func (s *HTTPServer) HealthServiceNodes(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
// Set default DC
args := structs.ServiceSpecificRequest{}
if done := s.parse(resp, req, &args.Datacenter, &args.QueryOptions); done {
return nil, nil
}
// Check for a tag
params := req.URL.Query()
if _, ok := params["tag"]; ok {
args.ServiceTag = params.Get("tag")
args.TagFilter = true
}
// Pull out the service name
args.ServiceName = strings.TrimPrefix(req.URL.Path, "/v1/health/service/")
if args.ServiceName == "" {
resp.WriteHeader(400)
resp.Write([]byte("Missing service name"))
return nil, nil
}
// Make the RPC request
var out structs.IndexedCheckServiceNodes
defer setMeta(resp, &out.QueryMeta)
if err := s.agent.RPC("Health.ServiceNodes", &args, &out); err != nil {
return nil, err
}
// Filter to only passing if specified
if _, ok := params["passing"]; ok {
out.Nodes = filterNonPassing(out.Nodes)
}
return out.Nodes, nil
}
// serviceLookup is used to handle a service query
func (d *DNSServer) serviceLookup(network, datacenter, service, tag string, req, resp *dns.Msg) {
// Make an RPC request
args := structs.ServiceSpecificRequest{
Datacenter: datacenter,
ServiceName: service,
ServiceTag: tag,
TagFilter: tag != "",
QueryOptions: structs.QueryOptions{
Token: d.agent.config.ACLToken,
AllowStale: d.config.AllowStale,
},
}
var out structs.IndexedCheckServiceNodes
RPC:
if err := d.agent.RPC("Health.ServiceNodes", &args, &out); err != nil {
d.logger.Printf("[ERR] dns: rpc error: %v", err)
resp.SetRcode(req, dns.RcodeServerFailure)
return
}
// Verify that request is not too stale, redo the request
if args.AllowStale && out.LastContact > d.config.MaxStale {
args.AllowStale = false
d.logger.Printf("[WARN] dns: Query results too stale, re-requesting")
goto RPC
}
// If we have no nodes, return not found!
if len(out.Nodes) == 0 {
d.addSOA(d.domain, resp)
resp.SetRcode(req, dns.RcodeNameError)
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)
// Perform a random shuffle
shuffleServiceNodes(out.Nodes)
// If the network is not TCP, restrict the number of responses
if network != "tcp" && len(out.Nodes) > maxServiceResponses {
out.Nodes = out.Nodes[:maxServiceResponses]
// Flag that there are more records to return in the UDP response
if d.config.EnableTruncate {
resp.Truncated = true
}
}
// Add various responses depending on the request
qType := req.Question[0].Qtype
d.serviceNodeRecords(out.Nodes, req, resp, ttl)
if qType == dns.TypeSRV {
d.serviceSRVRecords(datacenter, out.Nodes, req, resp, ttl)
}
}