feat: support customize http log format (#116)

README.md

@@ -64,9 +64,10 @@ OPTIONS:
         --render-index           Serve index.html when requesting a directory, returns 404 if not found index.html
         --render-try-index       Serve index.html when requesting a directory, returns directory listing if not found index.html
         --render-spa             Serve SPA(Single Page Application)
-        --completions <shell>    Print shell completion script for <shell> [possible values: bash, elvish, fish, powershell, zsh]
         --tls-cert <path>        Path to an SSL/TLS certificate to serve with HTTPS
         --tls-key <path>         Path to the SSL/TLS certificate's private key
+        --log-format <format>    Customize http log format
+        --completions <shell>    Print shell completion script for <shell> [possible values: bash, elvish, fish, powershell, zsh]
     -h, --help                   Print help information
     -V, --version                Print version information
 ```
@@ -187,6 +188,23 @@ dufs -a /@admin:pass1@* -a /ui@designer:pass2 -A
 - Account `admin:pass1` can upload/delete/view/download any files/folders.
 - Account `designer:pass2` can upload/delete/view/download any files/folders in the `ui` folder.
 
+## Log format
+
+dufs supports customize http log format via option `--log-format`.
+
+The default format is `$remote_addr "$request" $status`.
+
+All variables list below:
+
+| name         | description                                                               |
+| ------------ | ------------------------------------------------------------------------- |
+| $remote_addr | client address                                                            |
+| $remote_user | user name supplied with authentication                                    |
+| $request     | full original request line                                                |
+| $status      | response status                                                           |
+| $http_       | arbitrary request header field. examples: $http_user_agent, $http_referer |
+
+> use `dufs --log-format=''` to disable http log
 ## License
 
 Copyright (c) 2022 dufs-developers.