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("time_http"), NULL, ngx_http_variable_time_http,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
#if (NGX_HAVE_TCP_INFO)
{ ngx_string("tcpinfo_rtt"), NULL, ngx_http_variable_tcpinfo,
0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("tcpinfo_rttvar"), NULL, ngx_http_variable_tcpinfo,
1, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("tcpinfo_snd_cwnd"), NULL, ngx_http_variable_tcpinfo,
2, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("tcpinfo_rcv_space"), NULL, ngx_http_variable_tcpinfo,
3, NGX_HTTP_VAR_NOCACHEABLE, 0 },
#endif
{ ngx_null_string, NULL, NULL, 0, 0, 0 }
};
这块是在ngx_http_variables_init_vars中初始化
ngx_int_t
ngx_http_variables_init_vars(ngx_conf_t *cf)
{
cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
v = cmcf->variables.elts;
key = cmcf->variables_keys->keys.elts;
for (i = 0; i < cmcf->variables.nelts; i++) {
for (n = 0; n < cmcf->variables_keys->keys.nelts; n++) {
av = key[n].value;
if (v[i].name.len == key[n].key.len
&& ngx_strncmp(v[i].name.data, key[n].key.data, v[i].name.len)
== 0)
{
// 将get_handler和data赋值过来
v[i].get_handler = av->get_handler;
v[i].data = av->data;
}