mirror of https://github.com/status-im/consul.git
Resolve Consul CNAME records on external services (#2444)
This commit is contained in:
Kyle Havlovitz
GitHub
parent
757a45ed7f
commit
554440ab1d
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@ -50,8 +50,8 @@ func (d *DNSServer) Shutdown() {
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// NewDNSServer starts a new DNS server to provide an agent interface
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func NewDNSServer(agent *Agent, config *DNSConfig, logOutput io.Writer, domain string, bind string, recursors []string) (*DNSServer, error) {
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// Make sure domain is FQDN
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domain = dns.Fqdn(domain)
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// Make sure domain is FQDN, make it case insensitive for ServeMux
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domain = dns.Fqdn(strings.ToLower(domain))
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// Construct the DNS components
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mux := dns.NewServeMux()
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@ -877,6 +877,19 @@ func (d *DNSServer) handleRecurse(resp dns.ResponseWriter, req *dns.Msg) {
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// resolveCNAME is used to recursively resolve CNAME records
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func (d *DNSServer) resolveCNAME(name string) []dns.RR {
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// If the CNAME record points to a Consul address, resolve it internally
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// Convert query to lowercase because DNS is case insensitive; d.domain is
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// already converted
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if strings.HasSuffix(strings.ToLower(name), "."+d.domain) {
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req := &dns.Msg{}
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resp := &dns.Msg{}
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req.SetQuestion(name, dns.TypeANY)
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d.dispatch("udp", req, resp)
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return resp.Answer
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}
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// Do nothing if we don't have a recursor
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if len(d.recursors) == 0 {
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return nil
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@ -639,6 +639,335 @@ func TestDNS_ServiceLookup(t *testing.T) {
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}
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}
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func TestDNS_ExternalServiceLookup(t *testing.T) {
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dir, srv := makeDNSServer(t)
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defer os.RemoveAll(dir)
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defer srv.agent.Shutdown()
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testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
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// Register a node with an external service.
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{
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args := &structs.RegisterRequest{
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Datacenter: "dc1",
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Node: "foo",
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Address: "www.google.com",
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Service: &structs.NodeService{
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Service: "db",
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Port: 12345,
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},
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}
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var out struct{}
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if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
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t.Fatalf("err: %v", err)
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}
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}
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// Look up the service
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questions := []string{
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"db.service.consul.",
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}
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for _, question := range questions {
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m := new(dns.Msg)
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m.SetQuestion(question, dns.TypeSRV)
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c := new(dns.Client)
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addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
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in, _, err := c.Exchange(m, addr.String())
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if err != nil {
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t.Fatalf("err: %v", err)
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}
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if len(in.Answer) != 1 {
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t.Fatalf("Bad: %#v", in)
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}
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srvRec, ok := in.Answer[0].(*dns.SRV)
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if !ok {
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t.Fatalf("Bad: %#v", in.Answer[0])
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}
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if srvRec.Port != 12345 {
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t.Fatalf("Bad: %#v", srvRec)
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}
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if srvRec.Target != "foo.node.dc1.consul." {
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t.Fatalf("Bad: %#v", srvRec)
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}
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if srvRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Answer[0])
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}
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cnameRec, ok := in.Extra[0].(*dns.CNAME)
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if !ok {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Hdr.Name != "foo.node.dc1.consul." {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Target != "www.google.com." {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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}
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}
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func TestDNS_ExternalServiceToConsulCNAMELookup(t *testing.T) {
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dir, srv := makeDNSServerConfig(t, func(c *Config) {
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c.Domain = "CONSUL."
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}, nil)
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defer os.RemoveAll(dir)
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defer srv.agent.Shutdown()
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testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
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// Register the initial node with a service
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{
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args := &structs.RegisterRequest{
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Datacenter: "dc1",
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Node: "web",
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Address: "127.0.0.1",
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Service: &structs.NodeService{
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Service: "web",
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Port: 12345,
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},
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}
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var out struct{}
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if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
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t.Fatalf("err: %v", err)
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}
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}
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// Register an external service pointing to the 'web' service
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{
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args := &structs.RegisterRequest{
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Datacenter: "dc1",
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Node: "alias",
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Address: "web.service.consul",
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Service: &structs.NodeService{
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Service: "alias",
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Port: 12345,
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},
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}
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var out struct{}
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if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
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t.Fatalf("err: %v", err)
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}
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}
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// Look up the service directly
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questions := []string{
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"alias.service.consul.",
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"alias.service.CoNsUl.",
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}
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for _, question := range questions {
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m := new(dns.Msg)
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m.SetQuestion(question, dns.TypeSRV)
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c := new(dns.Client)
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addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
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in, _, err := c.Exchange(m, addr.String())
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if err != nil {
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t.Fatalf("err: %v", err)
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}
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if len(in.Answer) != 1 {
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t.Fatalf("Bad: %#v", in)
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}
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srvRec, ok := in.Answer[0].(*dns.SRV)
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if !ok {
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t.Fatalf("Bad: %#v", in.Answer[0])
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}
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if srvRec.Port != 12345 {
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t.Fatalf("Bad: %#v", srvRec)
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}
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if srvRec.Target != "alias.node.dc1.consul." {
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t.Fatalf("Bad: %#v", srvRec)
