nginx调试日志的几种方法

最简单的方式就是

fprintf(stderr, "haoning hahahah:%s\r\n","ningning");

或者

 ngx_log_stderr(0,"haoning: ngx_http_hello_world_handler\"%s\"","haohao" );

但是如果打印

ngx_log_stderr(0,"haoning haohao subrequest in memory: %d", (int) r->subrequest_in_memory);
ngx_log_stderr(0,"haoning haohao  r->method : %d",(int) r->method);
ngx_log_stderr(0,"haoning haohao r->http_version: %d",(int) r->http_version) ;
ngx_log_stderr(0,"haoning haohao r->request_line.data: %s",r->request_line.data) ;
ngx_log_stderr(0,"haoning haohao r->uri.data): %s",r->uri.data);
ngx_log_stderr(0,"haoning haohao r->args.data: %s",r->args.data);
ngx_log_stderr(0,"haoning haohao r->unparsed_uri.data: %s",r->unparsed_uri.data);
ngx_log_stderr(0,"haoning haohao r->method_name.data: %s",r->method_name.data)  ;
ngx_log_stderr(0,"haoning haohao r->http_protocol.data: %s",r->http_protocol.data);
ngx_log_stderr(0,"haoning haohao r->exten.data: %s",r->exten.data);

会报错

参考章亦春的echo
http://wiki.nginx.org/HttpEchoModule

源码中有个ddebug.h里面定义的打印log都输出到stderr
所以在这个模块的源码中把开头的

#ifndef DDEBUG
#define DDEBUG 0
#endif

改成

#ifndef DDEBUG
#define DDEBUG 1
#endif

当启动nginx的时候就输出log了 类似

e.c line 463.
echo *** ngx_http_echo_helper: filter used = 1 at /root/hellogit/hello/graphviz/nginx/mymodule/echo-nginx-module-0.48/src/ngx_http_echo_module.c line 324.
echo *** ngx_http_echo_helper: found raw arg hello at /root/hellogit/hello/graphviz/nginx/mymodule/echo-nginx-module-0.48/src/ngx_http_echo_module.c line 358.
echo *** ngx_http_echo_echo_before_body: processing echo_before_body directive... at /root/hellogit/hello/graphviz/nginx/mymodule/echo-nginx-module-0.48/src/ngx_http_echo_module.c line 463.
echo *** ngx_http_echo_helper: found raw arg world at /root/hellogit/hello/graphviz/nginx/mymodule/echo-nginx-module-0.48/src/ngx_http_echo_module.c line 358.
echo *** ngx_http_echo_helper: filter used = 1 at /root/hellogit/hello/graphviz/nginx/mymodule/echo-nginx-module-0.48/src/ngx_http_echo_module.c line 324.
echo *** ngx_http_echo_helper: found raw arg hiya at /root/hellogit/hello/graphviz/nginx/mymodule/echo-nginx-module-0.48/src/ngx_http_echo_module.c line 358.
echo *** ngx_http_echo_helper: found raw arg igor at /root/hellogit/hello/graphviz/nginx/mymodule/echo-nginx-module-0.48/src/ngx_http_echo_module.c line 358.

可以重定向
./nginx >a.log 2>&1

★★★★★★第二种方法★★★★★★
还有一种是通用的 打印log的方法，跟nginx没关系
任何都适用，定义haolog.c   haolog.h 在ngx_http_echo_module.c中引用haolog.h

/root/hellogit/hello/graphviz/nginx/mymodule/echo
[root@VM_253_237_tlinux echo]# ls
config  haolog.c  haolog.h  nginx.conf  ngx_http_echo_module.c  shuoming.txt
[root@VM_253_237_tlinux echo]# 

config中标记新增的源码.c 和依赖的.h

ngx_addon_name=ngx_http_echo_module
HTTP_MODULES="$HTTP_MODULES ngx_http_echo_module"
NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_echo_module.c $ngx_addon_dir/haolog.c"
NGX_ADDON_DEPS="$NGX_ADDON_DEPS $ngx_addon_dir/haolog.h"
CORE_LIBS="$CORE_LIBS -lpcre"

log代码如下

[root@VM_253_237_tlinux echo]# cat  haolog.h

#include <stdio.h>
#include <time.h>
#define DEBUG_LOG( str ) log_append_to_file("/root/hellogit/hello/graphviz/nginx/mymodule/mylog/test.log", str,__FILE__,__LINE__ );
void log_append_to_file(char* filename,char* str,char* sourceFile,int fileLine);
[root@VM_253_237_tlinux echo]

haolog.c:

[root@VM_253_237_tlinux echo]# cat haolog.c 
#include <stdio.h>
#include <time.h>
#define DEBUG_LOG( str ) log_append_to_file("/root/hellogit/hello/graphviz/nginx/mymodule/mylog/test.log", str,__FILE__,__LINE__ );  
void log_append_to_file(char* filename,char* str,char* sourceFile,int fileLine)
{
        time_t t;
        time(&t);
        struct tm* tp= localtime(&t);
        char now_str[100];
        strftime(now_str, 100, "%Y-%m-%d %H:%M:%S", tp);
        FILE *fo;
        fo = fopen(filename, "a");
    if (fo == 0) {
        return;
    }
        fprintf(fo, "%s %s(:%d):%s\r\n",now_str,sourceFile,fileLine, str);
        fclose(fo);
}

