test de/serialization; fix bugs

internal/checkpoints/checkpoints.go

@@ -2,7 +2,6 @@ package checkpoints
 
 import (
 	"bufio"
-	"encoding/binary"
 	"fmt"
 	"io"
 	"reflect"
@@ -38,20 +37,16 @@ type Metrics struct {
 }
 
 func (c *Checkpoint) Serialize(w io.Writer) error {
-	// Write magic value (8 byte):
-	if _, err := w.Write([]byte(magicValue)); err != nil {
-		return err
-	}
-
 	// The header:
 	buf := make([]byte, 0, writeBufferSize*2)
+	buf = append(buf, magicValue...)
 	buf = encodeBytes(buf, c.Reserved)
 	buf = encodeUint64(buf, c.From)
 	buf = encodeUint64(buf, c.To)
 
 	// The rest:
-	buf, err := c.Root.serialize(w, buf)
-	if err != nil {
+	var err error
+	if buf, err = c.Root.serialize(w, buf); err != nil {
 		return err
 	}
 
@@ -99,7 +94,7 @@ func (c *CheckpointLevel) serialize(w io.Writer, buf []byte) ([]byte, error) {
 }
 
 func (m *Metrics) serialize(w io.Writer, buf []byte) ([]byte, error) {
-	buf = encodeBytes(m.Reserved, buf)           // Reserved
+	buf = encodeBytes(buf, m.Reserved)           // Reserved
 	buf = encodeUint64(buf, m.Frequency)         // Frequency
 	buf = encodeUint64(buf, m.From)              // First measurmenet timestamp
 	buf = encodeUint32(buf, uint32(len(m.Data))) // Number of elements
@@ -114,7 +109,7 @@ func (m *Metrics) serialize(w io.Writer, buf []byte) ([]byte, error) {
 }
 
 func (c *Checkpoint) Deserialize(r *bufio.Reader) error {
-	buf := make([]byte, 8, 16384)
+	buf := make([]byte, len(magicValue), 16384)
 	if _, err := io.ReadFull(r, buf); err != nil {
 		return err
 	}
@@ -151,40 +146,46 @@ func (c *CheckpointLevel) deserialize(buf []byte, r *bufio.Reader) error {
 	if err != nil {
 		return err
 	}
+	if n != 0 {
 		c.Metrics = make(map[string]*Metrics, n)
 		for i := 0; i < int(n); i++ {
 			key, err := decodeString(buf, r)
 			if err != nil {
-			return err
+				return fmt.Errorf("decoding metric key: %w", err)
 			}
 
+			// log.Printf("decoding metric %#v...\n", key)
 			metrics := &Metrics{}
 			if err := metrics.deserialize(buf, r); err != nil {
-			return err
+				return fmt.Errorf("decoding metric for key %#v: %w", key, err)
 			}
 
 			c.Metrics[key] = metrics
 		}
+	}
 
 	// Sublevels:
 	n, err = decodeUint32(buf, r)
 	if err != nil {
 		return err
 	}
+	if n != 0 {
 		c.Sublevels = make(map[string]*CheckpointLevel, n)
 		for i := 0; i < int(n); i++ {
 			key, err := decodeString(buf, r)
 			if err != nil {
-			return err
+				return fmt.Errorf("decoding sublevel key: %w", err)
 			}
 
+			// log.Printf("decoding sublevel %#v...\n", key)
 			sublevel := &CheckpointLevel{}
 			if err := sublevel.deserialize(buf, r); err != nil {
-			return err
+				return fmt.Errorf("decoding sublevel for key %#v: %w", key, err)
 			}
 
 			c.Sublevels[key] = sublevel
 		}
+	}
 
 	return nil
 }
@@ -212,7 +213,7 @@ func (m *Metrics) deserialize(buf []byte, r *bufio.Reader) error {
 	elmsize := unsafe.Sizeof(x)
 	bytes = memstore.RequestBytes(int(n) * int(elmsize))
 	if _, err := io.ReadFull(r, bytes); err != nil {
-		return err
+		return fmt.Errorf("reading payload (n=%d, elmsize=%d): %w", n, elmsize, err)
 	}
 
 	sh := (*reflect.SliceHeader)(unsafe.Pointer(&bytes))
@@ -222,26 +223,32 @@ func (m *Metrics) deserialize(buf []byte, r *bufio.Reader) error {
 
 func encodeBytes(buf []byte, bytes []byte) []byte {
 	buf = encodeUint32(buf, uint32(len(bytes)))
-	buf = append(buf, bytes...)
-	return buf
+	return append(buf, bytes...)
 }
 
 func encodeString(buf []byte, str string) []byte {
 	buf = encodeUint32(buf, uint32(len(str)))
-	buf = append(buf, str...)
-	return buf
+	return append(buf, str...)
 }
 
 func encodeUint64(buf []byte, i uint64) []byte {
-	buf = append(buf, 0, 0, 0, 0, 0, 0, 0, 0) // 8 bytes
-	binary.LittleEndian.PutUint64(buf, i)
-	return buf[8:]
+	return append(buf,
+		byte((i>>0)&0xff),
+		byte((i>>8)&0xff),
+		byte((i>>16)&0xff),
+		byte((i>>24)&0xff),
+		byte((i>>32)&0xff),
+		byte((i>>40)&0xff),
+		byte((i>>48)&0xff),
+		byte((i>>56)&0xff))
 }
 
