coredns/plugin/file/reload_test.go

package file

import (
	"context"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"testing/synctest"
	"time"

	"github.com/coredns/coredns/plugin/test"
	"github.com/coredns/coredns/plugin/transfer"
	"github.com/coredns/coredns/request"

	"github.com/miekg/dns"
)

func TestZoneReload(t *testing.T) {
	fileName, rm, err := test.TempFile(".", 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, 0)
	if err != nil {
		t.Fatalf("Failed to parse zone: %s", err)
	}

	z.ReloadInterval = 10 * time.Millisecond
	z.Reload(&transfer.Transfer{})
	time.Sleep(20 * time.Millisecond)

	ctx := context.TODO()
	r := new(dns.Msg)
	r.SetQuestion("miek.nl", dns.TypeSOA)
	state := request.Request{W: &test.ResponseWriter{}, Req: r}
	if _, _, _, res := z.Lookup(ctx, state, "miek.nl."); res != Success {
		t.Fatalf("Failed to lookup, got %d", res)
	}

	r = new(dns.Msg)
	r.SetQuestion("miek.nl", dns.TypeNS)
	state = request.Request{W: &test.ResponseWriter{}, Req: r}
	if _, _, _, res := z.Lookup(ctx, state, "miek.nl."); res != Success {
		t.Fatalf("Failed to lookup, got %d", res)
	}

	rrs, err := z.ApexIfDefined() // all apex records.
	if err != nil {
		t.Fatal(err)
	}
	if len(rrs) != 5 {
		t.Fatalf("Expected 5 RRs, got %d", len(rrs))
	}
	if err := os.WriteFile(fileName, []byte(reloadZone2Test), 0644); err != nil {
		t.Fatalf("Failed to write new zone data: %s", err)
	}
	for start := time.Now(); time.Since(start) < 2*time.Second; {
		rrs, err = z.ApexIfDefined()
		if err != nil {
			t.Fatal(err)
		}
		if len(rrs) == 3 {
			break
		}
		time.Sleep(2 * time.Millisecond)
	}
	if len(rrs) != 3 {
		t.Fatalf("Expected 3 RRs, got %d", len(rrs))
	}
}

func TestZoneReloadSOAChange(t *testing.T) {
	_, err := Parse(strings.NewReader(reloadZoneTest), "miek.nl.", "stdin", 1460175181)
	if err == nil {
		t.Fatalf("Zone should not have been re-parsed")
	}
}

func TestZoneReloadSOAOrigin(t *testing.T) {
	synctest.Test(t, func(t *testing.T) {
		fileName := filepath.Join(t.TempDir(), "db.example.org")
		z, err := Parse(strings.NewReader(dbRelative), "example.org.", fileName, -1)
		if err != nil {
			t.Fatal(err)
		}
		beforeApex, beforeTree := z.snapshot()
		updated := strings.Replace(dbRelative, " 3 3600", " 4 3600", 1)
		updated = strings.Replace(updated, "192.0.2.1", "192.0.2.2", 1)
		invalid := strings.Replace(updated, "@ 500 IN SOA", "child 500 IN SOA", 1)
		if err := os.WriteFile(fileName, []byte(invalid), 0644); err != nil {
			t.Fatal(err)
		}
		z.ReloadInterval = time.Second
		if err := z.Reload(nil); err != nil {
			t.Fatal(err)
		}
		defer z.OnShutdown()

		time.Sleep(2 * time.Second)
		synctest.Wait()
		apex, tree := z.snapshot()
		if apex.SOA != beforeApex.SOA || tree != beforeTree {
			t.Fatal("invalid reload replaced the last valid zone")
		}

		if err := os.WriteFile(fileName, []byte(updated), 0644); err != nil {
			t.Fatal(err)
		}
		time.Sleep(time.Second)
		synctest.Wait()
		apex, tree = z.snapshot()
		if apex.SOA.Hdr.Name != "example.org." || apex.SOA.Serial != 4 || tree == beforeTree {
			t.Fatalf("corrected zone was not reloaded: %v", apex.SOA)
		}
		r := new(dns.Msg)
		r.SetQuestion("foo.example.org.", dns.TypeA)
		state := request.Request{W: &test.ResponseWriter{}, Req: r}
		answer, _, _, result := z.Lookup(context.Background(), state, state.Name())
		if result != Success || len(answer) != 1 || answer[0].String() != "foo.example.org.\t500\tIN\tA\t192.0.2.2" {
			t.Fatalf("expected updated A record, got result %v, answer %v", result, answer)
		}
	})
}

func TestZoneReloadByMtime(t *testing.T) {
	// Test 1: Basic mtime trigger - file modification should trigger reload
	t.Run("BasicMtimeTrigger", func(t *testing.T) {
		z, fileName, cleanup := prepareMtimeZone(t, reloadZoneTest)
		defer cleanup()

