b56b080a7c
* introduce new interface "dnsserver.Viewer", that allows a plugin implementing it to decide if a query should be routed into its server block. * add new plugin "view", that uses the new interface to enable a user to define expression based conditions that must be met for a query to be routed to its server block. Signed-off-by: Chris O'Haver <cohaver@infoblox.com>
48 lines
1.3 KiB
Go
48 lines
1.3 KiB
Go
package view
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import (
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"context"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/pkg/expression"
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"github.com/coredns/coredns/request"
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"github.com/antonmedv/expr"
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"github.com/antonmedv/expr/vm"
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"github.com/miekg/dns"
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)
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// View is a plugin that enables configuring expression based advanced routing
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type View struct {
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progs []*vm.Program
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viewName string
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Next plugin.Handler
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}
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// Filter implements dnsserver.Viewer. It returns true if all View rules evaluate to true for the given state.
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func (v *View) Filter(ctx context.Context, state *request.Request) bool {
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env := expression.DefaultEnv(ctx, state)
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for _, prog := range v.progs {
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result, err := expr.Run(prog, env)
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if err != nil {
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return false
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}
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if b, ok := result.(bool); ok && b {
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continue
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}
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// anything other than a boolean true result is considered false
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return false
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}
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return true
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}
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// ViewName implements dnsserver.Viewer. It returns the view name
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func (v *View) ViewName() string { return v.viewName }
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// Name implements the Handler interface
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func (*View) Name() string { return "view" }
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// ServeDNS implements the Handler interface.
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func (v *View) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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return plugin.NextOrFailure(v.Name(), v.Next, ctx, w, r)
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}
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