 func encodeUint32(buf []byte, i uint32) []byte {
-	buf = append(buf, 0, 0, 0, 0) // 4 bytes
-	binary.LittleEndian.PutUint32(buf, i)
-	return buf[4:]
+	return append(buf,
+		byte((i>>0)&0xff),
+		byte((i>>8)&0xff),
+		byte((i>>16)&0xff),
+		byte((i>>24)&0xff))
 }
 
 func decodeBytes(buf []byte, r *bufio.Reader) ([]byte, error) {
@@ -250,9 +257,13 @@ func decodeBytes(buf []byte, r *bufio.Reader) ([]byte, error) {
 		return nil, err
 	}
 
+	if len == 0 {
+		return nil, nil
+	}
+
 	bytes := make([]byte, len)
 	if _, err := io.ReadFull(r, bytes); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("decoding %d bytes: %w", len, err)
 	}
 	return bytes, nil
 }
@@ -283,7 +294,14 @@ func decodeUint64(buf []byte, r *bufio.Reader) (uint64, error) {
 		return 0, err
 	}
 
-	return binary.LittleEndian.Uint64(buf), nil
+	return (uint64(buf[0]) << 0) |
+		(uint64(buf[1]) << 8) |
+		(uint64(buf[2]) << 16) |
+		(uint64(buf[3]) << 24) |
+		(uint64(buf[4]) << 32) |
+		(uint64(buf[5]) << 40) |
+		(uint64(buf[6]) << 48) |
+		(uint64(buf[7]) << 56), nil
 }
 
 func decodeUint32(buf []byte, r *bufio.Reader) (uint32, error) {
@@ -293,5 +311,8 @@ func decodeUint32(buf []byte, r *bufio.Reader) (uint32, error) {
 		return 0, err
 	}
 
-	return binary.LittleEndian.Uint32(buf), nil
+	return (uint32(buf[0]) << 0) |
+		(uint32(buf[1]) << 8) |
+		(uint32(buf[2]) << 16) |
+		(uint32(buf[3]) << 24), nil
 }

internal/checkpoints/checkpoints_test.go

@@ -0,0 +1,109 @@
+package checkpoints
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"log"
+	"reflect"
+	"testing"
+
+	"github.com/ClusterCockpit/cc-metric-store/internal/types"
+)
+
+func TestIntEncoding(t *testing.T) {
+	buf := make([]byte, 0, 100)
+	x1 := uint64(0x0102030405060708)
+	buf = encodeUint64(buf, x1)
+
+	x2, err := decodeUint64(make([]byte, 0, 10), bufio.NewReader(bytes.NewReader(buf)))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if x1 != x2 {
+		t.Fatalf("uint64: x1 != x2: %x != %x", x1, x2)
+	}
+
+	buf = buf[0:0:100]
+	x3 := uint32(0xabcde)
+	buf = encodeUint32(buf, x3)
+
+	x4, err := decodeUint32(make([]byte, 0, 10), bufio.NewReader(bytes.NewReader(buf)))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if x3 != x4 {
+		t.Fatalf("uint32: x3 != x4: %x != %x", x3, x4)
+	}
+}
+
+func TestIdentity(t *testing.T) {
+	input := &Checkpoint{
+		Reserved: []byte("Hallo Welt"),
+		From:     1234,
+		To:       5678,
+		Root: &CheckpointLevel{
+			Reserved: nil,
+			Sublevels: map[string]*CheckpointLevel{
+				"host1": {
+					Reserved: []byte("some text..."),
+					Metrics: map[string]*Metrics{
+						"flops": {
+							Reserved:  []byte("blablabla"),
+							Frequency: 60,
+							From:      12345,
+							Data:      []types.Float{1.1, 2.2, 3.3, 4.4, 5.5, 6.6},
+						},
+						"xyz": {
+							Frequency: 10,
+							From:      123,
+							Data:      []types.Float{1.2, 3.4, 5.6, 7.8},
+						},
+					},
+				},
+				"host2": {
+					Sublevels: map[string]*CheckpointLevel{
+						"cpu0": {
+							Metrics: map[string]*Metrics{
+								"abc": {
+									Frequency: 42,
+									From:      420,
+									Data:      []types.Float{1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., 12., 13., 14., 15.},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	disk := &bytes.Buffer{}
+	if err := input.Serialize(disk); err != nil {
+		t.Fatal("serialization failed:", err)
+	}
+
+	// fmt.Printf("disk.Len() = %d\n", disk.Len())
+	// fmt.Printf("disk.Bytes() = %#v", disk.Bytes())
+
+	output := &Checkpoint{}
+	if err := output.Deserialize(bufio.NewReader(disk)); err != nil {
+		t.Fatal("deserialization failed:", err)
+	}
+
+	if !reflect.DeepEqual(input, output) {
+		input_json, err := json.Marshal(input)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		output_json, err := json.Marshal(output)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		log.Printf("a: %#v", string(input_json))
+		log.Printf("b: %#v", string(output_json))
+		t.Fatal("x != deserialize(serialize(x))")
+	}
+}