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a1c97f82a6
Add OnRestartFailed to the ready plugin and some various cleanups.
Document slightly better how things are supposed to work with multiple
`ready`'s in the multiple Server Blocks.
All manually tested with this Corefile:
~~~
. {
log
ready
}
example.org {
log
chaos
ready
}
~~~
And then `kill -SIGUSR1` and curling the ready endpoint. This works
well, the FailedReload is triggered by adding a syntax error in the
Corefile.
See #2659
Signed-off-by: Miek Gieben <miek@miek.nl>
59 lines
1.5 KiB
Markdown
59 lines
1.5 KiB
Markdown
# ready
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## Name
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*ready* - enables a readiness check HTTP endpoint.
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## Description
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By enabling *ready* an HTTP endpoint on port 8181 will return 200 OK, when all plugins that are able
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to signal readiness have done so. If some are not ready yet the endpoint will return a 503 with the
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body containing the list of plugins that are not ready. Once a plugin has signaled it is ready it
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will not be queried again.
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Each Server Block that enables the *ready* plugin will have the plugins *in that server block*
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report readiness into the /ready endpoint that runs on the same port. This also means that the
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*same* plugin with different configurations (in potentialy *different* Server Blocks) will have
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their readiness reported as the union of their respective readinesses.
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## Syntax
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~~~
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ready [ADDRESS]
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~~~
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*ready* optionally takes an address; the default is `:8181`. The path is fixed to `/ready`. The
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readiness endpoint returns a 200 response code and the word "OK" when this server is ready. It
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returns a 503 otherwise *and* the list of plugins that are not ready.
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## Plugins
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Any plugin wanting to signal readiness will need to implement the `ready.Readiness` interface by
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implementing a method `Ready() bool` that returns true when the plugin is ready and false otherwise.
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## Examples
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Let *ready* report readiness for both the `.` and `example.org` servers (assuming the *whois*
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plugin also exports readiness):
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~~~ txt
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. {
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ready
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erratic
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}
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example.org {
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ready
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whoami
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}
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~~~
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Run *ready* on a different port.
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~~~ txt
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. {
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ready localhost:8091
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}
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~~~
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