crtmpserver配置文件详解

Configuration file
配置文件

The configuration file is actually a lua script which must contain an object called configuration. 
This will be read by the server and used to fully configure the server. Besides this object called 
configuration you can have functions, include other lua libraries, etc. In the end, you have to
make the configuration object available. The rest of this section will explain the structue of 
configuration object in great detail. But first, let's take an bird-eye view.

配置文件实际上是一个Lua脚本，它包含至少一个configuration的对象，
从而为程序提供灵活的扩展和定制功能。
除了configuration对象外，还可以有函数，Lua库等。

Main structure
主结构

configuration=
{
  daemon=false,
  pathSeparator="/",
  logAppenders=
  {
    -- content removed for clarity
  },
  applications=
  {
    -- content removed for clarity
  }
}

configuration structure
key	type	mandatory	description
daemon	boolean	yes	true means the server will start in daemon mode.  false means it will start in console mode (nice for development) true  表示 服务以后台方式启动; false 表示 服务以控制台模式启动(以用于开发);
pathSeparator	string(1)	yes	This value will be used by the server to compose paths (like media files paths). Examples: on UNIX-like systems this is / while on windows is \. Special care must be taken when you specify this values on windows because \ is an escape sequence for lua so the value should be “\\” 用来分隔路径;  例如，在UNIX-like是 /, Windows是 \  ;
logAppenders	object	yes	Will hold a collection of log appenders. Each of log messages will pass through all the log appenders enumerated here. More details below 配置日志追加的容器
applications	object	yes	Will hold a collection of loaded applications. Besides that, it will also hold few other values. More detailsbelow 配置加载各种应用的容器

When the server starts, the following sequence of operations is performed:
服务启动时，将按顺序执行下列操作:

1. The configuration file is loaded. Part of the loading process, is the verification.
   If something is wrong with the syntax please read 
2. daemon value is read. The server now will either fork to become daemon
   or continue as is in console mode
   读取 daemon 值，判断服务是以后台方式启动还是以控制台方式启动
3. logAppenders is read. This is where all log appenders are configured and brought up to running state.
   Depending on the collection of your log appenders, you may (not) see further log messages
   读取日志追加器，用来配置日志记录并启动到运行状态，
   依据日志追加器，可以看到更多的日志信息
4. applications is taken into consideration. Up until now, the server doesn't do much.
   After this stage completes, all the applications are fully functional and the server is online and ready to do stuff
   最后的应用加载，只到这一步完成后，服务和应用才在线，并准备就绪。

日志追加器
logAppenders

This section contains a list of log appenders. The entire collection of appenders listed in this section
is loaded inside the logger at config-time. All log messages will be than passed to all this log appenders.
Depending on the log level, an appender may (not) log the message. “Logging” a message means “saving”
it on the specified “media” (in the example below we have a console appender and a file).
这部分包含了一个日志追加器的列表。
整个日志追加器的添加是在加载时配置，
依据日志级别，追加器可以选择是否有日志消息输出到指定目的处；
logAppenders=
{
  {
    name="console appender",
    type="coloredConsole",
    level=6
  },
  {
    name="file appender",
    type="file",
    level=6,
    fileName="/tmp/crtmpserver.log"
  }
},

logAppenders structure
key	type	mandatory	description
name	string	yes	The name of the appender. Is usually used inside pretty print routines 追加器的名字.
type	string	yes	The type of the appender. It can be console, coloredConsole or file. console and  coloredConsole will output to console. The difference between them is that coloredConsole  will also apply a color to the message, depending on the log level. Quite useful when eye-balling the console.  file log appender will output everything on the specified file 追加器的类型 可以是控制台，带颜色控制台或文件； 控制台和带颜色控制台 都会将日志消息输出到控制台， 不同之处在于带颜色控制台会依据日志级别进行颜色标记； 文件类型则会将所有消息输出到指定的文件；
level	number	yes	The log level used. The values are presented just below. Any message having having a log level less or equal to this value will be logged. The rest are discarded. Example: setting level to 0, will only log FATAL errors. Setting it to 3, will only log FATAL, ERROR, WARNING and INFO 日志的级别 可见下表中的级别定义； 只有小于或等于这个级别的日志消息会被记录，高于这个级别则都被丢弃； 例如:   级别为0时，只记录 FATAL 消息；   级别为3时，只记录 FATAL, ERROR, WARNING, INFO 消息；
fileName	string	yes	If the type of appender is a file, this will contain the path of the file 如果追加器类型为文件，则在此处指定日志文件和路径

