k8s middleware cleanup, testcases, basic SRV (#181)

* Removing unnecessary gitignore pattern

* Updating Makefile to run unittests for subpackages

* Adding Corefile validation to ignore overlapping zones

* Fixing SRV query handling

* Updating README.md now that SRV works

* Fixing debug message, adding code comment

* Clarifying implementation of zone normalization

* "Overlapping zones" is ill-defined. Reimplemented zone overlap/subzone
  checking to contain these functions in k8s middleware and provide
  better code comments explaining the normalization.

* Separate build verbosity from test verbosity

* Cleaning up comments to match repo code style

* Merging warning messages into single message
* Moving function docs to before function declaration

* Adding test cases for k8sclient connector

* Tests cover connector create and setting base url
* Fixed bugs in connector create and setting base url functions

* Updaing README to group and order development work

* Priority focused on achieving functional parity with SkyDNS.

* Adding work items to README and cleaning up formatting

* More README format cleaning

* List formating

* Refactoring k8s API call to allow dependency injection

* Add test cases for data parsing from k8s into dataobject structures

* URL is dependency-injected to allow replacement with a mock http
  server during test execution

* Adding more data validation for JSON parsing tests

* Adding test case for GetResourceList()

* Adding notes about SkyDNS embedded IP and port record names

* Marked test case implemented.

* Fixing formatting for example command.

* Fixing formatting

* Adding notes about Docker image building.

* Adding SkyDNS work item

* Updating TODO list

* Adding name template to Corefile to specify how k8s record names are assembled

* Adding template support for multi-segment zones

* Updating example CoreFile for k8s with template comment

* Misc whitespace cleanup

* Adding SkyDNS naming notes

* Adding namespace filtering to CoreFile config

* Updating example k8sCoreFile to specify namespaces

* Removing unused codepath

* Adding check for valid namespace

* More README TODO restructuring to focus effort

* Adding template validation while parsing CoreFile

* Record name template is considered invalid if it contains a symbol of the form ${bar} where the symbol
  "${bar}" is not an accepted template symbol.

* Refactoring generation of answer records

* Parse typeName out of query string
* Refactor answer record creation as operation over list of ServiceItems

* Moving k8s API caching into SkyDNS equivalency segment

* Adding function to assemble record names from template

* Warning: This commit may be broken. Syncing to get laptop code over to dev machine.

* More todo notes

* Adding comment describing sample test data.

* Update k8sCorefile

* Adding comment

* Adding filtering support for kubernetes "type"

* Required refactoring to support reuse of the StringInSlice function.

* Cleaning up formatting

* Adding note about SkyDNS supporting word "any".

* baseUrl -> baseURL

* Also removed debug statement from core/setup/kubernetes.go

* Fixing test breaking from Url -> URL naming changes

* Changing record name template language ${...} -> {...}

* Fix formatting with go fmt

* Updating all k8sclient data getters to return error value

* Adding error message to k8sclient data accessors

* Cleaning up setup for kubernetes

* Removed verbose nils in initial k8s middleware instance
* Set reasonable defaults if CoreFile has no parameters in the
kubernetes block. (k8s endpoint, and name template)

* Formatting cleanup -- go fmt

1 files changed, 120 insertions, 83 deletions

diff --git a/middleware/kubernetes/kubernetes.go b/middleware/kubernetes/kubernetes.go
index 25c8cab3c..d6d93f809 100644
--- a/middleware/kubernetes/kubernetes.go
+++ b/middleware/kubernetes/kubernetes.go
@@ -2,111 +2,148 @@
 package kubernetes
 
 import (
-    "fmt"
-	"strings"
+	"errors"
+	"fmt"
 	"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/kubernetes/msg"
+	"github.com/miekg/coredns/middleware/kubernetes/nametemplate"
+	"github.com/miekg/coredns/middleware/kubernetes/util"
 	"github.com/miekg/coredns/middleware/proxy"
-//	"github.com/miekg/coredns/middleware/singleflight"
+	//	"github.com/miekg/coredns/middleware/singleflight"
 
