47 lines
1.6 KiB
Go
47 lines
1.6 KiB
Go
package example
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import (
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/metrics"
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"github.com/mholt/caddy"
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)
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// init registers this plugin within the Caddy plugin framework. It uses "example" as the
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// name, and couples it to the Action "setup".
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func init() {
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caddy.RegisterPlugin("example", caddy.Plugin{
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ServerType: "dns",
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Action: setup,
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})
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}
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// setup is the function that gets called when the config parser see the token "example". Setup is responsible
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// for parsing any extra options the example plugin may have. The first token this function sees is "example".
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func setup(c *caddy.Controller) error {
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c.Next() // Ignore "example" and give us the next token.
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if c.NextArg() {
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// If there was another token, return an error, because we don't have any configuration.
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// Any errors returned from this setup function should be wrapped with plugin.Error, so we
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// can present a slightly nicer error message to the user.
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return plugin.Error("example", c.ArgErr())
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}
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// Add a startup function that will -- after all plugins have been loaded -- check if the
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// prometheus plugin has been used - if so we will export metrics. We can only register
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// this metric once, hence the "once.Do".
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c.OnStartup(func() error {
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once.Do(func() { metrics.MustRegister(c, requestCount) })
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return nil
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})
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// Add the Plugin to CoreDNS, so Servers can use it in their plugin chain.
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dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
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return Example{Next: next}
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})
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// All OK, return a nil error.
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return nil
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}
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