		// Wait for initial load to complete
		time.Sleep(20 * time.Millisecond)

		// Verify initial content (5 records)
		rrs, err := z.ApexIfDefined()
		if err != nil {
			t.Fatal(err)
		}
		if len(rrs) != 5 {
			t.Fatalf("Expected 5 initial RRs, got %d", len(rrs))
		}

		// Modify the zone file (this changes mtime)
		if err := os.WriteFile(fileName, []byte(reloadZone2Test), 0644); err != nil {
			t.Fatalf("Failed to write new zone data: %s", err)
		}

		// Poll until reload is observed (fixed sleeps race under -race, esp. on Windows).
		for start := time.Now(); time.Since(start) < 2*time.Second; {
			rrs, err = z.ApexIfDefined()
			if err != nil {
				t.Fatal(err)
			}
			if len(rrs) == 3 {
				break
			}
			time.Sleep(2 * time.Millisecond)
		}
		if len(rrs) != 3 {
			t.Fatalf("Expected 3 RRs after reload, got %d", len(rrs))
		}
	})

	// Test 2: No reload when mtime unchanged
	t.Run("NoReloadWhenMtimeUnchanged", func(t *testing.T) {
		z, _, cleanup := prepareMtimeZone(t, reloadZoneTest)
		defer cleanup()

		// Wait for initial load
		time.Sleep(20 * time.Millisecond)

		// Record initial SOA serial
		initialSerial := z.SOASerialIfDefined()
		if initialSerial == -1 {
			t.Fatal("Failed to get initial SOA serial")
		}

		// Record initial record count
		rrs, err := z.ApexIfDefined()
		if err != nil {
			t.Fatal(err)
		}
		initialCount := len(rrs)

		// Wait for multiple reload intervals WITHOUT modifying the file
		time.Sleep(50 * time.Millisecond)

		// Verify no reload occurred
		currentSerial := z.SOASerialIfDefined()
		if currentSerial != initialSerial {
			t.Fatalf("SOA serial changed unexpectedly: %d -> %d", initialSerial, currentSerial)
		}

		rrs, err = z.ApexIfDefined()
		if err != nil {
			t.Fatal(err)
		}
		if len(rrs) != initialCount {
			t.Fatalf("Record count changed unexpectedly: %d -> %d", initialCount, len(rrs))
		}
	})

	// Test 3: Content verification after reload
	t.Run("ContentVerificationAfterReload", func(t *testing.T) {
		z, fileName, cleanup := prepareMtimeZone(t, reloadZoneTest)
		defer cleanup()

		ctx := context.TODO()

		// Query initial content
		r := new(dns.Msg)
		r.SetQuestion("miek.nl", dns.TypeNS)
		state := request.Request{W: &test.ResponseWriter{}, Req: r}

		records, _, _, res := z.Lookup(ctx, state, "miek.nl.")
		if res != Success {
			t.Fatalf("Failed to lookup initial NS records, got %d", res)
		}

		// Initial zone has 4 NS records
		if len(records) != 4 {
			t.Fatalf("Expected 4 initial NS records, got %d", len(records))
		}

		// Modify to new zone content (only 2 NS records)
		if err := os.WriteFile(fileName, []byte(reloadZone2Test), 0644); err != nil {
			t.Fatalf("Failed to write new zone data: %s", err)
		}

		// Poll until reload is observed (fixed sleeps race under -race, esp. on Windows).
		for start := time.Now(); time.Since(start) < 2*time.Second; {
			records, _, _, res = z.Lookup(ctx, state, "miek.nl.")
			if res != Success {
				t.Fatalf("Failed to lookup reloaded NS records, got %d", res)
			}
			if len(records) == 2 {
				break
			}
			time.Sleep(2 * time.Millisecond)
		}

		// Reloaded zone has 2 NS records
		if len(records) != 2 {
			t.Fatalf("Expected 2 reloaded NS records, got %d", len(records))
		}

		// Verify the actual NS record names match the new zone
		nsNames := make([]string, len(records))
		for i, rr := range records {
			nsNames[i] = rr.(*dns.NS).Ns
		}

		expectedNS := []string{"ext.ns.whyscream.net.", "omval.tednet.nl."}
		for i, expected := range expectedNS {
			if nsNames[i] != expected {
				t.Errorf("Expected NS record %d to be %s, got %s", i, expected, nsNames[i])
			}
		}
	})

