Unit tests for cache invalidations as a result of names updates

nameserver/server_cache_test.go

@@ -0,0 +1,105 @@
+package nameserver
+
+import (
+	"fmt"
+	"github.com/benbjohnson/clock"
+	"github.com/miekg/dns"
+	. "github.com/weaveworks/weave/common"
+	wt "github.com/weaveworks/weave/testing"
+	"net"
+	"testing"
+	"time"
+)
+
+// Check if the names updates lead to cache invalidations
+func TestServerCacheRefresh(t *testing.T) {
+	const (
+		containerID     = "somecontainer"
+		testName1       = "first.weave.local."
+		testName2       = "second.weave.local."
+		refreshInterval = int(localTTL) / 3
+	)
+
+	InitDefaultLogging(testing.Verbose())
+	Info.Println("TestServerCacheRefresh starting")
+
+	clk := clock.NewMock()
+	forwardClock := func(secs int) {
+		Debug.Printf(">>>>>>> Moving clock forward %d seconds - Time traveling >>>>>>>", secs)
+		clk.Add(time.Duration(secs) * time.Second)
+		Debug.Printf("<<<<<<< Time travel finished! We are at %s <<<<<<<", clk.Now())
+	}
+
+	Debug.Printf("Creating 2 zone databases")
+	zoneConfig := ZoneConfig{
+		RefreshInterval: refreshInterval,
+		Clock:           clk,
+	}
+	dbs := newZoneDbsWithMockedMDns(2, zoneConfig)
+	dbs.Start()
+	defer dbs.Stop()
+
+	Debug.Printf("Creating a cache")
+	cache, err := NewCache(1024, clk)
+	wt.AssertNoErr(t, err)
+
+	Debug.Printf("Creating a real DNS server for the first zone database and with the cache")
+	srv, err := NewDNSServer(DNSServerConfig{
+		Zone:              dbs[0].Zone,
+		Cache:             cache,
+		Clock:             clk,
+		ListenReadTimeout: testSocketTimeout,
+	})
+	wt.AssertNoErr(t, err)
+	go srv.Start()
+	defer srv.Stop()
+	time.Sleep(100 * time.Millisecond) // Allow sever goroutine to start
+
+	testPort, err := srv.GetPort()
+	wt.AssertNoErr(t, err)
+	wt.AssertNotEqualInt(t, testPort, 0, "listen port")
+
+	Debug.Printf("Adding an IPs to %s", testName1)
+	dbs[1].Zone.AddRecord(containerID, testName1, net.ParseIP("10.2.2.1"))
+
+	// Zone database #2 at this point:
+	//   first.weave.local  = 10.2.2.1
+
+	// testName1 and testName2 should have no IPs yet
+	qName1, _ := assertExchange(t, testName1, dns.TypeA, testPort, 1, 1, 0)
+	qName2, _ := assertExchange(t, testName2, dns.TypeA, testPort, 0, 0, dns.RcodeNameError)
+	assertInCache(t, cache, qName1, "after asking for first name")
+	assertNotLocalInCache(t, cache, qName2, "after asking for second name")
+
+	forwardClock(refreshInterval / 2)
+
+	Debug.Printf("Adding an IP to %s and to %s", testName1, testName2)
+	dbs[1].Zone.AddRecord(containerID, testName1, net.ParseIP("10.2.2.2"))
+	dbs[1].Zone.AddRecord(containerID, testName2, net.ParseIP("10.9.9.2"))
+
+	// Zone database #2 at this point:
+	//   first.weave.local    = 10.2.2.1 10.2.2.2
+	//   second.weave.local   = 10.9.9.2
+	forwardClock(refreshInterval/2 + 2)
+
+	// at this point, the testName1 should have been refreshed
+	// so it should have two IPs, and the cache entry should have been invalidated
+	assertNotInCache(t, cache, qName1, fmt.Sprintf("after asking for %s", testName1))
+	assertNotLocalInCache(t, cache, qName2, fmt.Sprintf("after asking for %s", testName2))
+
+	qName1, _ = assertExchange(t, testName1, dns.TypeA, testPort, 2, 2, 0)
+	qName2, _ = assertExchange(t, testName2, dns.TypeA, testPort, 0, 0, dns.RcodeNameError)
+	assertInCache(t, cache, qName1, fmt.Sprintf("after asking for %s", testName1))
+	assertNotLocalInCache(t, cache, qName2, "after asking for a unknown name")
+
+	// delete the IPs, and some time passes by so the cache should be purged...
+	dbs[1].Zone.DeleteRecord(containerID, net.ParseIP("10.2.2.1"))
+	dbs[1].Zone.DeleteRecord(containerID, net.ParseIP("10.2.2.2"))
+	forwardClock(refreshInterval + 1)
+
+	qName1, _ = assertExchange(t, testName1, dns.TypeA, testPort, 0, 0, dns.RcodeNameError)
+	qName2, _ = assertExchange(t, testName2, dns.TypeA, testPort, 0, 0, dns.RcodeNameError)
+	assertNotLocalInCache(t, cache, qName1, "after asking for a unknown name")
+	assertNotLocalInCache(t, cache, qName2, "after asking for a unknown name")
+
+}