README
¶
clerk 
Package clerk provides file persistence for your Go structures.
This can replace external databases for small projects that can keep data in memory and do few writes.
Installing
-
Get package:
go get -u github.com/arthurwhite/clerk -
Import it in your code:
import "github.com/arthurwhite/clerk"
Usage
Init
Make a new database structure by embedding DB and initiate it with the destination file name used on saving.
Only exported fields can be saved.
Use DB.Rebase to retreive the data from an existent file at startup.
var db = new(struct {
clerk.DB
Data interface{}
})
func init() {
clerk.Init("data.gob", db)
if err := db.Rebase(); err != nil {
panic(err)
}
}
Modification
DB embeds a sync.RWMutex that should be used when accessing the data from multiple goroutines.
db.Lock()
defer db.Unlock()
db.Data = "one"
Saving
After a data change and while the concurrent access is still locked, use DB.Save to encode the source with gob and save it in the destination file:
if err := db.Save(); err != nil {
panic(err)
}
Documentation
¶
Overview ¶
Package clerk provides file persistence for your Go structures.
It can replace external databases for small projects that can keep data in memory and don't make a lot of writes.
Example ¶
package main
import "github.com/arthurwhite/clerk"
type User struct {
Name string
}
var db = new(struct {
clerk.DB
Users []*User
})
func init() {
clerk.Init("example.gob", db)
}
func main() {
db.Lock()
defer db.Unlock()
db.Users = append(db.Users, &User{"Crowe"}, &User{"Jones"}, &User{"Owen"})
if err := db.Save(); err != nil {
panic(err)
}
}
Index ¶
- Variables
- func Init(filename string, db DBInterface)
- type DB
- func (db *DB) Lock()
- func (db *DB) Migrate(timestamp string, oldDB DBInterface, do func() error) error
- func (db *DB) MigrateOrRebase(timestamp string, oldDB DBInterface, do func() error)
- func (db *DB) RLock()
- func (db *DB) RUnlock()
- func (db *DB) Rebase() error
- func (db *DB) Remove() error
- func (db *DB) Save() error
- func (db *DB) Touch()
- func (db *DB) Unlock()
- type DBInterface
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var ( ErrDBInited = errors.New("clerk: database inited multiple times") ErrDBNotInited = errors.New("clerk: database not inited") ErrOldMigration = errors.New("clerk: database in file is newer than migration timestamp") )
Errors.
Functions ¶
Types ¶
type DB ¶
type DB struct {
UpdatedAt time.Time // UpdatedAt is the timestamp of the last data modification (by calling DB.Lock).
// contains filtered or unexported fields
}
DB provides methods to persist your data.
func (*DB) Migrate ¶
func (db *DB) Migrate(timestamp string, oldDB DBInterface, do func() error) error
Migrate runs a migration if provided date is after the one registered in the data file. It rebases the database file in oldDB, runs function do and saves database. timestamp format is:
2006-01-02 15:04:05 -07
func (*DB) MigrateOrRebase ¶
func (db *DB) MigrateOrRebase(timestamp string, oldDB DBInterface, do func() error)
MigrateOrRebase runs Migrate. If the migration has not been used, database is rebased. It panics on error.
func (*DB) Rebase ¶
Rebase replaces the data with the content of the file set on init. Be sure the database is locked for writing.
type DBInterface ¶
type DBInterface interface {
Touch()
Save() error
Migrate(string, DBInterface, func() error) error
MigrateOrRebase(string, DBInterface, func() error)
Rebase() error
Remove() error
Lock()
RLock()
Unlock()
RUnlock()
// contains filtered or unexported methods
}
DBInterface represents an underlying database.
Source Files