Adding wildcard support (#190)

* Commenting out unused functions. TODO: remove when it is not needed

* Update README with namespace and template example

* Adding note about changing the record name format via a template

* Adding test scripts to automate k8s startup

* Automating k8s namespace creation

* Adding automation to start 4 k8s services

* Updating documentation for k8s tests

* Avoid downloading kubectl if already exists

* Adding debug statement when namespace is not exposed.

* Adding basic kubernetes integration tests

* Makefile now contains a "testk8s" target. This target requires k8s to
  be running.
* Adding test/kubernetes_test.go file with a couple of basic A record
  tests.

* Updating k8s integration tests to only run k8s integration tests

* Adding support for namespace wildcards

* Refactoring to move filtering logic to kubernetes.go file

* go fmt fixes

* Adding wildcard support for namespaces and service names

* Kubernetes integration tests updated for A records.
* Expanded record name assembly for answer section not yet implemented.
* Refactoring to focus k8sclient code just on accessing k8s API.
 Filtering now handled in kubernetes.go

* Adding wildcard test cases

* Adding skydns startup script. (To allow side by side testing of wildcards.)
* Commenting out record name assmebly based on NameTemplate. Need to improve template before this makes sense.

* Adding basic SRV integration tests

* Need to add verification for additional answer section

* Fixing comments and formatting

* Moving wildcard constants to vars

* Travis test execution appears to be failing on access to these
 constants

* Fixing access to util package

* Trying to work around Travis test bug

* Reverting to access kubernetes/util as "util"

