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8f9f2cd1ab
This middleware acts in the same way as SkyDNS. We might add options
to allow it to be behave different, but for now it will suffice.
A Corefile like:
.:1053 {
etcd miek.nl
proxy . 8.8.8.8:53
}
will perform lookup in etcd and proxy everything not miek.nl to Google
for further resolution.
The internal etcd forwarding *also* uses the proxy infrastructure,
meaning you get health check and such for (almost) free
93 lines
3.0 KiB
Go
93 lines
3.0 KiB
Go
package core
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import (
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"github.com/miekg/coredns/core/https"
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"github.com/miekg/coredns/core/parse"
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"github.com/miekg/coredns/core/setup"
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"github.com/miekg/coredns/middleware"
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)
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func init() {
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// The parse package must know which directives
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// are valid, but it must not import the setup
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// or config package. To solve this problem, we
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// fill up this map in our init function here.
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// The parse package does not need to know the
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// ordering of the directives.
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for _, dir := range directiveOrder {
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parse.ValidDirectives[dir.name] = struct{}{}
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}
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}
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// Directives are registered in the order they should be
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// executed. Middleware (directives that inject a handler)
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// are executed in the order A-B-C-*-C-B-A, assuming
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// they all call the Next handler in the chain.
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//
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// Ordering is VERY important. Every middleware will
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// feel the effects of all other middleware below
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// (after) them during a request, but they must not
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// care what middleware above them are doing.
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//
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// For example, log needs to know the status code and
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// exactly how many bytes were written to the client,
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// which every other middleware can affect, so it gets
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// registered first. The errors middleware does not
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// care if gzip or log modifies its response, so it
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// gets registered below them. Gzip, on the other hand,
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// DOES care what errors does to the response since it
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// must compress every output to the client, even error
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// pages, so it must be registered before the errors
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// middleware and any others that would write to the
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// response.
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var directiveOrder = []directive{
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// Essential directives that initialize vital configuration settings
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{"root", setup.Root},
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{"bind", setup.BindHost},
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{"tls", https.Setup},
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// Other directives that don't create HTTP handlers
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{"startup", setup.Startup},
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{"shutdown", setup.Shutdown},
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// Directives that inject handlers (middleware)
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{"prometheus", setup.Prometheus},
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{"rewrite", setup.Rewrite},
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{"log", setup.Log},
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{"errors", setup.Errors},
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{"etcd", setup.Etcd},
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{"file", setup.File},
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{"reflect", setup.Reflect},
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{"proxy", setup.Proxy},
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}
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// RegisterDirective adds the given directive to caddy's list of directives.
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// Pass the name of a directive you want it to be placed after,
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// otherwise it will be placed at the bottom of the stack.
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func RegisterDirective(name string, setup SetupFunc, after string) {
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dir := directive{name: name, setup: setup}
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idx := len(directiveOrder)
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for i := range directiveOrder {
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if directiveOrder[i].name == after {
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idx = i + 1
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break
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}
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}
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newDirectives := append(directiveOrder[:idx], append([]directive{dir}, directiveOrder[idx:]...)...)
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directiveOrder = newDirectives
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parse.ValidDirectives[name] = struct{}{}
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}
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// directive ties together a directive name with its setup function.
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type directive struct {
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name string
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setup SetupFunc
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}
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// SetupFunc takes a controller and may optionally return a middleware.
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// If the resulting middleware is not nil, it will be chained into
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// the HTTP handlers in the order specified in this package.
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type SetupFunc func(c *setup.Controller) (middleware.Middleware, error)
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