README
¶
KVDB
A tree like structure key value database powered by SQLite, LevelDB, MongoDB etc
Getting Started
Simple local usage
// Create A KVDB instance using RDB or LevelDB backend
db, err := rdb.NewDB(rdb.DriverSqlite3, "sqlite.db")
if err != nil {
panic(err)
}
// Use this instance for `Get/Set/Delete/...` operations
err = db.Set("k", "v")
if err != nil {
panic(err)
}
rst, err := db.Get("k")
if err != nil {
panic(err)
}
fmt.Println("value is:", rst.Value) // should be v
Service usage
Some DB like SQLite and LevelDB does not provide a server for remote connect, which means unavailable for a common data source for distributed services. KVDB provide a service layer so you can easily use it in other process or a remote program.
- Server side
db, err := rdb.NewDB(rdb.DriverSqlite3, "sqlite.db")
if err != nil {
panic(err)
}
// this line will block your goroutine and start serving KVDB by provided
// network and address
err = server.StartServer(db, "tcp", ":9090")
if err != nil {
panic(err)
}
- Client side
db, err := service.DialKVDBService("tcp", ":9090")
if err != nil {
panic(err)
}
// just use db like local KVDB instance, for example
err = db.Set("k", "v")
if err != nil {
panic(err)
}
rst, err := db.Get("k")
if err != nil {
panic(err)
}
fmt.Println("value is:", rst.Value) // should be v
Tree like structure
KVDB treat key also as path of key tree, for example, for a key tree like this:
a
|
/ \
b1 b2
| |
/ \ / \
c1 c2 c3 c4
Should use follow keys:
a
a.b1
a.b2
a.b1.c1
a.b1.c2
a.b2.c3
a.b2.c4
Then when using Get/GetMulti, you can also retrieve children (not grand children) key-values
rst, err := db.Get("a", kvdb.GetChildren("", 2))
if err != nil {
panic(err)
}
fmt.Println("length of children of result:", len(rst.Children)) // should be 2
for k, v := range rst.Children {
fmt.Printf("Child key: %s, value: %s", k, v)
// should ouput a.b1 and a.b2 with it's value
}
TTL
KVDB support time to live for key, you can set expire time when using Set/SetMulti
err = db.Set("k", "v", kvdb.SetExpire(time.Now()))
if err != nil {
panic(err)
}
time.Sleep(time.Second)
rst, err := db.Get("k")
if err != nil {
panic(err)
}
fmt.Println("result is:", rst) // should be nil
KVDB would not delete expired key-value data until you called Cleanup. Or you can enable auto cleanup, which will cleanup periodically.
rdb.NewDB(rdb.DriverSqlite3, "sqlite.db", kvdb.AutoClean())
License
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
var (
ErrorKeyValuePairs = errors.New("invalid key value pairs")
)
Functions ¶
This section is empty.
Types ¶
type DBOption ¶
type DBOption func(d *Option)
func DefaultLimit ¶
DefaultLimit specify default limit of children pagination for DB.
func KeyPathSep ¶
KeyPathSep specify separater of key path for DB, default is ".".
type DeleteOption ¶
type DeleteOption func(d *Deleter)
func DeleteChildren ¶
func DeleteChildren() DeleteOption
DeleteChildren specify to delete children for `Delete()` or `DeleteMulti()`.
type GetOption ¶
type GetOption func(g *Getter)
func GetChildren ¶
GetChildren specify to get children and set children pagination for `Get()` or `GetMulti()`. Start is the start key of children, could be full key or bare key, if using for `GetMulti()` to get children of every key, should use bare key for start. Limit is the maximum count of children of every key.
type KVDB ¶
type KVDB interface {
// Get get node of key, which include value and optional children key value
// pairs with pagination.
Get(key string, opts ...GetOption) (*Node, error)
// GetMulti get node map of keys, which include value and optional children
// key value pairs with pagination of every key.
GetMulti(keys []string, opts ...GetOption) (map[string]Node, error)
// Set set value for key with options, which you can specify expire time of
// key.
Set(key, value string, opts ...SetOption) error
// SetMulti set key value pairs with options, which you can specify expire
// time of keys.
// For example, SetMulti([]string{"a", 1, "b", 2}) means set value 1 for key
// a and set value 2 for key b.
SetMulti(kvPairs []string, opts ...SetOption) error
// Delete delete key with options, which you can specify also delete
// children of this key.
// Delete would not effect on any other keys, for example, if you delete the
// key without any option, you can still use it's child keys or parent key.
Delete(key string, opts ...DeleteOption) error
// DeleteMulti delete keys with options, which you can specify also delete
// children of these keys.
// DeleteMulti would not effect on any other keys, for example, if you
// delete the key without any option, you can still use it's child keys or
// parent key.
DeleteMulti(keys []string, opts ...DeleteOption) error
// Exist check if key is exist.
Exist(key string) (bool, error)
// Cleanup delete all expired keys from DB.
Cleanup() error
// Close close DB. should only execute once and cannot use after close.
Close() error
}
Source Files
Directories