diff options
Diffstat (limited to 'middleware/kubernetes/kubernetes.go')
| -rw-r--r-- | middleware/kubernetes/kubernetes.go | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/middleware/kubernetes/kubernetes.go b/middleware/kubernetes/kubernetes.go new file mode 100644 index 000000000..25c8cab3c --- /dev/null +++ b/middleware/kubernetes/kubernetes.go @@ -0,0 +1,223 @@ +// Package kubernetes provides the kubernetes backend. +package kubernetes + +import ( + "fmt" + "strings" + "time" + + "github.com/miekg/coredns/middleware" + "github.com/miekg/coredns/middleware/kubernetes/msg" + k8sc "github.com/miekg/coredns/middleware/kubernetes/k8sclient" + "github.com/miekg/coredns/middleware/proxy" +// "github.com/miekg/coredns/middleware/singleflight" + + "github.com/miekg/dns" + "golang.org/x/net/context" +) + +type Kubernetes struct { + Next middleware.Handler + Zones []string + Proxy proxy.Proxy // Proxy for looking up names during the resolution process + Ctx context.Context +// Inflight *singleflight.Group + APIConn *k8sc.K8sConnector +} + + +func (g Kubernetes) getZoneForName(name string) (string, []string) { + /* + * getZoneForName returns the zone string that matches the name and a + * list of the DNS labels from name that are within the zone. + * For example, if "coredns.local" is a zone configured for the + * Kubernetes middleware, then getZoneForName("a.b.coredns.local") + * will return ("coredns.local", ["a", "b"]). + */ + var zone string + var serviceSegments []string + + for _, z := range g.Zones { + if dns.IsSubDomain(z, name) { + zone = z + + serviceSegments = dns.SplitDomainName(name) + serviceSegments = serviceSegments[:len(serviceSegments) - dns.CountLabel(zone)] + break + } + } + + return zone, serviceSegments +} + + +// Records looks up services in kubernetes. +// If exact is true, it will lookup just +// this name. This is used when find matches when completing SRV lookups +// for instance. +func (g Kubernetes) Records(name string, exact bool) ([]msg.Service, error) { + + fmt.Println("enter Records('", name, "', ", exact, ")") + + zone, serviceSegments := g.getZoneForName(name) + + var serviceName string + var namespace string + + // For initial implementation, assume namespace is first serviceSegment + // and service name is remaining segments. + serviceSegLen := len(serviceSegments) + if serviceSegLen >= 2 { + namespace = serviceSegments[serviceSegLen-1] + serviceName = strings.Join(serviceSegments[:serviceSegLen-1], ".") + } + // else we are looking up the zone. So handle the NS, SOA records etc. + + fmt.Println("[debug] zone: ", zone) + fmt.Println("[debug] servicename: ", serviceName) + fmt.Println("[debug] namespace: ", namespace) + fmt.Println("[debug] APIconn: ", g.APIConn) + + k8sItem := g.APIConn.GetServiceItemInNamespace(namespace, serviceName) + fmt.Println("[debug] k8s item:", k8sItem) + + switch { + case exact && k8sItem == nil: + fmt.Println("here2") + return nil, nil + } + + if k8sItem == nil { + // Did not find item in k8s + return nil, nil + } + + fmt.Println("[debug] clusterIP:", k8sItem.Spec.ClusterIP) + + for _, p := range k8sItem.Spec.Ports { + fmt.Println("[debug] host:", name) + fmt.Println("[debug] port:", p.Port) + } + + clusterIP := k8sItem.Spec.ClusterIP + var records []msg.Service + for _, p := range k8sItem.Spec.Ports{ + s := msg.Service{Host: clusterIP, Port: p.Port} + records = append(records, s) + } + + return records, nil +} + +/* +// Get performs the call to the Kubernetes http API. +func (g Kubernetes) Get(path string, recursive bool) (bool, error) { + + fmt.Println("[debug] in Get path: ", path) + fmt.Println("[debug] in Get recursive: ", recursive) + + return false, nil +} +*/ + +func (g Kubernetes) splitDNSName(name string) []string { + l := dns.SplitDomainName(name) + + for i, j := 0, len(l)-1; i < j; i, j = i+1, j-1 { + l[i], l[j] = l[j], l[i] + } + + return l +} + +// skydns/local/skydns/east/staging/web +// skydns/local/skydns/west/production/web +// +// skydns/local/skydns/*/*/web +// skydns/local/skydns/*/web + +// loopNodes recursively loops through the nodes and returns all the values. The nodes' keyname +// will be match against any wildcards when star is true. +/* +func (g Kubernetes) loopNodes(ns []*etcdc.Node, nameParts []string, star bool, bx map[msg.Service]bool) (sx []msg.Service, err error) { + if bx == nil { + bx = make(map[msg.Service]bool) + } +Nodes: + for _, n := range ns { + if n.Dir { + nodes, err := g.loopNodes(n.Nodes, nameParts, star, bx) + if err != nil { + return nil, err + } + sx = append(sx, nodes...) + continue + } + if star { + keyParts := strings.Split(n.Key, "/") + for i, n := range nameParts { + if i > len(keyParts)-1 { + // name is longer than key + continue Nodes + } + if n == "*" || n == "any" { + continue + } + if keyParts[i] != n { + continue Nodes + } + } + } + serv := new(msg.Service) + if err := json.Unmarshal([]byte(n.Value), serv); err != nil { + return nil, err + } + b := msg.Service{Host: serv.Host, Port: serv.Port, Priority: serv.Priority, Weight: serv.Weight, Text: serv.Text, Key: n.Key} + if _, ok := bx[b]; ok { + continue + } + bx[b] = true + + serv.Key = n.Key + serv.Ttl = g.Ttl(n, serv) + if serv.Priority == 0 { + serv.Priority = priority + } + sx = append(sx, *serv) + } + return sx, nil +} + +// Ttl returns the smaller of the kubernetes TTL and the service's +// TTL. If neither of these are set (have a zero value), a default is used. +func (g Kubernetes) Ttl(node *etcdc.Node, serv *msg.Service) uint32 { + kubernetesTtl := uint32(node.TTL) + + if kubernetesTtl == 0 && serv.Ttl == 0 { + return ttl + } + if kubernetesTtl == 0 { + return serv.Ttl + } + if serv.Ttl == 0 { + return kubernetesTtl + } + if kubernetesTtl < serv.Ttl { + return kubernetesTtl + } + return serv.Ttl +} +*/ + +// kubernetesNameError checks if the error is ErrorCodeKeyNotFound from kubernetes. +func isKubernetesNameError(err error) bool { + return false +} + +const ( + priority = 10 // default priority when nothing is set + ttl = 300 // default ttl when nothing is set + minTtl = 60 + hostmaster = "hostmaster" + k8sTimeout = 5 * time.Second +) |