	// Test 4: File deleted/missing during reload
	t.Run("FileMissingDuringReload", func(t *testing.T) {
		z, fileName, cleanup := prepareMtimeZone(t, reloadZoneTest)
		defer cleanup()

		// Wait for initial load
		time.Sleep(20 * time.Millisecond)

		// Verify initial content is loaded
		rrs, err := z.ApexIfDefined()
		if err != nil {
			t.Fatal(err)
		}
		initialCount := len(rrs)

		// Delete the zone file
		if err := os.Remove(fileName); err != nil {
			t.Fatalf("Failed to remove zone file: %s", err)
		}

		// Wait for reload interval (reload should fail gracefully)
		time.Sleep(30 * time.Millisecond)

		// Verify zone still serves old content (didn't crash)
		rrs, err = z.ApexIfDefined()
		if err != nil {
			t.Fatal(err)
		}
		if len(rrs) != initialCount {
			t.Fatalf("Zone content changed unexpectedly after file deletion: %d -> %d", initialCount, len(rrs))
		}

		// Verify DNS queries still work
		ctx := context.TODO()
		r := new(dns.Msg)
		r.SetQuestion("miek.nl", dns.TypeSOA)
		state := request.Request{W: &test.ResponseWriter{}, Req: r}

		_, _, _, res := z.Lookup(ctx, state, "miek.nl.")
		if res != Success {
			t.Fatalf("Zone should still serve queries after file deletion, got result %d", res)
		}
	})

	// Test 5: A successful reload advances the mtime baseline.
	t.Run("MtimeBaselineAdvancesAfterReload", func(t *testing.T) {
		z, fileName, cleanup := prepareMtimeZone(t, reloadZoneTest)
		defer cleanup()

		if err := os.WriteFile(fileName, []byte(reloadZone2Test), 0644); err != nil {
			t.Fatalf("Failed to write new zone data: %s", err)
		}

		var rrs []dns.RR
		for start := time.Now(); time.Since(start) < 2*time.Second; {
			var err error
			rrs, err = z.ApexIfDefined()
			if err != nil {
				t.Fatal(err)
			}
			if len(rrs) == 3 {
				break
			}
			time.Sleep(2 * time.Millisecond)
		}
		if len(rrs) != 3 {
			t.Fatalf("Expected 3 RRs after reload, got %d", len(rrs))
		}

		fi, err := os.Stat(fileName)
		if err != nil {
			t.Fatalf("Failed to stat zone: %s", err)
		}
		z.RLock()
		mtime := z.file_mtime
		z.RUnlock()
		if !mtime.Equal(fi.ModTime()) {
			t.Fatalf("file mtime = %s after reload, want %s", mtime, fi.ModTime())
		}
	})
}

// prepareMtimeZone creates a zone with mtime-based reload enabled.
func prepareMtimeZone(t *testing.T, content string) (*Zone, string, func()) {
	t.Helper()
	fileName, rm, err := test.TempFile(".", content)
	if err != nil {
		t.Fatalf("Failed to create zone: %s", err)
	}
	// A rewrite immediately after creating the file can retain the same mtime
	// on filesystems with coarse timestamp resolution. Start with an older
	// mtime so the rewrite is always observable by the reload loop.
	initialMtime := time.Now().Add(-time.Minute)
	if err := os.Chtimes(fileName, initialMtime, initialMtime); err != nil {
		rm()
		t.Fatalf("Failed to set initial zone mtime: %s", err)
	}

	reader, err := os.Open(fileName)
	if err != nil {
		rm()
		t.Fatalf("Failed to open zone: %s", err)
	}
	z, err := Parse(reader, "miek.nl", fileName, 0)
	reader.Close()
	if err != nil {
		rm()
		t.Fatalf("Failed to parse zone: %s", err)
	}

	fi, err := os.Stat(fileName)
	if err != nil {
		rm()
		t.Fatalf("Failed to stat zone: %s", err)
	}

	z.ReloadInterval = 10 * time.Millisecond
	z.ReloadByMtime = true
	// Parse does not set file_mtime unless ReloadByMtime is already enabled.
	// Seed it so the reload loop only opens the file when mtime changes.
	z.file_mtime = fi.ModTime()
	z.Reload(&transfer.Transfer{})

	return z, fileName, func() {
		z.OnShutdown()
		rm()
	}
}

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. 1460175182 14400 3600 604800 14400
miek.nl.		1627	IN	NS	ext.ns.whyscream.net.
miek.nl.		1627	IN	NS	omval.tednet.nl.
`