-    "github.com/miekg/dns"
+	"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
+	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
+	NameTemplate *nametemplate.NameTemplate
+	Namespaces   *[]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"]).
 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
-} 
+	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) {
+	var (
+		serviceName string
+		namespace   string
+		typeName    string
+	)
+
+	fmt.Println("enter Records('", name, "', ", exact, ")")
+	zone, serviceSegments := g.getZoneForName(name)
+
+	/*
+	   // 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.
+	*/
+
+	// TODO: Implementation above globbed together segments for the serviceName if
+	//       multiple segments remained. Determine how to do similar globbing using
+	//		 the template-based implementation.
+	namespace = g.NameTemplate.GetNamespaceFromSegmentArray(serviceSegments)
+	serviceName = g.NameTemplate.GetServiceFromSegmentArray(serviceSegments)
+	typeName = g.NameTemplate.GetTypeFromSegmentArray(serviceSegments)
+
+	fmt.Println("[debug] exact: ", exact)
+	fmt.Println("[debug] zone: ", zone)
+	fmt.Println("[debug] servicename: ", serviceName)
+	fmt.Println("[debug] namespace: ", namespace)
+	fmt.Println("[debug] typeName: ", typeName)
+	fmt.Println("[debug] APIconn: ", g.APIConn)
+
+	// TODO: Implement wildcard support to allow blank namespace value
+	if namespace == "" {
+		err := errors.New("Parsing query string did not produce a namespace value")
+		fmt.Printf("[ERROR] %v\n", err)
+		return nil, err
+	}
 
-    fmt.Println("enter Records('", name, "', ", exact, ")") 
-
-    zone, serviceSegments := g.getZoneForName(name)
+	// Abort if the namespace is not published per CoreFile
+	if g.Namespaces != nil && !util.StringInSlice(namespace, *g.Namespaces) {
+		return nil, nil
+	}
 
-    var serviceName string
-    var namespace string
+	k8sItems, err := g.APIConn.GetServiceItemsInNamespace(namespace, serviceName)
+	fmt.Println("[debug] k8s items:", k8sItems)
 
-    // 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.
+	if err != nil {
+		fmt.Printf("[ERROR] Got error while looking up ServiceItems. Error is: %v\n", err)
+		return nil, err
+	}
+	if k8sItems == nil {
+		// Did not find item in k8s
+		return nil, nil
+	}
 
-    fmt.Println("[debug] zone: ", zone)
-    fmt.Println("[debug] servicename: ", serviceName)
-    fmt.Println("[debug] namespace: ", namespace)
-    fmt.Println("[debug] APIconn: ", g.APIConn)
+	//	test := g.NameTemplate.GetRecordNameFromNameValues(nametemplate.NameValues{ServiceName: serviceName, TypeName: typeName, Namespace: namespace, Zone: zone})
+	//	fmt.Printf("[debug] got recordname %v\n", test)
 
-    k8sItem := g.APIConn.GetServiceItemInNamespace(namespace, serviceName)
-    fmt.Println("[debug] k8s item:", k8sItem)
+	records := g.getRecordsForServiceItems(k8sItems, name)
 
-    switch {
-        case exact && k8sItem == nil:
-            fmt.Println("here2")
-            return nil, nil
-    }
+	return records, nil
+}
 
-    if k8sItem == nil {
-        // Did not find item in k8s
-        return nil, nil
-    }
+// TODO: assemble name from parts found in k8s data based on name template rather than reusing query string
+func (g Kubernetes) getRecordsForServiceItems(serviceItems []*k8sc.ServiceItem, name string) []msg.Service {
+	var records []msg.Service
 
-    fmt.Println("[debug] clusterIP:", k8sItem.Spec.ClusterIP)
+	for _, item := range serviceItems {
+		fmt.Println("[debug] clusterIP:", item.Spec.ClusterIP)
+		for _, p := range item.Spec.Ports {
+			fmt.Println("[debug]    port:", p.Port)
+		}
 
-    for _, p := range k8sItem.Spec.Ports {
-        fmt.Println("[debug]    host:", name)
-        fmt.Println("[debug]    port:", p.Port)
-    }
+		clusterIP := item.Spec.ClusterIP
 
-    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)
-    }
+		s := msg.Service{Host: name}
+		records = append(records, s)
+		for _, p := range item.Spec.Ports {
+			s := msg.Service{Host: clusterIP, Port: p.Port}
+			records = append(records, s)
+		}
+	}
 
-    return records, nil
+	fmt.Printf("[debug] records from getRecordsForServiceItems(): %v\n", records)
+	return records
 }
 
 /*
@@ -121,13 +158,13 @@ func (g Kubernetes) Get(path string, recursive bool) (bool, error) {
 */
 
 func (g Kubernetes) splitDNSName(name string) []string {
-    l := dns.SplitDomainName(name)
+	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]
-    }
+	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
+	return l
 }
 
 // skydns/local/skydns/east/staging/web
@@ -215,9 +252,9 @@ func isKubernetesNameError(err error) bool {
 }
 
 const (
-	priority    = 10  // default priority when nothing is set
-	ttl         = 300 // default ttl when nothing is set
-	minTtl      = 60
-	hostmaster  = "hostmaster"
+	priority   = 10  // default priority when nothing is set
+	ttl        = 300 // default ttl when nothing is set
+	minTtl     = 60
+	hostmaster = "hostmaster"
 	k8sTimeout = 5 * time.Second
 )