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plugin/view: Advanced routing interface and new 'view' plugin (#5538)

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* 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>
This commit is contained in:
Chris O'Haver
2022-09-08 14:56:27 -04:00
committed by GitHub
parent 1f0a41a665
commit b56b080a7c
36 changed files with 880 additions and 114 deletions
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38
core/dnsserver/register.go
View File

@@ -138,13 +138,6 @@ func (h *dnsContext) InspectServerBlocks(sourceFile string, serverBlocks []caddy
// MakeServers uses the newly-created siteConfigs to create and return a list of server instances.
func (h *dnsContext) MakeServers() ([]caddy.Server, error) {
// Now that all Keys and Directives are parsed and initialized
// lets verify that there is no overlap on the zones and addresses to listen for
errValid := h.validateZonesAndListeningAddresses()
if errValid != nil {
return nil, errValid
}
// Copy the Plugin, ListenHosts and Debug from first config in the block
// to all other config in the same block . Doing this results in zones
// sharing the same plugin instances and settings as other zones in
@@ -198,6 +191,27 @@ func (h *dnsContext) MakeServers() ([]caddy.Server, error) {
}
}
// For each server config, check for View Filter plugins
for _, c := range h.configs {
// Add filters in the plugin.cfg order for consistent filter func evaluation order.
for _, d := range Directives {
if vf, ok := c.registry[d].(Viewer); ok {
if c.ViewName != "" {
return nil, fmt.Errorf("multiple views defined in server block")
}
c.ViewName = vf.ViewName()
c.FilterFuncs = append(c.FilterFuncs, vf.Filter)
}
}
}
// Verify that there is no overlap on the zones and listen addresses
// for unfiltered server configs
errValid := h.validateZonesAndListeningAddresses()
if errValid != nil {
return nil, errValid
}
return servers, nil
}
@@ -253,7 +267,15 @@ func (h *dnsContext) validateZonesAndListeningAddresses() error {
for _, h := range conf.ListenHosts {
// Validate the overlapping of ZoneAddr
akey := zoneAddr{Transport: conf.Transport, Zone: conf.Zone, Address: h, Port: conf.Port}
existZone, overlapZone := checker.registerAndCheck(akey)
var existZone, overlapZone *zoneAddr
if len(conf.FilterFuncs) > 0 {
// This config has filters. Check for overlap with other (unfiltered) configs.
existZone, overlapZone = checker.check(akey)
} else {
// This config has no filters. Check for overlap with other (unfiltered) configs,
// and register the zone to prevent subsequent zones from overlapping with it.
existZone, overlapZone = checker.registerAndCheck(akey)
}
if existZone != nil {
return fmt.Errorf("cannot serve %s - it is already defined", akey.String())
}