A simple tool for storing structs in key value based storages.
It does not provide the database.
-
Add it to your project
go get github.com/carlosmpv/persistent
-
Then, implement the
Storager
interface.type exampleStorager struct { db map[string][]byte } // stores a value (v) with a key (k) func (ts *exampleStorager) Save(k, v []byte) error { ts.db[string(k)] = v return nil } // gets the value given a key (k) func (ts *exampleStorager) Load(k []byte) ([]byte, error) { val, ok := ts.db[string(k)] if !ok { return nil, errors.New("value is not stored") } return val, nil }
This is a very simple storager that uses a
map[string][]byte
as database. It could be a redisset
andget
instead on each method.
Persistent variables are wrappers around golang's standard variable types that uses a given storager to save and load its values.
Declaring a persistent variable
str := NewPersistentString("Hello world!")
empty := EmptyPersistentString()
Those are pointers, so to get its value:
... := *str
Persisting a value
err := str.Persist(storager, "key")
if err != nil {
...
}
Restoring a value
err := nStr.Restore(storager, "key")
// *nStr == *str
Structs that contains persistent fields can also be persisted and restored using PersistStruct
and RestoreStruct
Check persistent_test.go
and its test cases to better understand how to use it