Reload zone when a write is detected (#122)

Zone reloading

middleware/file/reload_test.go

@@ -0,0 +1,62 @@
+package file
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/miekg/coredns/middleware/test"
+	"github.com/miekg/dns"
+)
+
+func TestZoneReload(t *testing.T) {
+	fileName, rm, err := test.Zone(t, ".", reloadZoneTest)
+	if err != nil {
+		t.Fatalf("failed to create zone: %s", err)
+	}
+	defer rm()
+	reader, err := os.Open(fileName)
+	if err != nil {
+		t.Fatalf("failed to open zone: %s", err)
+	}
+	z, err := Parse(reader, "miek.nl", fileName)
+	if err != nil {
+		t.Fatalf("failed to parse zone: %s", err)
+	}
+
+	z.Reload(nil)
+
+	if _, _, _, res := z.Lookup("miek.nl.", dns.TypeSOA, false); res != Success {
+		t.Fatalf("failed to lookup, got %d", res)
+	}
+
+	if _, _, _, res := z.Lookup("miek.nl.", dns.TypeNS, false); res != Success {
+		t.Fatalf("failed to lookup, got %d", res)
+	}
+
+	if len(z.All()) != 5 {
+		t.Fatalf("expected 5 RRs, got %d", len(z.All()))
+	}
+	if err := ioutil.WriteFile(fileName, []byte(reloadZone2Test), 0644); err != nil {
+		t.Fatalf("failed to write new zone data", err)
+	}
+	// Could still be racy, but we need to wait a bit for the event to be seen
+	time.Sleep(1 * time.Second)
+
+	if len(z.All()) != 3 {
+		t.Fatalf("expected 3 RRs, got %d", len(z.All()))
+	}
+}
+
+const reloadZoneTest = `miek.nl.		1627	IN	SOA	linode.atoom.net. miek.miek.nl. 1460175181 14400 3600 604800 14400
+miek.nl.		1627	IN	NS	ext.ns.whyscream.net.
+miek.nl.		1627	IN	NS	omval.tednet.nl.
+miek.nl.		1627	IN	NS	linode.atoom.net.
+miek.nl.		1627	IN	NS	ns-ext.nlnetlabs.nl.
+`
+
+const reloadZone2Test = `miek.nl.		1627	IN	SOA	linode.atoom.net. miek.miek.nl. 1460175181 14400 3600 604800 14400
+miek.nl.		1627	IN	NS	ext.ns.whyscream.net.
+miek.nl.		1627	IN	NS	omval.tednet.nl.
+`