未来的日志要做web server从apache到nginx的转换，
主要的工作就是日志格式还有rewrite以及虚拟主机的转换。
以下是我查阅到的比较有用的配置资料和一些总结：
1、apache的LogFormat选项（配置参数/内置变量）：
(来自：http://httpd.apache.org/docs/2.2/mod/mod_log_config.html#formats)
The characteristics of the request itself are logged by placing "%" directives in the format string, which are replaced in the log file by the values as follows:
%% |
The percent sign |
%a |
Remote IP-address |
%A |
Local IP-address |
%B |
Size of response in bytes, excluding HTTP headers. |
%b |
Size of response in bytes, excluding HTTP headers. In CLF format, i.e. a '-' rather than a 0 when no bytes are sent. |
%{Foobar}C |
The contents of cookie Foobar in the request sent to the server. Only version 0 cookies are fully supported. |
%D |
The time taken to serve the request, in microseconds. |
%{FOOBAR}e |
The contents of the environment variable FOOBAR
|
%f |
Filename |
%h |
Remote host |
%H |
The request protocol |
%{Foobar}i |
The contents of Foobar: header line(s) in the request sent to the server. Changes made by other modules (e.g. mod_headers) affect this. If you're interested in what the request header was prior to when most modules would have modified it, use mod_setenvif to copy the header into an internal environment variable and log that value with the %{VARNAME}e described above. |
%k |
Number of keepalive requests handled on this connection. Interesting if KeepAlive is being used, so that, for example, a '1' means the first keepalive request after the initial one, '2' the second, etc...; otherwise this is always 0 (indicating the initial request). Available in versions 2.2.11 and later. |
%l |
Remote logname (from identd, if supplied). This will return a dash unless mod_ident is present and IdentityCheck is set On. |
%m |
The request method |
%{Foobar}n |
The contents of note Foobar from another module. |
%{Foobar}o |
The contents of Foobar: header line(s) in the reply. |
%p |
The canonical port of the server serving the request |
%{format}p |
The canonical port of the server serving the request or the server's actual port or the client's actual port. Valid formats are canonical, local, orremote. |
%P |
The process ID of the child that serviced the request. |
%{format}P |
The process ID or thread id of the child that serviced the request. Valid formats are pid, tid, and hextid. hextid requires APR 1.2.0 or higher. |
%q |
The query string (prepended with a ? if a query string exists, otherwise an empty string) |
%r |
First line of request |
%R |
The handler generating the response (if any). |
%s |
Status. For requests that got internally redirected, this is the status of the *original* request --- %>s for the last. |
%t |
Time the request was received (standard english format) |
%{format}t |
The time, in the form given by format, which should be in strftime(3) format. (potentially localized) |
%T |
The time taken to serve the request, in seconds. |
%u |
Remote user (from auth; may be bogus if return status (%s) is 401) |
%U |
The URL path requested, not including any query string. |
%v |
The canonical ServerName of the server serving the request. |
%V |
The server name according to the UseCanonicalName setting. |
%X |
Connection status when response is completed:
X = |
connection aborted before the response completed. |
+ = |
connection may be kept alive after the response is sent. |
- = |
connection will be closed after the response is sent. |
(This directive was %c in late versions of Apache 1.3, but this conflicted with the historical ssl %{var}c syntax.)
|
%I |
Bytes received, including request and headers, cannot be zero. You need to enable mod_logio to use this. |
%O |
Bytes sent, including headers, cannot be zero. You need to enable mod_logio to use this. |
2、nginx的log_format配置参数（内置变量）：
（来自：http://nginx.org/en/docs/http/ngx_http_log_module.html#log_format）
The log format can contain common variables, and variables that exist only at the time of a log write:
$body_bytes_sent
the number of bytes sent to a client not counting the response header; this variable is compatible with the “%B” parameter of the mod_log_config Apache module
$bytes_sent
the number of bytes sent to a client
$connection
connection serial number
$connection_requests （nginx 1.1.18版本及以后版本才有这个变量）
the current number of requests made through a connection
$msec
time in seconds with a milliseconds resolution at the time of log write
$pipe
“p” if request was pipelined, “.” otherwise
$request_length
request length (including request line, header, and request body)
$request_time
request processing time in seconds with a milliseconds resolution; time elapsed between the first bytes were read from the client and the log write after the last bytes were sent to the client
$status
response status
$time_iso8601
local time in the ISO 8601 standard format
$time_local
local time in the Common Log Format
Header lines sent to a client have the prefix “sent_http_”, for example, $sent_http_content_range.
The configuration always includes the predefined format “combined”:
log_format combined '$remote_addr - $remote_user [$time_local] '
'"$request" $status $body_bytes_sent '
'"$http_referer" "$http_user_agent"';
