Golang NodeSpecificRequest.AllowStale方法代码示例

// UINodeInfo is used to get info on a single node in a given datacenter. We return a
// NodeInfo which provides overview information for the node
func (s *HTTPServer) UINodeInfo(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
	// Parse arguments
	args := structs.NodeSpecificRequest{}
	if done := s.parse(resp, req, &args.Datacenter, &args.QueryOptions); done {
		return nil, nil
	}

	// Verify we have some DC, or use the default
	args.Node = strings.TrimPrefix(req.URL.Path, "/v1/internal/ui/node/")
	if args.Node == "" {
		resp.WriteHeader(400)
		resp.Write([]byte("Missing node name"))
		return nil, nil
	}

	// Make the RPC request
	var out structs.IndexedNodeDump
	defer setMeta(resp, &out.QueryMeta)
RPC:
	if err := s.agent.RPC("Internal.NodeInfo", &args, &out); err != nil {
		// Retry the request allowing stale data if no leader
		if strings.Contains(err.Error(), structs.ErrNoLeader.Error()) && !args.AllowStale {
			args.AllowStale = true
			goto RPC
		}
		return nil, err
	}

	// Return only the first entry
	if len(out.Dump) > 0 {
		return out.Dump[0], nil
	}
	return nil, nil
}

// nodeLookup is used to handle a node query
func (d *DNSServer) nodeLookup(network, datacenter, node string, req, resp *dns.Msg) {
	// Only handle ANY, A and AAAA type requests
	qType := req.Question[0].Qtype
	if qType != dns.TypeANY && qType != dns.TypeA && qType != dns.TypeAAAA {
		return
	}

	// Make an RPC request
	args := structs.NodeSpecificRequest{
		Datacenter: datacenter,
		Node:       node,
		QueryOptions: structs.QueryOptions{
			Token:      d.agent.config.ACLToken,
			AllowStale: *d.config.AllowStale,
		},
	}
	var out structs.IndexedNodeServices
RPC:
	if err := d.agent.RPC("Catalog.NodeServices", &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 {
		if out.LastContact > d.config.MaxStale {
			args.AllowStale = false
			d.logger.Printf("[WARN] dns: Query results too stale, re-requesting")
			goto RPC
		} else if out.LastContact > staleCounterThreshold {
			metrics.IncrCounter([]string{"consul", "dns", "stale_queries"}, 1)
		}
	}

	// If we have no address, return not found!
	if out.NodeServices == nil {
		d.addSOA(d.domain, resp)
		resp.SetRcode(req, dns.RcodeNameError)
		return
	}

	// Add the node record
	n := out.NodeServices.Node
	addr := translateAddress(d.agent.config, datacenter, n.Address, n.TaggedAddresses)
	records := d.formatNodeRecord(out.NodeServices.Node, addr,
		req.Question[0].Name, qType, d.config.NodeTTL)
	if records != nil {
		resp.Answer = append(resp.Answer, records...)
	}
}

// nodeLookup is used to handle a node query
func (d *DNSServer) nodeLookup(network, datacenter, node string, req, resp *dns.Msg) {
	// Only handle ANY and A type requests
	qType := req.Question[0].Qtype
	if qType != dns.TypeANY && qType != dns.TypeA {
		return
	}

	// Make an RPC request
	args := structs.NodeSpecificRequest{
		Datacenter: datacenter,
		Node:       node,
		QueryOptions: structs.QueryOptions{
			Token:      d.agent.config.ACLToken,
			AllowStale: d.config.AllowStale,
		},
	}
	var out structs.IndexedNodeServices
RPC:
	if err := d.agent.RPC("Catalog.NodeServices", &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 address, return not found!
	if out.NodeServices == nil {
		resp.SetRcode(req, dns.RcodeNameError)
		return
	}

	// Add the node record
	records := d.formatNodeRecord(&out.NodeServices.Node, out.NodeServices.Node.Address,
		req.Question[0].Name, qType, d.config.NodeTTL)
	if records != nil {
		resp.Answer = append(resp.Answer, records...)
	}
}