ea77f2a2ca
* core: replace GetMiddleware See the discussion in #881. GetMiddleware would add a `nil` middleware to the callstack thereby breaking functionality. This PR drops it in favor of RegisterHandler which is a completely standalone registry for middleware that want to let it self know to other middleware. Currenly *autopath* uses this to call *kubernetes*'s AutoPath method for dynamic autopathing. * Drop GetMiddleware * Register metrics * drop the panic
90 lines
2.1 KiB
Go
90 lines
2.1 KiB
Go
package autopath
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import (
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"fmt"
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/middleware"
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"github.com/coredns/coredns/middleware/kubernetes"
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"github.com/mholt/caddy"
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"github.com/miekg/dns"
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)
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func init() {
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caddy.RegisterPlugin("autopath", 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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func setup(c *caddy.Controller) error {
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ap, mw, err := autoPathParse(c)
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if err != nil {
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return middleware.Error("autopath", err)
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}
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// Do this in OnStartup, so all middleware has been initialized.
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c.OnStartup(func() error {
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// TODO(miek): fabricate test to proof this is not thread safe.
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m := dnsserver.GetConfig(c).GetHandler(mw)
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if m == nil {
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return nil
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}
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if k, ok := m.(kubernetes.Kubernetes); ok {
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ap.searchFunc = k.AutoPath
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}
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return nil
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})
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dnsserver.GetConfig(c).AddMiddleware(func(next middleware.Handler) middleware.Handler {
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ap.Next = next
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return ap
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})
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return nil
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}
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// allowedMiddleware has a list of middleware that can be used by autopath. For this to work, they
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// need to register themselves with dnsserver.RegisterHandler.
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var allowedMiddleware = map[string]bool{
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"@kubernetes": true,
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}
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func autoPathParse(c *caddy.Controller) (*AutoPath, string, error) {
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ap := &AutoPath{}
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mw := ""
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for c.Next() {
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zoneAndresolv := c.RemainingArgs()
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if len(zoneAndresolv) < 1 {
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return ap, "", fmt.Errorf("no resolv-conf specified")
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}
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resolv := zoneAndresolv[len(zoneAndresolv)-1]
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if resolv[0] == '@' {
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_, ok := allowedMiddleware[resolv]
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if ok {
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mw = resolv[1:]
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}
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} else {
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// assume file on disk
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rc, err := dns.ClientConfigFromFile(resolv)
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if err != nil {
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return ap, "", fmt.Errorf("failed to parse %q: %v", resolv, err)
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}
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ap.search = rc.Search
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middleware.Zones(ap.search).Normalize()
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ap.search = append(ap.search, "") // sentinal value as demanded.
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}
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ap.Zones = zoneAndresolv[:len(zoneAndresolv)-1]
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if len(ap.Zones) == 0 {
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ap.Zones = make([]string, len(c.ServerBlockKeys))
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copy(ap.Zones, c.ServerBlockKeys)
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}
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for i, str := range ap.Zones {
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ap.Zones[i] = middleware.Host(str).Normalize()
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}
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}
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return ap, mw, nil
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}
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