mirror of
https://github.com/coredns/coredns.io.git
synced 2024-04-21 12:32:00 +00:00
Felix IngramandMiek Gieben
878d6e9e4e
The docs for this in Caddy seem to be at https://caddyserver.com/docs/on (though this is for http.on, so forgive me if it's not the right link)
67 lines
2.1 KiB
Markdown
67 lines
2.1 KiB
Markdown
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title = "on"
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description = "*on* - executes a command when a specified event is triggered."
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weight = 10
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tags = [ "plugin" , "on" ]
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categories = [ "plugin", "external" ]
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date = "2018-01-22T07:53:19+01:00"
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repo = "https://github.com/mholt/caddy"
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home = "https://caddyserver.com/docs/on"
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default = "yes"
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## Description
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*on* executes a command when a specified event is triggered. This can be useful for preparing to
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serve a site by running a script or starting a background process when the server starts, or for
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stopping it when the server exits.
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Each command that is executed is blocking, unless you suffix the command with a space and &, which
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will cause the command to be run in the background. (Do not do this when the server is exiting, or
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the command may not finish before its parent process exits.) The output and error of the command go
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to standard output and standard error, respectively. There is no standard input.
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A command will only be executed once for each time it appears in the Corefile. In other words, even
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if this directive is shared by more than one zone, a command will only execute once per appearance
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in the Corefile.
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Note that commands scheduled for the shutdown event will not execute if CoreDNS is force-terminated,
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for example, by using a "Force Quit" feature provided by your operating system. However, a typical
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SIGINT (Ctrl+C) will allow the shutdown commands to execute.
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## Syntax
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~~~
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on EVENT COMMAND
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~~~
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**EVENT** is the name of the *event* on which to execute the **COMMAND** (see list below).
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**COMMAND** is the command to execute; it may be followed by arguments.
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### Events
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Commands can execute on the following events:
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* `startup` - The server instance is starting or starting up
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* `shutdown` - The server instance is shutting down (not restarting)
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## Examples
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Start php-fpm before the server starts listening:
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~~~
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on startup /etc/init.d/php-fpm start
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~~~
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Stop php-fpm when the server quits:
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~~~
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on shutdown /etc/init.d/php-fpm stop
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~~~
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On Windows, you might need to use quotes when the command path contains spaces:
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~~~
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on startup "\"C:\Program Files\PHP\v7.0\php-cgi.exe\" -b 127.0.0.1:9123" &
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~~~
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