Externally Sourced Configuration File Values外部来源的配置文件值

Use the __rest Expansion Directive使用__rest扩展指令

The __rest expansion directive loads configuration file values from a REST endpoint. __rest扩展指令从REST端点加载配置文件值。__rest supports loading specific values in the configuration file or loading the entire configuration file.__rest支持在配置文件中加载特定值或加载整个配置文件。

storage:
  dbPath: "/var/lib/mongo"
systemLog:
  destination: file
  path: "/var/log/mongodb/mongod.log"
net:
  bindIp: 192.51.100.24,127.0.0.1
  tls:
    mode: requireTLS
    certificateKeyFile: "/etc/tls/mongod.pem"
    certificateKeyFilePassword:
      __rest: "https://myrestserver.example.net/api/config/myCertKeyFilePassword"
      type: "string"

__rest: "https://myrestserver.example.net/api/config/fullConfig"
type: "yaml"

Use the __exec Expansion Directive使用__exec扩展指令

The __exec expansion directive loads configuration file values from a shell or terminal command. __exec扩展指令从shell或终端命令加载配置文件值。__exec supports loading specific values in the configuration file or loading the entire configuration file.__exec支持在配置文件中加载特定值或加载整个配置文件。

storage:
  dbPath: "/var/lib/mongo"
systemLog:
  destination: file
  path: "/var/log/mongodb/mongod.log"
net:
  bindIp: 192.51.100.24,127.0.0.1
  tls:
    mode: requireTLS
    certificateKeyFile: "/etc/tls/mongod.pem"
    certificateKeyFilePassword:
      __exec: "python /home/myUserName/getPEMPassword.py"
      type: "string"

__exec: "python /home/myUserName/getFullConfig.py"
type: "yaml"

Expansion Directives Reference扩展指令参考

__rest

The __rest expansion directive loads configuration file values from a REST endpoint. __rest扩展指令从REST端点加载配置文件值。__rest supports loading specific values in the configuration file or loading the entire configuration file. 支持在配置文件中加载特定值或加载整个配置文件。The mongod/mongos then starts using the externally sourced values as part of its configuration.mongod/mongos然后开始使用外部来源的值作为其配置的一部分。

The __rest expansion directive has the following syntax:__rest扩展指令具有以下语法：

• To specify a REST endpoint for a specific configuration file setting or settings:要为特定配置文件设置指定REST端点，请执行以下操作：

  <some configuration file setting>:
    __rest: "<string>"
    type: "string"
    trim: "none|whitespace"
    digest: "<string>"
    digest_key: "<string>"

• To specify a REST endpoint for the entire configuration file:要为整个配置文件指定REST端点，请执行以下操作：

  __rest: "<string>"
  type: "yaml"
  trim: "none|whitespace"

  If specifying the entire configuration file via REST endpoint, the expansion directive and its options must be the only values specified in the configuration file.如果通过REST端点指定整个配置文件，则扩展指令及其选项必须是配置文件中指定的唯一值。

