docs: more detailed description

Author: dnomd343

README.md

@@ -6,7 +6,7 @@ Using one command to start the Syncplay service. Yes, it's very simple.
 
 ```bash
 > docker run --rm --net=host dnomd343/syncplay
-Welcome to Syncplay server, ver. 1.7.0
+Welcome to Syncplay server, ver. 1.7.1
 ```
 
 > Pressing `Ctrl+C` will exit the service.
@@ -26,13 +26,11 @@ You can add more arguments to achieve customization. For example, we require a p
 > Note that before pressing Enter, you must execute `docker rm -f syncplay` to remove the original services, otherwise they will conflict.
 
 ```bash
-docker run -d --net=host           \
-  --restart=always --name=syncplay \
-  dnomd343/syncplay --disable-chat \
-  --password=PASSWD --motd='HELLO WORLD'
+docker run -d --net=host --restart=always --name=syncplay dnomd343/syncplay \
+  --disable-chat --password=PASSWD --motd='HELLO WORLD'
 ```
 
-The server will be restarted when necessary, or the Docker service or Syncplay may need to be updated. Whether it is expected or not, it is necessary to persist Syncplay at this time, which means that the room data will be saved to disk. You need to choose a working directory to save them, such as `/etc/syncplay/` , execute the following command, the data will be saved to the `rooms.db` file.
+The server will be restarted when necessary, or the Docker service may need to be updated. Whether it is expected or not, it is necessary to persist Syncplay at this time, which means that the room data will be saved to disk. You need to choose a working directory to save them, such as `/etc/syncplay/` , execute the following command, the data will be saved to the `rooms.db` file.
 
 ```bash
 docker run -d --net=host           \
@@ -41,7 +39,7 @@ docker run -d --net=host           \
   dnomd343/syncplay --persistent
 ```
 
-This directory has more uses. For example, adding the `--enable-stats` option will enable the statistics function, and the data will be saved to the file `stats.db` in the directory. You can also create a `config.yml` file in the directory and write the configuration parameters in it, Syncplay will automatically read it when it starts, avoiding the need to type a large number of parameters in the command line.
+This directory has more uses. For example, adding the `--enable-stats` option will enable the statistics function, and the data will be saved to the file `stats.db` in the directory. You can also create a `config.yml` file in the directory and write the configuration options in it, Syncplay will automatically read it when it starts, avoiding the need to type a large number of arguments in the command line.
 
 ```yaml
 # /etc/syncplay/config.yml
@@ -97,7 +95,7 @@ You can customize the Syncplay server by specifying the following command line a
 
 + `--motd [MESSAGE]` ：The welcome text after the user enters the room, not enabled by default.
 
-+ `--salt [SALT]` ：A string used to secure passwords (e.g. Rainbow-tables), defaults to empty.
++ `--salt [TEXT]` ：A string used to secure passwords (e.g. Rainbow-tables), defaults to empty.
 
 + `--random-salt` ：Use a randomly generated salt value, valid when `--salt` is not specified, not enabled by default.
 
@@ -113,49 +111,58 @@ You can customize the Syncplay server by specifying the following command line a
 
 + `--persistent` ：Enable room data persistence, the information will be saved to the `rooms.db` file, only valid when `--isolate-rooms` is not specified, not enabled by default.
 
-+ `--max-username [N]` ：Maximum length of usernames, default is `150` .
++ `--max-username [NUM]` ：Maximum length of usernames, default is `150` .
 
-+ `--max-chat-message [N]` ：Maximum length of chat messages, default is `150` .
++ `--max-chat-message [NUM]` ：Maximum length of chat messages, default is `150` .
 
 + `--permanent-rooms [ROOM ...]` ：Specifies a list of rooms that will still be listed even if their playlist is empty, only valid when `--persistent` is specified, defaults to empty.
 
++ `--listen-ipv4` ：Customize the listening address of the Syncplay service on the IPv4 network, not enabled by default.
+
++ `--listen-ipv6` ：Customize the listening address of the Syncplay service on the IPv6 network, not enabled by default.
+
+> Only when you specify `--listen-ipv4`, Syncplay will not listen on IPv6 and vice versa. When both are specified, Syncplay will work under dual-stack networking.
+
 You can also use the following command to output help information.
 