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}
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if srvRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Answer[0])
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}
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if len(in.Extra) != 2 {
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t.Fatalf("Bad: %#v", in)
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}
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cnameRec, ok := in.Extra[0].(*dns.CNAME)
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if !ok {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Hdr.Name != "alias.node.dc1.consul." {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Target != "web.service.consul." {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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aRec, ok := in.Extra[1].(*dns.A)
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if !ok {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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if aRec.Hdr.Name != "web.service.consul." {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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if aRec.A.String() != "127.0.0.1" {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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if aRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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}
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}
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func TestDNS_ExternalServiceToConsulCNAMENestedLookup(t *testing.T) {
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dir, srv := makeDNSServer(t)
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defer os.RemoveAll(dir)
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defer srv.agent.Shutdown()
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testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
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// Register the initial node with a service
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{
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args := &structs.RegisterRequest{
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Datacenter: "dc1",
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Node: "web",
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Address: "127.0.0.1",
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Service: &structs.NodeService{
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Service: "web",
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Port: 12345,
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},
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}
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var out struct{}
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if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
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t.Fatalf("err: %v", err)
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}
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}
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// Register an external service pointing to the 'web' service
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{
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args := &structs.RegisterRequest{
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Datacenter: "dc1",
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Node: "alias",
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Address: "web.service.consul",
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Service: &structs.NodeService{
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Service: "alias",
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Port: 12345,
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},
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}
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var out struct{}
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if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
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t.Fatalf("err: %v", err)
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}
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}
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// Register an external service pointing to the 'alias' service
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{
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args := &structs.RegisterRequest{
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Datacenter: "dc1",
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Node: "alias2",
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Address: "alias.service.consul",
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Service: &structs.NodeService{
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Service: "alias2",
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Port: 12345,
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},
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}
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var out struct{}
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if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
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t.Fatalf("err: %v", err)
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}
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}
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// Look up the service directly
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questions := []string{
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"alias2.service.consul.",
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}
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for _, question := range questions {
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m := new(dns.Msg)
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m.SetQuestion(question, dns.TypeSRV)
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c := new(dns.Client)
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addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
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in, _, err := c.Exchange(m, addr.String())
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if err != nil {
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t.Fatalf("err: %v", err)
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}
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if len(in.Answer) != 1 {
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t.Fatalf("Bad: %#v", in)
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}
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srvRec, ok := in.Answer[0].(*dns.SRV)
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if !ok {
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t.Fatalf("Bad: %#v", in.Answer[0])
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}
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if srvRec.Port != 12345 {
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t.Fatalf("Bad: %#v", srvRec)
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}
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if srvRec.Target != "alias2.node.dc1.consul." {
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t.Fatalf("Bad: %#v", srvRec)
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}
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if srvRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Answer[0])
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}
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if len(in.Extra) != 3 {
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t.Fatalf("Bad: %#v", in)
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}
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cnameRec, ok := in.Extra[0].(*dns.CNAME)
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if !ok {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Hdr.Name != "alias2.node.dc1.consul." {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Target != "alias.service.consul." {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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if cnameRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Extra[0])
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}
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cnameRec, ok = in.Extra[1].(*dns.CNAME)
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if !ok {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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if cnameRec.Hdr.Name != "alias.service.consul." {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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if cnameRec.Target != "web.service.consul." {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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if cnameRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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aRec, ok := in.Extra[2].(*dns.A)
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if !ok {
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t.Fatalf("Bad: %#v", in.Extra[2])
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}
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if aRec.Hdr.Name != "web.service.consul." {
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t.Fatalf("Bad: %#v", in.Extra[1])
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}
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if aRec.A.String() != "127.0.0.1" {
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t.Fatalf("Bad: %#v", in.Extra[2])
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}
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if aRec.Hdr.Ttl != 0 {
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t.Fatalf("Bad: %#v", in.Extra[2])
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}
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}
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}
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func TestDNS_ServiceLookup_ServiceAddress(t *testing.T) {
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dir, srv := makeDNSServer(t)
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defer os.RemoveAll(dir)
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@ -1404,8 +1733,19 @@ func TestDNS_RecursorTimeout(t *testing.T) {
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serverClientTimeout := 3 * time.Second
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testClientTimeout := serverClientTimeout + 5*time.Second
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resolverAddr, err := net.ResolveUDPAddr("udp", "127.0.0.1:0")
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if err != nil {
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t.Error(err)
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}
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resolver, err := net.ListenUDP("udp", resolverAddr)
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if err != nil {
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t.Error(err)
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}
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defer resolver.Close()
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dir, srv := makeDNSServerConfig(t, func(c *Config) {
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c.DNSRecursor = "10.255.255.1" // host must cause a connection|read|write timeout
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c.DNSRecursor = resolver.LocalAddr().String() // host must cause a connection|read|write timeout
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}, func(c *DNSConfig) {
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c.RecursorTimeout = serverClientTimeout
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})
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