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agent: First pass supporting DNS TTLs

This commit is contained in:
Armon Dadgar 2014-06-08 16:01:06 -07:00
parent dea2eba631
commit ba4c40531d
1 changed files with 23 additions and 12 deletions
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35
command/agent/dns.go
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@ -334,14 +334,15 @@ RPC:
}
// Add the node record
records := d.formatNodeRecord(&out.NodeServices.Node, req.Question[0].Name, qType)
records := d.formatNodeRecord(&out.NodeServices.Node, req.Question[0].Name,
qType, d.config.NodeTTL)
if records != nil {
resp.Answer = append(resp.Answer, records...)
}
}
// formatNodeRecord takes a Node and returns an A, AAAA, or CNAME record
func (d *DNSServer) formatNodeRecord(node *structs.Node, qName string, qType uint16) (records []dns.RR) {
func (d *DNSServer) formatNodeRecord(node *structs.Node, qName string, qType uint16, ttl time.Duration) (records []dns.RR) {
// Parse the IP
ip := net.ParseIP(node.Address)
var ipv4 net.IP
@ -355,7 +356,7 @@ func (d *DNSServer) formatNodeRecord(node *structs.Node, qName string, qType uin
Name: qName,
Rrtype: dns.TypeA,
Class: dns.ClassINET,
Ttl: 0,
Ttl: uint32(ttl / time.Second),
},
A: ip,
}}
@ -366,7 +367,7 @@ func (d *DNSServer) formatNodeRecord(node *structs.Node, qName string, qType uin
Name: qName,
Rrtype: dns.TypeAAAA,
Class: dns.ClassINET,
Ttl: 0,
Ttl: uint32(ttl / time.Second),
},
AAAA: ip,
}}
@ -379,7 +380,7 @@ func (d *DNSServer) formatNodeRecord(node *structs.Node, qName string, qType uin
Name: qName,
Rrtype: dns.TypeCNAME,
Class: dns.ClassINET,
Ttl: 0,
Ttl: uint32(ttl / time.Second),
},
Target: dns.Fqdn(node.Address),
}
@ -436,6 +437,16 @@ RPC:
return
}
// Determine the TTL
var ttl time.Duration
if d.config.ServiceTTL != nil {
var ok bool
ttl, ok = d.config.ServiceTTL[service]
if !ok {
ttl = d.config.ServiceTTL["*"]
}
}
// Filter out any service nodes due to health checks
out.Nodes = d.filterServiceNodes(out.Nodes)
@ -449,10 +460,10 @@ RPC:
// Add various responses depending on the request
qType := req.Question[0].Qtype
d.serviceNodeRecords(out.Nodes, req, resp)
d.serviceNodeRecords(out.Nodes, req, resp, ttl)
if qType == dns.TypeSRV {
d.serviceSRVRecords(datacenter, out.Nodes, req, resp)
d.serviceSRVRecords(datacenter, out.Nodes, req, resp, ttl)
}
}
@ -484,7 +495,7 @@ func shuffleServiceNodes(nodes structs.CheckServiceNodes) {
}
// serviceNodeRecords is used to add the node records for a service lookup
func (d *DNSServer) serviceNodeRecords(nodes structs.CheckServiceNodes, req, resp *dns.Msg) {
func (d *DNSServer) serviceNodeRecords(nodes structs.CheckServiceNodes, req, resp *dns.Msg, ttl time.Duration) {
qName := req.Question[0].Name
qType := req.Question[0].Qtype
handled := make(map[string]struct{})
@ -498,7 +509,7 @@ func (d *DNSServer) serviceNodeRecords(nodes structs.CheckServiceNodes, req, res
handled[addr] = struct{}{}
// Add the node record
records := d.formatNodeRecord(&node.Node, qName, qType)
records := d.formatNodeRecord(&node.Node, qName, qType, ttl)
if records != nil {
resp.Answer = append(resp.Answer, records...)
}
@ -506,7 +517,7 @@ func (d *DNSServer) serviceNodeRecords(nodes structs.CheckServiceNodes, req, res
}
// serviceARecords is used to add the SRV records for a service lookup
func (d *DNSServer) serviceSRVRecords(dc string, nodes structs.CheckServiceNodes, req, resp *dns.Msg) {
func (d *DNSServer) serviceSRVRecords(dc string, nodes structs.CheckServiceNodes, req, resp *dns.Msg, ttl time.Duration) {
handled := make(map[string]struct{})
for _, node := range nodes {
// Avoid duplicate entries, possible if a node has
@ -523,7 +534,7 @@ func (d *DNSServer) serviceSRVRecords(dc string, nodes structs.CheckServiceNodes
Name: req.Question[0].Name,
Rrtype: dns.TypeSRV,
Class: dns.ClassINET,
Ttl: 0,
Ttl: uint32(ttl / time.Second),
},
Priority: 1,
Weight: 1,
@ -533,7 +544,7 @@ func (d *DNSServer) serviceSRVRecords(dc string, nodes structs.CheckServiceNodes
resp.Answer = append(resp.Answer, srvRec)
// Add the extra record
records := d.formatNodeRecord(&node.Node, srvRec.Target, dns.TypeANY)
records := d.formatNodeRecord(&node.Node, srvRec.Target, dns.TypeANY, ttl)
if records != nil {
resp.Extra = append(resp.Extra, records...)
}