From 93491791d599d77cdd34c12541e8a598d0bfe863 Mon Sep 17 00:00:00 2001
From: siddontang <siddontang@gmail.com>
Date: Wed, 28 May 2014 14:20:45 +0800
Subject: [PATCH] add dump and load

---
 ledis/dump.go      | 158 +++++++++++++++++++++++++++++++++++++++++++++
 ledis/dump_test.go |  74 +++++++++++++++++++++
 2 files changed, 232 insertions(+)
 create mode 100644 ledis/dump.go
 create mode 100644 ledis/dump_test.go

diff --git a/ledis/dump.go b/ledis/dump.go
new file mode 100644
index 0000000..546ef31
--- /dev/null
+++ b/ledis/dump.go
@@ -0,0 +1,158 @@
+package ledis
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
+	"encoding/json"
+	"github.com/siddontang/go-leveldb/leveldb"
+	"io"
+	"os"
+)
+
+//dump format
+// head len(bigendian int32)|head(json format)
+// |keylen(bigendian int32)|key|valuelen(bigendian int32)|value......
+
+type DumpHead struct {
+	LogFile string `json:"bin_log_file"`
+	LogPos  int64  `json:"bin_log_pos"`
+}
+
+func (l *Ledis) DumpFile(path string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	return l.Dump(f)
+}
+
+func (l *Ledis) Dump(w io.Writer) error {
+	var sp *leveldb.Snapshot
+	var logFileName string
+	var logPos int64
+	if l.binlog == nil {
+		sp = l.ldb.NewSnapshot()
+	} else {
+		l.binlog.Lock()
+		sp = l.ldb.NewSnapshot()
+		logFileName = l.binlog.LogFileName()
+		logPos = l.binlog.LogFilePos()
+		l.binlog.Unlock()
+	}
+
+	var head = DumpHead{
+		LogFile: logFileName,
+		LogPos:  logPos,
+	}
+
+	data, err := json.Marshal(&head)
+	if err != nil {
+		return err
+	}
+
+	wb := bufio.NewWriterSize(w, 4096)
+	if err = binary.Write(wb, binary.BigEndian, uint32(len(data))); err != nil {
+		return err
+	}
+
+	if _, err = wb.Write(data); err != nil {
+		return err
+	}
+
+	it := sp.Iterator(nil, nil, leveldb.RangeClose, 0, -1)
+	var key []byte
+	var value []byte
+	for ; it.Valid(); it.Next() {
+		key = it.Key()
+		value = it.Value()
+
+		if err = binary.Write(wb, binary.BigEndian, uint16(len(key))); err != nil {
+			return err
+		}
+
+		if _, err = wb.Write(key); err != nil {
+			return err
+		}
+
+		if err = binary.Write(wb, binary.BigEndian, uint32(len(value))); err != nil {
+			return err
+		}
+
+		if _, err = wb.Write(value); err != nil {
+			return err
+		}
+	}
+
+	if err = wb.Flush(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (l *Ledis) LoadDumpFile(path string) (*DumpHead, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return l.LoadDump(f)
+}
+
+func (l *Ledis) LoadDump(r io.Reader) (*DumpHead, error) {
+	rb := bufio.NewReaderSize(r, 4096)
+
+	var headLen uint32
+	err := binary.Read(rb, binary.BigEndian, &headLen)
+	if err != nil {
+		return nil, err
+	}
+
+	buf := make([]byte, headLen)
+	if _, err = io.ReadFull(rb, buf); err != nil {
+		return nil, err
+	}
+
+	var head DumpHead
+	if err = json.Unmarshal(buf, &head); err != nil {
+		return nil, err
+	}
+
+	var keyLen uint16
+	var valueLen uint32
+
+	var keyBuf bytes.Buffer
+	var valueBuf bytes.Buffer
+	for {
+		if err = binary.Read(rb, binary.BigEndian, &keyLen); err != nil && err != io.EOF {
+			return nil, err
+		} else if err == io.EOF {
+			break
+		}
+
+		if _, err = io.CopyN(&keyBuf, rb, int64(keyLen)); err != nil {
+			return nil, err
+		}
+
+		if err = binary.Read(rb, binary.BigEndian, &valueLen); err != nil {
+			return nil, err
+		}
+
+		if _, err = io.CopyN(&valueBuf, rb, int64(valueLen)); err != nil {
+			return nil, err
+		}
+
+		if err = l.ldb.Put(keyBuf.Bytes(), valueBuf.Bytes()); err != nil {
+			return nil, err
+		}
+
+		keyBuf.Reset()
+		valueBuf.Reset()
+	}
+
+	return &head, nil
+}
diff --git a/ledis/dump_test.go b/ledis/dump_test.go
new file mode 100644
index 0000000..b27d8f0
--- /dev/null
+++ b/ledis/dump_test.go
@@ -0,0 +1,74 @@
+package ledis
+
+import (
+	"bytes"
+	"github.com/siddontang/go-leveldb/leveldb"
+	"os"
+	"testing"
+)
+
+func TestDump(t *testing.T) {
+	os.RemoveAll("/tmp/testdb_master")
+	os.RemoveAll("/tmp/testdb_slave")
+	os.Remove("/tmp/testdb.dump")
+
+	var masterConfig = []byte(`
+    {
+        "data_db" : {
+            "path" : "/tmp/testdb_master",
+            "compression":true,
+            "block_size" : 32768,
+            "write_buffer_size" : 2097152,
+            "cache_size" : 20971520
+        }
+    }
+    `)
+
+	master, err := Open(masterConfig)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var slaveConfig = []byte(`
+    {
+        "data_db" : {
+            "path" : "/tmp/testdb_slave",
+            "compression":true,
+            "block_size" : 32768,
+            "write_buffer_size" : 2097152,
+            "cache_size" : 20971520
+        }
+    }
+    `)
+
+	var slave *Ledis
+	if slave, err = Open(slaveConfig); err != nil {
+		t.Fatal(err)
+	}
+
+	db, _ := master.Select(0)
+
+	db.Set([]byte("a"), []byte("1"))
+	db.Set([]byte("b"), []byte("2"))
+	db.Set([]byte("c"), []byte("3"))
+
+	if err := master.DumpFile("/tmp/testdb.dump"); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := slave.LoadDumpFile("/tmp/testdb.dump"); err != nil {
+		t.Fatal(err)
+	}
+
+	it := master.ldb.Iterator(nil, nil, leveldb.RangeClose, 0, -1)
+	for ; it.Valid(); it.Next() {
+		key := it.Key()
+		value := it.Value()
+
+		if v, err := slave.ldb.Get(key); err != nil {
+			t.Fatal(err)
+		} else if !bytes.Equal(v, value) {
+			t.Fatal("load dump error")
+		}
+	}
+}