Testing and fixing the file snapshots

file_snapshot.go

@@ -72,7 +72,13 @@ func NewFileSnapshotStore(base string, retain int) (*FileSnapshotStore, error) {
 		return nil, fmt.Errorf("must retain at least one snapshot")
 	}
 
+	// Ensure our path exists
 	path := filepath.Join(base, snapPath)
+	if err := os.Mkdir(path, 0755); err != nil && !os.IsExist(err) {
+		return nil, fmt.Errorf("snapshot path not accessible: %v", err)
+	}
+
+	// Setup the store
 	store := &FileSnapshotStore{
 		path:   path,
 		retain: retain,
@@ -93,14 +99,15 @@ func (f *FileSnapshotStore) testPermissions() error {
 		return err
 	}
 	fh.Close()
+	os.Remove(path)
 	return nil
 }
 
 // Create is used to start a new snapshot
 func (f *FileSnapshotStore) Create(index, term uint64, peers []byte) (SnapshotSink, error) {
 	// Create a new path
-	name := time.Now().Format(time.RFC3339) + tmpSuffix
-	path := filepath.Join(f.path, name)
+	name := time.Now().Format(time.RFC3339)
+	path := filepath.Join(f.path, name+tmpSuffix)
 	log.Printf("[INFO] Creating new snapshot at %s", path)
 
 	// Make the directory
@@ -115,7 +122,7 @@ func (f *FileSnapshotStore) Create(index, term uint64, peers []byte) (SnapshotSi
 		dir:   path,
 		meta: fileSnapshotMeta{
 			SnapshotMeta: SnapshotMeta{
-				ID:    path,
+				ID:    name,
 				Index: index,
 				Term:  term,
 				Peers: peers,
@@ -179,14 +186,15 @@ func (f *FileSnapshotStore) getSnapshots() ([]*fileSnapshotMeta, error) {
 
 	// Populate the metadata, reverse order (newest first)
 	var snapMeta []*fileSnapshotMeta
-	for i := len(snapshots) - 1; i >= 0; i++ {
+	for i := len(snapshots); i > 0; i-- {
 		// Ignore any files
-		if !snapshots[i].IsDir() {
+		snap := snapshots[i-1]
+		if !snap.IsDir() {
 			continue
 		}
 
 		// Ignore any temporary snapshots
-		dirName := snapshots[i].Name()
+		dirName := snap.Name()
 		if strings.HasSuffix(dirName, tmpSuffix) {
 			log.Printf("[WARN] Found temporary snapshot: %v", dirName)
 			continue

file_snapshot_test.go

@@ -0,0 +1,122 @@
+package raft
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestFileSnapshotStoreImpl(t *testing.T) {
+	var impl interface{} = &FileSnapshotStore{}
+	if _, ok := impl.(SnapshotStore); !ok {
+		t.Fatalf("FileSnapshotStore not a SnapshotStore")
+	}
+}
+
+func TestFileSnapshotSinkImpl(t *testing.T) {
+	var impl interface{} = &FileSnapshotSink{}
+	if _, ok := impl.(SnapshotSink); !ok {
+		t.Fatalf("FileSnapshotSink not a SnapshotSink")
+	}
+}
+
+func TestFileSS_CreateSnapshot(t *testing.T) {
+	// Create a test dir
+	dir, err := ioutil.TempDir("", "raft")
+	if err != nil {
+		t.Fatalf("err: %v ", err)
+	}
+	defer os.RemoveAll(dir)
+
+	snap, err := NewFileSnapshotStore(dir, 3)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Check no snapshots
+	snaps, err := snap.List()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if len(snaps) != 0 {
+		t.Fatalf("did not expect any snapshots: %v", snaps)
+	}
+
+	// Create a new sink
+	peers := []byte("all my lovely friends")
+	sink, err := snap.Create(10, 3, peers)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// The sink is not done, should not be in a list!
+	snaps, err = snap.List()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if len(snaps) != 0 {
+		t.Fatalf("did not expect any snapshots: %v", snaps)
+	}
+
+	// Write to the sink
+	_, err = sink.Write([]byte("first\n"))
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	_, err = sink.Write([]byte("second\n"))
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Done!
+	err = sink.Close()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Should have a snapshot!
+	snaps, err = snap.List()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if len(snaps) != 1 {
+		t.Fatalf("expect a snapshots: %v", snaps)
+	}
+
+	// Check the latest
+	latest := snaps[0]
+	if latest.Index != 10 {
+		t.Fatalf("bad snapshot: %v", *latest)
+	}
+	if latest.Term != 3 {
+		t.Fatalf("bad snapshot: %v", *latest)
+	}
+	if bytes.Compare(latest.Peers, peers) != 0 {
+		t.Fatalf("bad snapshot: %v", *latest)
+	}
+	if latest.Size != 13 {
+		t.Fatalf("bad snapshot: %v", *latest)
+	}
+
+	// Read the snapshot
+	r, err := snap.Open(latest.ID)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Read out everything
+	var buf bytes.Buffer
+	if _, err := io.Copy(&buf, r); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if err := r.Close(); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Ensure a match
+	if bytes.Compare(buf.Bytes(), []byte("first\nsecond\n")) != 0 {
+		t.Fatalf("content mismatch")
+	}
+}