Log levels
Name	Value
0	FATAL
1	ERROR
2	WARNING
3	INFO
4	DEBUG
5	FINE
6	FINEST

Observation: When daemon mode is set to true, all console appenders will be ignored.
(Read the explanation for daemon setting here)
注意:
当使用后台模式时，所有的控制台追加消息将会被忽略。

应用
applications

This section is where all the applications inside the server are placed.
It holds the attributes of each application that the server will use to launch them.
Each application may have specific attributes that it requires to execute its own functionality.
这部分用来配置各种应用，并设置这些应用的属性；
每个应用的属性都对应了这个应用的指定功能；
applications=
{
  rootDirectory="applications",
  {
    -- settings for application 1
    -- content removed for clarity
  },
  {
    -- settings for application 2
    -- content removed for clarity
  },
  {
    -- settings for application 3
    -- content removed for clarity
  }
}

applications structure
key	type	mandatory	description
rootDirectory	string	true	The folder containing applications subfolders. If this path begins with a / or \ (depending on the OS), than is treated as an absolute path. Otherwise is treated as a path relative to the run-time directory (the place where you started the server) 这个目录包含了应用的子目录； 如果路径以 / 或 \ 开始， 则视其为绝对路径，否则视为启动服务时所在的相对路径；

Following the rootDirectory, there is a collection of applications. Each application has
its properties contained in an object. See details below
rootDirectory 之后，是应用的集合；每个应用都定义了一个有特定属性的对象；
细节如下所示；

应用定义
application definition

This is where the settings of an application are defined. We will present only the
settings common to all applications. Later on, we will also explain the settings particular to certain
applications Since revision 790 there is a new cool feature: mediaStorage; with this feature
basicaly an application may have multiple mediaFolder's and .seek/.meta files are now stored into
separate folder from media file that are streamed.
这些目录用来定义应用.
自从790版本后，添加了一新的功能：mediaStorage; 
这个功能能使应用可以有多个mediaFolder，
并且可以将.seek/.meta文件和媒体文件分开存储在不同的文件夹中；


{
  name="flvplayback",
  protocol="dynamiclinklibrary",
  description="FLV Playback Sample",
  default=false,
  validateHandshake=true,
  enableCheckBandwidth=true,
  -- this settings are now part of mediaStorage setting
  -- keyframeSeek=true,
  -- seekGranularity=1.5,
  -- clientSideBuffer=12,
  -- generateMetaFiles=true,
  -- renameBadFiles=true,
  aliases=
  {
    "simpleLive",
    "vod",
    "live",
    "WeeklyQuest",
    "SOSample",
    "oflaDemo",
    "chat",
  },
  acceptors = 
  {
    {
      -- acceptor 1
      -- content removed for clarity
    },
    {
      -- acceptor 2
      -- content removed for clarity
    },
    {
      -- acceptor n
      -- content removed for clarity
    },
  },
  -- new feature mediaStorage
  mediaStorage = {
     namedStorage1={
      description="Main storage",
      mediaFolder="/usr/main_storage/media", -- only this parameter IS MANDATORY
      metaFolder="/usr/main_storage/metadata", -- if you have static large file to stream it is good to know that for a file around 500MB 
                                               -- it's .seek file has around 16MB; so it would be preffer to designate metafolder into a system
                                               -- partition which has enough space... for no surprises... :)
      statsFolder="/usr/main_storage/statsFolder",
      enableStats=true,
      clientSideBuffer=16,
      keyframeSeek=false, -- should crtmpdserver DO SEEK ONLY IN key-frame (true/false)? 
                          -- very useful to know in situations like play/pause/resume (meaning pause/seek/play)
      seekGranularity=1,
      generateMetaFiles=false,
      renameBadFiles=false,
    },
    --[[{
      -- here is another example of storage; it does not start with name={...}
       description="Second storage of same application",
       mediaFolder="/usr/second_storage/media/flv",
       metaFolder="/usr/second_storage/metadata",
       statsFolder="/usr/second_storage/statsFolder",
    },]]--
  }, 
  externalStreams = 
  {
    {
      -- stream 1
      -- content removed for clarity
    },
    {
      -- stream 2
      -- content removed for clarity
    },
    {
      -- stream n
      -- content removed for clarity
    },
  },
  authentication=
  {
    -- content removed for clarity
  }
}