__rest takes the following fields:采用以下字段：

Field字段	Type类型	Description描述
__rest	string	Required The URL against which the mongod/mongos issues a GET request to retrieve the externally sourced value.mongod/mongos发出GET请求以检索外部来源值的URL。 For non-localhost REST endpoints (e.g. a REST endpoint hosted on a remote server), __rest requires encrypted (https://) URLs where both the host machine and the remote server support TLS 1.1 or later.对于非本地主机REST端点（例如远程服务器上托管的REST端点），__rest需要加密（https://）URL，其中主机和远程服务器都支持TLS 1.1或更高版本。 If the REST endpoint specified in the URL requires authentication, encode credentials into the URL with the standard RFC 3986 User Information format.如果URL中指定的REST端点需要身份验证，请使用标准RFC 3986用户信息格式将凭据编码到URL中。 For localhost REST endpoints (e.g. a REST endpoint listening on the host machine), __rest allows unencrypted (http://) URLs.对于本地主机REST端点（例如，在主机上侦听的REST端点），__rest允许未加密的（http://）URL。 Important重要 The value returned by the specified REST endpoint cannot include any additional expansion directives. 指定的REST端点返回的值不能包含任何其他扩展指令。The mongod/mongos does not perform additional processing on the returned data and will terminate with an error code if the returned data includes additional expansion directives.mongod/mongos不会对返回的数据执行额外的处理，如果返回的数据包含额外的扩展指令，则会以错误代码终止。
type	string	Optional. 可选。Controls how __rest parses the returned value from the specified URL.控制__rest如何解析来自指定URL的返回值。 Possible values are:可能的值包括： string (Default) Directs __rest to parse the returned data as a literal string. 指示__rest将返回的数据解析为文本字符串。If specifying string, the entire __rest block and supporting options must be nested under the field for which you are loading externally sourced values.如果指定字符串，则整个__rest块和支持选项必须嵌套在要为其加载外部源值的字段下。 yaml Directs __rest to parse the returned data as a yaml formatted file. 指示__rest将返回的数据解析为yaml格式的文件。If specifying yaml, the __rest block must be the only content in the configuration file. 如果指定yaml，__rest块必须是配置文件中的唯一内容。The mongod/mongos replaces the configuration file contents with the yaml retrieved from the REST resource.mongod/mongos用从REST资源检索的yaml替换配置文件内容。
trim	string	Optional. 可选。Specify whitespace to direct __rest to trim any leading or trailing whitespace, specifically occurrences of " ", "\r", "\n", "\t", "\v", and "\f". 指定whitespace以指示__rest修剪任何前导或尾随空白，特别是出现" "、"\r"、"\n"、"\t"、"\v"和"\f"。Defaults to none, or no trimming. 默认为none或“无修剪”。
digest	string	Optional. 可选。The SHA-256 digest of the expansion result.扩展结果的SHA-256摘要。 If specified, you must also specify the digest_key.如果指定，还必须指定digest_key。
digest_key	string	Optional. 可选。The hexadecimal string representation of the secret used to calculate the SHA-256 digest.用于计算SHA-256摘要的秘密的十六进制字符串表示。 If specified, you must also specify the digest.如果指定，还必须指定摘要。

Note注意

• If the configuration file includes the __rest expansion, on Linux/macOS, the read access to the configuration file must be limited to the user running the mongod/mongos process only.如果配置文件包含__rest扩展，在Linux/macOS上，对配置文件的读取权限必须仅限于运行mongod/mongos进程的用户。
• To enable parsing of the __rest expansion directive, start the mongod/mongos with the --configExpand "rest" option.要启用__rest扩展指令的解析，请使用--configExpand "rest"选项启动mongod/mongos。

For examples, see Use the __rest Expansion Directive.例如，请参阅使用__rest扩展指令。

__exec

The __exec expansion directive loads configuration file values from the output of a shell or terminal command. __exec扩展指令从shell或终端命令的输出中加载配置文件值。__exec supports loading specific values in the configuration file or loading the entire configuration file. 支持在配置文件中加载特定值或加载整个配置文件。 The mongod/mongos then starts using the externally sourced values as part of its configuration.mongod/mongos然后开始使用外部来源的值作为其配置的一部分。

The __exec expansion directive has the following syntax:__exec扩展指令具有以下语法：

• To specify a shell or terminal command for a specific configuration file setting or settings:要为特定配置文件设置指定shell或终端命令，请执行以下操作：

  <some configuration file setting>:
    __exec: "<string>"
    type: "string"
    trim: "none|whitespace"

• To specify a a shell or terminal command for the entire configuration file:要为整个配置文件指定shell或终端命令，请执行以下操作：

  __exec: "<string>"
  type: "yaml"
  trim: "none|whitespace"

  If specifying the entire configuration file via a terminal or shell command, the expansion directive and its options must be the only values specified in the configuration file.如果通过终端或shell命令指定整个配置文件，则扩展指令及其选项必须是配置文件中指定的唯一值。