Travis breakage is due to "Infoblox-CTO" in src path

1 files changed, 182 insertions, 0 deletions

diff --git a/test/kubernetes_test.go b/test/kubernetes_test.go
new file mode 100644
index 000000000..6f6599d41
--- /dev/null
+++ b/test/kubernetes_test.go
@@ -0,0 +1,182 @@
+// +build k8sIntegration
+
+package test
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"testing"
+
+	"github.com/miekg/dns"
+)
+
+// Test data for A records
+var testdataLookupA = []struct {
+	Query            string
+	TotalAnswerCount int
+	ARecordCount     int
+}{
+	// Matching queries
+	{"mynginx.demo.coredns.local.", 1, 1}, // One A record, should exist
+
+	// Failure queries
+	{"mynginx.test.coredns.local.", 0, 0},                     // One A record, is not exposed
+	{"someservicethatdoesnotexist.demo.coredns.local.", 0, 0}, // Record does not exist
+
+	// Namespace wildcards
+	{"mynginx.*.coredns.local.", 1, 1},                       // One A record, via wildcard namespace
+	{"mynginx.any.coredns.local.", 1, 1},                     // One A record, via wildcard namespace
+	{"someservicethatdoesnotexist.*.coredns.local.", 0, 0},   // Record does not exist with wildcard for namespace
+	{"someservicethatdoesnotexist.any.coredns.local.", 0, 0}, // Record does not exist with wildcard for namespace
+	{"*.demo.coredns.local.", 2, 2},                          // Two A records, via wildcard
+	{"any.demo.coredns.local.", 2, 2},                        // Two A records, via wildcard
+	{"*.test.coredns.local.", 0, 0},                          // Two A record, via wildcard that is not exposed
+	{"any.test.coredns.local.", 0, 0},                        // Two A record, via wildcard that is not exposed
+	{"*.*.coredns.local.", 2, 2},                             // Two A records, via namespace and service wildcard
+}
+
+// Test data for SRV records
+var testdataLookupSRV = []struct {
+	Query            string
+	TotalAnswerCount int
+	//	ARecordCount     int
+	SRVRecordCount int
+}{
+	// Matching queries
+	{"mynginx.demo.coredns.local.", 1, 1}, // One SRV record, should exist
+
+	// Failure queries
+	{"mynginx.test.coredns.local.", 0, 0},                     // One SRV record, is not exposed
+	{"someservicethatdoesnotexist.demo.coredns.local.", 0, 0}, // Record does not exist
+
+	// Namespace wildcards
+	{"mynginx.*.coredns.local.", 1, 1},                       // One SRV record, via wildcard namespace
+	{"mynginx.any.coredns.local.", 1, 1},                     // One SRV record, via wildcard namespace
+	{"someservicethatdoesnotexist.*.coredns.local.", 0, 0},   // Record does not exist with wildcard for namespace
+	{"someservicethatdoesnotexist.any.coredns.local.", 0, 0}, // Record does not exist with wildcard for namespace
+	{"*.demo.coredns.local.", 1, 1},                          // One SRV record, via wildcard
+	{"any.demo.coredns.local.", 1, 1},                        // One SRV record, via wildcard
+	{"*.test.coredns.local.", 0, 0},                          // One SRV record, via wildcard that is not exposed
+	{"any.test.coredns.local.", 0, 0},                        // One SRV record, via wildcard that is not exposed
+	{"*.*.coredns.local.", 1, 1},                             // One SRV record, via namespace and service wildcard
+}
+
+// checkKubernetesRunning performs a basic
+func checkKubernetesRunning() bool {
+	_, err := http.Get("http://localhost:8080/api/v1")
+	return err == nil
+}
+
+func TestK8sIntegration(t *testing.T) {
+	t.Log("   === RUN testLookupA")
+	testLookupA(t)
+	t.Log("   === RUN testLookupSRV")
+	testLookupSRV(t)
+}
+
+func testLookupA(t *testing.T) {
+	if !checkKubernetesRunning() {
+		t.Skip("Skipping Kubernetes Integration tests. Kubernetes is not running")
+	}
+
+	// Note: Use different port to avoid conflict with servers used in other tests.
+	coreFile :=
+		`.:2053 {
+    kubernetes coredns.local {
+		endpoint http://localhost:8080
+		namespaces demo
+    }
+`
+
+	server, _, udp, err := Server(t, coreFile)
+	if err != nil {
+		t.Fatal("Could not get server: %s", err)
+	}
+	defer server.Stop()
+
+	log.SetOutput(ioutil.Discard)
+
+	for _, testData := range testdataLookupA {
+		t.Logf("[log] Testing query string: '%v'\n", testData.Query)
+		dnsClient := new(dns.Client)
+		dnsMessage := new(dns.Msg)
+
+		dnsMessage.SetQuestion(testData.Query, dns.TypeA)
+		dnsMessage.SetEdns0(4096, true)
+
+		res, _, err := dnsClient.Exchange(dnsMessage, udp)
+		if err != nil {
+			t.Fatal("Could not send query: %s", err)
+		}
+		// Count A records in the answer section
+		ARecordCount := 0
+		for _, a := range res.Answer {
+			if a.Header().Rrtype == dns.TypeA {
+				ARecordCount++
+			}
+		}
+
+		if ARecordCount != testData.ARecordCount {
+			t.Errorf("Expected '%v' A records in response. Instead got '%v' A records. Test query string: '%v'", testData.ARecordCount, ARecordCount, testData.Query)
+		}
+		if len(res.Answer) != testData.TotalAnswerCount {
+			t.Errorf("Expected '%v' records in answer section. Instead got '%v' records in answer section. Test query string: '%v'", testData.TotalAnswerCount, len(res.Answer), testData.Query)
+		}
+	}
+}
+
+func testLookupSRV(t *testing.T) {
+	if !checkKubernetesRunning() {
+		t.Skip("Skipping Kubernetes Integration tests. Kubernetes is not running")
+	}
+
+	// Note: Use different port to avoid conflict with servers used in other tests.
+	coreFile :=
+		`.:2054 {
+    kubernetes coredns.local {
+		endpoint http://localhost:8080
+		namespaces demo
+    }
+`
+
+	server, _, udp, err := Server(t, coreFile)
+	if err != nil {
+		t.Fatal("Could not get server: %s", err)
+	}
+	defer server.Stop()
+
+	log.SetOutput(ioutil.Discard)
+
+	// TODO: Add checks for A records in additional section
+
+	for _, testData := range testdataLookupSRV {
+		t.Logf("[log] Testing query string: '%v'\n", testData.Query)
+		dnsClient := new(dns.Client)
+		dnsMessage := new(dns.Msg)
+
+		dnsMessage.SetQuestion(testData.Query, dns.TypeSRV)
+		dnsMessage.SetEdns0(4096, true)
+
+		res, _, err := dnsClient.Exchange(dnsMessage, udp)
+		if err != nil {
+			t.Fatal("Could not send query: %s", err)
+		}
+		// Count SRV records in the answer section
+		srvRecordCount := 0
+		for _, a := range res.Answer {
+			fmt.Printf("RR: %v\n", a)
+			if a.Header().Rrtype == dns.TypeSRV {
+				srvRecordCount++
+			}
+		}
+
+		if srvRecordCount != testData.SRVRecordCount {
+			t.Errorf("Expected '%v' SRV records in response. Instead got '%v' SRV records. Test query string: '%v'", testData.SRVRecordCount, srvRecordCount, testData.Query)
+		}
+		if len(res.Answer) != testData.TotalAnswerCount {
+			t.Errorf("Expected '%v' records in answer section. Instead got '%v' records in answer section. Test query string: '%v'", testData.TotalAnswerCount, len(res.Answer), testData.Query)
+		}
+	}
+}