rados: add wrapper for rados_ioctx_snap_list() function

Signed-off-by Mudit Agarwal <muagarwa@redhat.com>

rados/snapshot.go

@@ -117,3 +117,35 @@ func (ioctx *IOContext) GetSnapStamp(snapID SnapID) (time.Time, error) {
 		&cTime)
 	return time.Unix(int64(cTime), 0), getError(ret)
 }
+
+// ListSnaps returns a slice containing the SnapIDs of existing pool snapshots.
+//
+// Implements:
+//  int rados_ioctx_snap_list(rados_ioctx_t io, rados_snap_t *snaps, int maxlen)
+func (ioctx *IOContext) ListSnaps() ([]SnapID, error) {
+	if err := ioctx.validate(); err != nil {
+		return nil, err
+	}
+
+	var (
+		snapList []SnapID
+		cLen     C.int
+		err      error
+		ret      C.int
+	)
+	retry.WithSizes(100, 1000, func(maxlen int) retry.Hint {
+		cLen = C.int(maxlen)
+		snapList = make([]SnapID, cLen)
+		ret = C.rados_ioctx_snap_list(
+			ioctx.ioctx,
+			(*C.rados_snap_t)(unsafe.Pointer(&snapList[0])),
+			cLen)
+		err = getErrorIfNegative(ret)
+		return retry.Size(int(cLen)).If(err == errRange)
+	})
+
+	if err != nil {
+		return nil, err
+	}
+	return snapList[:ret], nil
+}

rados/snapshot_test.go

@@ -136,3 +136,54 @@ func (suite *RadosTestSuite) TestSnapshotIDFunctions() {
 		assert.NoError(t, err)
 	})
 }
+
+func (suite *RadosTestSuite) TestListSnapshot() {
+	suite.SetupConnection()
+	ioctx, err := suite.conn.OpenIOContext(suite.pool)
+	require.NoError(suite.T(), err)
+
+	snapName := []string{"snap1", "snap2", "snap3"}
+	err = ioctx.CreateSnap(snapName[0])
+	assert.NoError(suite.T(), err)
+	defer func() {
+		assert.NoError(suite.T(), ioctx.RemoveSnap(snapName[0]))
+	}()
+
+	err = ioctx.CreateSnap(snapName[1])
+	assert.NoError(suite.T(), err)
+	defer func() {
+		assert.NoError(suite.T(), ioctx.RemoveSnap(snapName[1]))
+	}()
+
+	err = ioctx.CreateSnap(snapName[2])
+	assert.NoError(suite.T(), err)
+	defer func() {
+		assert.NoError(suite.T(), ioctx.RemoveSnap(snapName[2]))
+	}()
+
+	suite.T().Run("invalidIOContext", func(t *testing.T) {
+		ioctx := &IOContext{}
+		_, err := ioctx.ListSnaps()
+		assert.Error(t, err)
+		assert.Equal(t, err, ErrInvalidIOContext)
+	})
+
+	snapList, err := ioctx.ListSnaps()
+	assert.NoError(suite.T(), err)
+	assert.NotNil(suite.T(), snapList)
+
+	listLen := len(snapList)
+
+	suite.T().Run("NumberOfSnapshots", func(t *testing.T) {
+		assert.Equal(t, 3, listLen)
+	})
+
+	suite.T().Run("MatchSnapNamesWithID", func(t *testing.T) {
+		for _, id := range snapList[0 : listLen-1] {
+			retName, err := ioctx.GetSnapName(id)
+			assert.NoError(t, err)
+			assert.NotNil(t, retName)
+			assert.Contains(t, snapName, retName)
+		}
+	})
+}