 ```bash
 > docker run --rm syncplay --help
-usage: syncplay [-h] [-p PORT] [--password PASSWORD] [--motd MOTD]
-                [--salt SALT] [--random-salt] [--isolate-rooms]
+usage: syncplay [-h] [-p PORT] [--password PASSWD] [--motd MESSAGE]
+                [--salt TEXT] [--random-salt] [--isolate-rooms]
                 [--disable-chat] [--disable-ready] [--enable-stats]
-                [--enable-tls] [--persistent] [--max-username MAX_USERNAME]
-                [--max-chat-message MAX_CHAT_MESSAGE]
-                [--permanent-rooms [PERMANENT_ROOMS ...]]
+                [--enable-tls] [--persistent] [--max-username NUM]
+                [--max-chat-message NUM] [--permanent-rooms [ROOM ...]]
+                [--listen-ipv4 INTERFACE] [--listen-ipv6 INTERFACE]
 
 Syncplay Docker Bootstrap
 
-optional arguments:
+options:
   -h, --help            show this help message and exit
   -p PORT, --port PORT  listen port of syncplay server
-  --password PASSWORD   authentication of syncplay server
-  --motd MOTD           welcome text after the user enters the room
-  --salt SALT           string used to secure passwords
+  --password PASSWD     authentication of syncplay server
+  --motd MESSAGE        welcome text after the user enters the room
+  --salt TEXT           string used to secure passwords
   --random-salt         use a randomly generated salt value
   --isolate-rooms       room isolation enabled
   --disable-chat        disables the chat feature
   --disable-ready       disables the readiness indicator feature
   --enable-stats        enable syncplay server statistics
   --enable-tls          enable tls support of syncplay server
   --persistent          enables room persistence
-  --max-username MAX_USERNAME
-                        maximum length of usernames
-  --max-chat-message MAX_CHAT_MESSAGE
+  --max-username NUM    maximum length of usernames
+  --max-chat-message NUM
                         maximum length of chat messages
-  --permanent-rooms [PERMANENT_ROOMS ...]
+  --permanent-rooms [ROOM ...]
                         permanent rooms of syncplay server
+  --listen-ipv4 INTERFACE
+                        listening address of ipv4
+  --listen-ipv6 INTERFACE
+                        listening address of ipv6
 ```
 
 ## Configure File
 
-If you configure a lot of options, it will be quite troublesome and error-prone to enter a large number of command line parameters every time you start. At this time, you can write them into the configuration file. Create a `config.yml` file in the working directory. It uses YAML format and supports all parameters in the command line. Syncplay will automatically read and load it when starting, but it should be noted that if the same parameters are specified on the command line, will override the configuration file's options.
+If you configure a lot of options, it will be quite troublesome and error-prone to enter a large number of command line arguments every time you start. At this time, you can write them into the configuration file. Create a `config.yml` file in the working directory. It uses YAML format and supports all arguments in the command line. Syncplay will automatically read and load it when starting, but it should be noted that if the same arguments are specified on the command line, will override the configuration file's options.
 
 ```yaml
 port: 7999
@@ -170,6 +177,8 @@ disable-chat: true
 disable-ready: true
 max-username: 256
 max-chat-message: 2048
+listen-ipv4: 127.0.0.1
+listen-ipv6: ::1
 permanent-rooms:
   - ROOM_1
   - ROOM_2
@@ -179,6 +188,18 @@ motd: |
   More information...
 ```
 
+## Environment Variables
+
+The Syncplay container also supports configuration through environment variables. It supports three types of fields: numbers, strings, and boolean, this means that `permanent-rooms` is not supported. Environment variables are named in uppercase letters, and `-` is replaced by `_` , boolean values are represented by `ON` or `TRUE`. The following is an example of using environment variables.
+
+```bash
+docker run -d --net=host --restart=always --name=syncplay \
+  --env PORT=7999 --env MOTD=Hello --env DISABLE_READY=ON \
+  dnomd343/syncplay
+```
+
+You may have noticed that we support three configuration methods: command line arguments, configuration file and environment variables. Their priority is from high to low, that is, the command line arguments will override the options of the configuration file, and the configuration file will override the environment variables. You can use them together.
+
 ## Docker Compose
 
 Using `docker-compose` to deploy Syncplay is a more elegant way. You need to create a `docker-compose.yml` configuration file and write the following example.
@@ -202,7 +223,7 @@ We save this file in the `/etc/syncplay/` directory. Since a relative path is us
 > docker-compose up
 Recreating syncplay ... done
 Attaching to syncplay
-syncplay    | Welcome to Syncplay server, ver. 1.7.0
+syncplay    | Welcome to Syncplay server, ver. 1.7.1
 ```
 