//int main(int argc, char **argv)
//{
///*********************define******************/
//
//        DEBUG_LOG("haoning----logmain.c");
//        printf("Hello World!\n");
//        return 0;
//} 
[root@VM_253_237_tlinux echo]# 

完整的nginx模块如下

[root@VM_253_237_tlinux echo]# cat ngx_http_echo_module.c 
/*
* Copyright (C) fabricehao
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include <time.h>
#include "haolog.h"

/* Module config */
typedef struct {
    ngx_str_t  ed;
} ngx_http_echo_loc_conf_t;
static char *ngx_http_echo(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static void *ngx_http_echo_create_loc_conf(ngx_conf_t *cf);
static char *ngx_http_echo_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child);
/* Directives */
static ngx_command_t  ngx_http_echo_commands[] = {
        { 
                ngx_string("echo"),
        NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
        ngx_http_echo,
        NGX_HTTP_LOC_CONF_OFFSET,
        offsetof(ngx_http_echo_loc_conf_t, ed),
        NULL 
        },
    ngx_null_command
};
/* Http context of the module */
static ngx_http_module_t  ngx_http_echo_module_ctx = {
    NULL,                                  /* preconfiguration */
    NULL,                                  /* postconfiguration */
    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */
    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */
    ngx_http_echo_create_loc_conf,         /* create location configration */
    ngx_http_echo_merge_loc_conf           /* merge location configration */
};
/* Module */
ngx_module_t  ngx_http_echo_module = {
    NGX_MODULE_V1,
    &ngx_http_echo_module_ctx,             /* module context */
    ngx_http_echo_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
};
/* Handler function */
static ngx_int_t
ngx_http_echo_handler(ngx_http_request_t *r)
{
        DEBUG_LOG("haoning.........ngx_http_echo_handler");
    ngx_int_t rc;
    ngx_buf_t *b;
    ngx_chain_t out;
    ngx_http_echo_loc_conf_t *elcf;
    elcf = ngx_http_get_module_loc_conf(r, ngx_http_echo_module);
    if(!(r->method & (NGX_HTTP_HEAD|NGX_HTTP_GET|NGX_HTTP_POST)))
    {
        return NGX_HTTP_NOT_ALLOWED;
    }
    r->headers_out.content_type.len = sizeof("text/html") - 1;
    r->headers_out.content_type.data = (u_char *) "text/html";
    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.content_length_n = elcf->ed.len;
    if(r->method == NGX_HTTP_HEAD)
    {
                DEBUG_LOG("haoning......ngx_http_echo_handlerr---r->method == NGX_HTTP_HEAD");
        rc = ngx_http_send_header(r);
        if(rc != NGX_OK)
        {
            return rc;
        }
    }
    b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
    if(b == NULL)
    {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "Failed to allocate response buffer.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    out.buf = b;
    out.next = NULL;
    b->pos = elcf->ed.data;
    b->last = elcf->ed.data + (elcf->ed.len);
    b->memory = 1;
    b->last_buf = 1;
    rc = ngx_http_send_header(r);
    if(rc != NGX_OK)
    {
        return rc;
    }
        DEBUG_LOG("haoning......ngx_http_output_filter");
    return ngx_http_output_filter(r, &out);
}
static char *
ngx_http_echo(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
        DEBUG_LOG("haoning --ngx_http_echo->>>>> init");
    ngx_http_core_loc_conf_t  *clcf;
    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
    clcf->handler = ngx_http_echo_handler;
    ngx_conf_set_str_slot(cf,cmd,conf);
    return NGX_CONF_OK;
}
static void *
ngx_http_echo_create_loc_conf(ngx_conf_t *cf)
{
        DEBUG_LOG("haoning --ngx_http_echo_create_loc_conf");
    ngx_http_echo_loc_conf_t  *conf;
    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_echo_loc_conf_t));
    if (conf == NULL) {
        return NGX_CONF_ERROR;
    }
    conf->ed.len = 0;
    conf->ed.data = NULL;
    return conf;
}
static char *
ngx_http_echo_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
{
        DEBUG_LOG("haoning --ngx_http_echo_merge_loc_conf");
    ngx_http_echo_loc_conf_t *prev = parent;
    ngx_http_echo_loc_conf_t *conf = child;
    ngx_conf_merge_str_value(conf->ed, prev->ed, "");
    return NGX_CONF_OK;
}
[root@VM_253_237_tlinux echo]# 

调用
DEBUG_LOG("haoning --ngx_http_echo_merge_loc_conf");
就打印到自定义的
/root/hellogit/hello/graphviz/nginx/mymodule/mylog/test.log


疑问，handler里的怎么打印不出来？？？？