application structure
key	type	mandatory	description
name	string	yes	Name of application. 应用的名称
protocol	string	yes	Type of application. The value dynamiclinklibrary means the application is a shared library. 应用的类型 值为 dynamiclinklibrary 意即 应用是一个共享库
description	string	no	You can put a description of the application here. 应用的描述信息
default	boolean	no	This flag designates the default application. The default application is responsible in analyzing the connectrequest and distribute the future connection to the correct application. 这个标志指定了默认应用； 默认应用负责分析连接请求并将连接分配到正确的应用
validateHandshake	boolean	no	Tells the server to validate the client's handshake before going further. This is optional with a default value of true. If this is true and the handshake fails, the connection is dropped. If this is false, handshake validation will not be enforced and all the connections are accepted no matter if they are correctly hand shaking or not. 通知服务器在进行下一步前要对客户端的握手进行验证； 这是一个可选项，其默认值为真。 如果这个值为真 且 握手失败，服务器就放弃这个连接。 如果这个值为假，则不会进行强制的握手验证，所有的连接都会被接受；
keyframeSeek	boolean	no	This instructs the streamer to seek only on key frames. In case of live streaming, this is discarded. 这个属性指定了流生成器只在关键帧搜索， 如果是直播流，则忽略这个值
seekGranularity	double	no	The seek resolution/granularity value in seconds. Values are between 0.1 and 600. For example, if granularity is 10 seconds, and a seek to t=2:34 is desired, the seek will actually go to t=2:30.  60seconds is recommended for full length movies and 1 second for video clips. 搜索的精细度，以秒为单位, 值域定义在 0.1 ~ 600;  例如： 如果粒度定义为10秒，并期望定位到 t= 2:34;  则实际上是会定位到 t= 2:30.  60秒被认定为完整的电影长度，1秒为电影片断；
clientSideBuffer	double	no	The amount of client side buffer that will be maintained for each connection. Values are between 5 and30 seconds. 每个连接在客户端的缓冲秒数，值定义在5 ~ 30 秒；
generateMetaFiles	boolean	no	This will generate seek/meta files on application startup. 在应用启动前生成 seek/meta文件
renameBadFiles	boolean	no	If this flag is true and the media file can't be parsed, the media file will be renamed to *.bad. Otherwise it will be left alone. 如果这上值为真且媒体文件是不能被解析的，则媒体文件被重命名为 *.bad， 否则这样的文件将不做处理
aliases	object	no	The application will also be known by this name. 应用的别名
acceptors	object	no	Acceptors hold the service that will be hosted to the server. An application can have its own acceptor, but this is not entirely required, and can be optional. 接受器保持这个服务并让服务器托管； 应用可以有它自己的接受器，但这个是可选的；
externalStreams	object	no
authentication	object	no
mediaFolder	string	yes	When define mediaStorage this field is mandatory as it points out physical location of media files. 当定义了 mediaStorage时，这个域用来指定媒体文件的物理位置；
metaFolder	string	no	It holds the location where .seek/.meta files created from files inside mediaFolder are stored. 指定用来存放 .seek/.meta文件的位置；
statsFolder	string	no	Location for stats files. 服状态文件的位置

acceptor structure
key	type	mandatory	description
ip	string	yes	The IP where the service is located. 0.0.0.0 means all interfaces and all IPs. 服务所在的IP, 0.0.0.0表示所有接口和所有IP;
port	string	yes	Port number that the service will listen to. 服务监听的端口号
protocol	string	yes	The protocol stack handled by the ip:port combination. 对应 ip:port的服务的协议