TrueCloudLab/coredns
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Follow up on #1867 : use one map in backend_lookup (#1869)

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Reduce map usage and combine two maps into one; add isDuplicate that
tests and adds to make things more readable.
This commit is contained in:
Miek Gieben 2018-06-18 11:16:56 +01:00 • committed by GitHub
parent 6fbc1f8990
commit ab9efdcac4
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GPG key ID: 4AEE18F83AFDEB23
1 changed files with 33 additions and 32 deletions
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65
plugin/backend_lookup.go
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@ -156,16 +156,8 @@ func SRV(b ServiceBackend, zone string, state request.Request, opt Options) (rec
return nil, nil, err
}
type s struct {
n string
p uint16
}
dup := make(map[s]bool)
type a struct {
n string
a string
}
dupAddr := make(map[a]bool)
dup := make(map[item]bool)
lookup := make(map[string]bool)
// Looping twice to get the right weight vs priority. This might break because we may drop duplicate SRV records latter on.
w := make(map[int]int)
@ -180,7 +172,6 @@ func SRV(b ServiceBackend, zone string, state request.Request, opt Options) (rec
}
w[serv.Priority] += weight
}
lookup := make(map[string]bool)
for _, serv := range services {
w1 := 100.0 / float64(w[serv.Priority])
if serv.Weight == 0 {
@ -227,20 +218,18 @@ func SRV(b ServiceBackend, zone string, state request.Request, opt Options) (rec
if e1 == nil {
extra = append(extra, addr...)
}
// IPv6 lookups here as well? AAAA(zone, state1, nil).
// TODO(miek): AAAA as well here.
case dns.TypeA, dns.TypeAAAA:
addr := serv.Host
serv.Host = msg.Domain(serv.Key)
srv := serv.NewSRV(state.QName(), weight)
if _, ok := dup[s{srv.Target, srv.Port}]; !ok {
dup[s{srv.Target, srv.Port}] = true
if ok := isDuplicate(dup, srv.Target, "", srv.Port); !ok {
records = append(records, srv)
}
if _, ok := dupAddr[a{srv.Target, addr}]; !ok {
dupAddr[a{srv.Target, addr}] = true
if ok := isDuplicate(dup, srv.Target, addr, 0); !ok {
extra = append(extra, newAddress(serv, srv.Target, ip, what))
}
}
@ -255,17 +244,7 @@ func MX(b ServiceBackend, zone string, state request.Request, opt Options) (reco
return nil, nil, err
}
type s struct {
n string
p uint16
}
dup := make(map[s]bool)
type a struct {
n string
a string
}
dupAddr := make(map[a]bool)
dup := make(map[item]bool)
lookup := make(map[string]bool)
for _, serv := range services {
if !serv.Mail {
@ -305,20 +284,18 @@ func MX(b ServiceBackend, zone string, state request.Request, opt Options) (reco
if e1 == nil {
extra = append(extra, addr...)
}
// e.AAAA as well
// TODO(miek): AAAA as well here.
case dns.TypeA, dns.TypeAAAA:
addr := serv.Host
serv.Host = msg.Domain(serv.Key)
mx := serv.NewMX(state.QName())
if _, ok := dup[s{mx.Mx, mx.Preference}]; !ok {
dup[s{mx.Mx, mx.Preference}] = true
if ok := isDuplicate(dup, mx.Mx, "", mx.Preference); !ok {
records = append(records, mx)
}
// Fake port to be 0 for address...
if _, ok := dupAddr[a{serv.Host, addr}]; !ok {
dupAddr[a{serv.Host, addr}] = true
if ok := isDuplicate(dup, serv.Host, addr, 0); !ok {
extra = append(extra, newAddress(serv, serv.Host, ip, what))
}
}
@ -477,4 +454,28 @@ func checkForApex(b ServiceBackend, zone string, state request.Request, opt Opti
return b.Services(state, false, opt)
}
// item holds records.
type item struct {
name string // name of the record (either owner or something else unique).
port uint16 // port of the record (used for address records, A and AAAA).
addr string // address of the record (A and AAAA).
}
// isDuplicate uses m to see if the combo (name, addr, port) already exists. If it does
// not exist already IsDuplicate will also add the record to the map.
func isDuplicate(m map[item]bool, name, addr string, port uint16) bool {
if addr != "" {
_, ok := m[item{name, 0, addr}]
if !ok {
m[item{name, 0, addr}] = true
}
return ok
}
_, ok := m[item{name, port, ""}]
if !ok {
m[item{name, port, ""}] = true
}
return ok
}
const hostmaster = "hostmaster"