__exec takes the following fields:采用以下字段：

Field字段	Type类型	Description描述
__exec	string	Required. 必需。The string which the mongod/mongos executes on the terminal or shell to retrieve the externally sourced value.mongod/mongos在终端或shell上执行以检索外部源值的字符串。 On Linux and OSX hosts, execution is handled via POSIX popen(). 在Linux和OSX主机上，通过POSIX popen()处理执行。On Windows hosts, execution is handled via the process control API. 在Windows主机上，通过进程控制API处理执行。__exec opens a read-only pipe as the same user that started the mongod or mongos.与启动mongod或mongos的同一用户打开只读管道。 Important重要 The data returned by executing the specified command cannot include any additional expansion directives.执行指定命令返回的数据不能包含任何其他扩展指令。 The mongod/mongos does not perform additional processing on the returned data and will terminate with an error code if the returned data includes additional expansion directives.mongod/mongos不会对返回的数据执行额外的处理，如果返回的数据包含额外的扩展指令，则会以错误代码终止。
type	string	Optional. 可选。Controls how __exec parses the value returned by the executed command.控制__exec如何解析执行的命令返回的值。 Possible values are:可能的值包括： string (Default ) Directs __exec to parse the returned data as a literal string. 指示__exec将返回的数据解析为文本字符串。If specifying string, the entire __exec block and supporting options must be nested under the field for which you are loading externally sourced values.如果指定string，则整个__exec块和支持选项必须嵌套在要为其加载外部源值的字段下。 yaml Directs __exec to parse the returned data as a yaml formatted file. 指示__exec将返回的数据解析为yaml格式的文件。If specifying yaml, the __exec block must be the only content in the configuration file. 如果指定yaml，__exec块必须是配置文件中的唯一内容。The mongod/mongos replaces the configuration file contents with the yaml retrieved from the executed command.mongod/mongos用从执行的命令中检索的yaml替换配置文件内容。
trim	string	Optional. 可选。Specify whitespace to direct __exec to trim any leading or trailing whitespace, specifically occurrences of " ", "\r", "\n", "\t", "\v", and "\f". 指定whitespace以指示__exec修剪任何前导或尾随空白，特别是出现" "、"\r"、"\n"、"\t"、"\v"和"\f"。Defaults to none, or no trimming. 指定whitespace以指示__exec修剪任何前导或尾随空白，特别是出现" "、"\r"、"\n"、"\t"、"\v"和"\f"。默认为none或“无修剪”。
digest	string	Optional. 可选。The SHA-256 digest of the expansion result.扩展结果的SHA-256摘要。 If specified, you must also specify the digest_key如果指定，还必须指定digest_key
digest_key	string	Optional. 可选。The hexadecimal string representation of the secret used to calculate the SHA-256 digest.用于计算SHA-256摘要的秘密的十六进制字符串表示。 If specified, you must also specify the digest如果指定，还必须指定摘要

Note注意

• If the configuration file includes the __exec expansion, on Linux/macOS, the write access to the configuration file must be limited to the user running the mongod/mongos process only.如果配置文件包含__exec扩展，则在Linux/macOS上，对配置文件的写入权限必须仅限于运行mongod/mongos进程的用户。
• To enable parsing of the __exec expansion directives, start the mongod/mongos with the --configExpand "exec" option.要启用__exec扩展指令的解析，请使用--configExpand "exec"选项启动mongod/mongos。

For examples, see Use the __exec Expansion Directive.例如，请参阅使用__exec扩展指令。

Output the Configuration File with Resolved Expansion Directive Values使用解析的扩展指令值输出配置文件

You can test the final output of a configuration file that specifies one or more expansion directives by starting the mongod/mongos with the --outputConfig option. 通过使用--outputConfig选项启动mongod/mongos，可以测试指定一个或多个扩展指令的配置文件的最终输出。A mongod/mongos started with --outputConfig outputs the resolved YAML configuration document to stdout and halts. 以--outputConfig开头的mongod/mongos将解析的YAML配置文档输出到stdout并停止。If any expansion directive specified in the configuration file returns additional expansion directives, the mongod/mongos throws an error and terminates.如果配置文件中指定的任何扩展指令返回其他扩展指令，mongod/mongos将抛出错误并终止。

For example, the following configuration file mongod.conf contains a __rest expansion directive:例如，以下配置文件mongod.conf包含__rest扩展指令：

storage:
  dbPath: "/var/lib/mongo"
systemLog:
  destination: file
  path: "/var/log/mongodb/mongod.log"
net:
  port:
    __rest: "https://mongoconf.example.net:8080/record/1"
    type: string

The string recorded at the specified URL is 20128记录在指定URL的字符串为20128

If the configuration file includes the __rest expansion, on Linux/macOS, the read access to the configuration file must be limited to the user running the mongod/mongos process only.如果配置文件包含__rest扩展，在Linux/macOS上，对配置文件的读取权限必须仅限于运行mongod/mongos进程的用户。

Start the mongod with the --configExpand "rest" and --outputConfig options:使用--configExpand "rest"和--outputConfig选项启动mongod：

mongod -f mongod.conf --configExpand rest --outputConfig

The mongod outputs the following to stdout before terminating:mongod在终止前向stdout输出以下内容：

config: mongod.conf
storage:
  dbPath: "/var/lib/mongo"
systemLog:
  destination: file
  path: "/var/log/mongodb/mongod.log"
net:
  port: 20128
outputConfig: true