Beispiel #1
0
// 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{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 {
		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]
	}

	// 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)
	}
}
Beispiel #2
0
// 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
	}

	// 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 = out.Nodes.Filter(d.config.OnlyPassing)

	// If we have no nodes, return not found!
	if len(out.Nodes) == 0 {
		d.addSOA(d.domain, resp)
		resp.SetRcode(req, dns.RcodeNameError)
		return
	}

	// Perform a random shuffle
	out.Nodes.Shuffle()

	// Add various responses depending on the request
	qType := req.Question[0].Qtype
	if qType == dns.TypeSRV {
		d.serviceSRVRecords(datacenter, out.Nodes, req, resp, ttl)
	} else {
		d.serviceNodeRecords(datacenter, out.Nodes, req, resp, ttl)
	}

	// If the network is not TCP, restrict the number of responses
	if network != "tcp" {
		wasTrimmed := trimUDPResponse(d.config, resp)

		// Flag that there are more records to return in the UDP response
		if wasTrimmed && d.config.EnableTruncate {
			resp.Truncated = true
		}
	}

	// If the answer is empty and the response isn't truncated, return not found
	if len(resp.Answer) == 0 && !resp.Truncated {
		d.addSOA(d.domain, resp)
		return
	}
}