 > Adding the `-d` option allows the service to run in the background.
@@ -215,12 +236,30 @@ If you encounter any errors, please first use the `docker logs syncplay` command
 
 ```bash
 > docker run --rm --env DEBUG=ON dnomd343/syncplay
-Command line arguments -> Namespace(port=None, password=None, motd=None, salt=None, random_salt=False, isolate_rooms=False, disable_chat=False, disable_ready=False, enable_stats=False, enable_tls=False, persistent=False, max_username=None, max_chat_message=None, permanent_rooms=None)
-Parsed arguments -> {}
+Bootstrap options -> [('port', <class 'int'>, False), ('password', <class 'str'>, False), ('motd', <class 'str'>, False), ('salt', <class 'str'>, False), ('random_salt', <class 'bool'>, False), ('isolate_rooms', <class 'bool'>, False), ('disable_chat', <class 'bool'>, False), ('disable_ready', <class 'bool'>, False), ('enable_stats', <class 'bool'>, False), ('enable_tls', <class 'bool'>, False), ('persistent', <class 'bool'>, False), ('max_username', <class 'int'>, False), ('max_chat_message', <class 'int'>, False), ('permanent_rooms', <class 'str'>, True), ('listen_ipv4', <class 'str'>, False), ('listen_ipv6', <class 'str'>, False)]
+Environment variables -> environ({'PATH': '/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin', 'HOSTNAME': '0a28a2e2ea50', 'DEBUG': 'ON', 'LANG': 'C.UTF-8', 'GPG_KEY': 'A035C8C19219BA821ECEA86B64E628F8D684696D', 'PYTHON_VERSION': '3.10.13', 'PYTHON_PIP_VERSION': '23.0.1', 'PYTHON_SETUPTOOLS_VERSION': '65.5.1', 'PYTHON_GET_PIP_URL': 'https://github.com/pypa/get-pip/raw/4cfa4081d27285bda1220a62a5ebf5b4bd749cdb/public/get-pip.py', 'PYTHON_GET_PIP_SHA256': '9cc01665956d22b3bf057ae8287b035827bfd895da235bcea200ab3b811790b6', 'PYTHONUNBUFFERED': '1', 'HOME': '/root'})
+Environment options -> {}
+Configure file -> {}
+Configure file options -> {}
+Command line arguments -> Namespace(port=None, password=None, motd=None, salt=None, random_salt=False, isolate_rooms=False, disable_chat=False, disable_ready=False, enable_stats=False, enable_tls=False, persistent=False, max_username=None, max_chat_message=None, permanent_rooms=None, listen_ipv4=None, listen_ipv6=None)
+Command line options -> {}
+Bootstrap final options -> {}
 Syncplay startup arguments -> ['--port', '8999', '--salt', '']
-Welcome to Syncplay server, ver. 1.7.0
+Welcome to Syncplay server, ver. 1.7.1
 ```
 
+## Advanced
+
+For some reason, you may need to change the path of the configuration files or working directory. This is possible in the Syncplay container, which requires you to specify it using environment variables.
+
++ `TEMP_DIR` ：Temporary directory, it does not need to be persisted, defaults to `/tmp/`
+
++ `WORK_DIR` ：The working directory, which stores data related to Syncplay, defaults to `/data/`
+
++ `CERT_DIR` ：Certificate directory, which is used to store TLS certificates and private key files, defaults to `/certs/`
+
++ `CONFIG` ：Configuration file, which defines the YAML configuration read by the bootstrap script, defaults to `config.yml`
+
 ## Build Image
 
 You can build an image directly from the source code using the following command.
@@ -248,4 +287,4 @@ docker buildx build -t dnomd343/syncplay                    \
 
 ## License
 
-MIT ©2022 [@dnomd343](https://github.com/dnomd343)
+MIT ©2023 [@dnomd343](https://github.com/dnomd343)