fs_db

README

FS DB

FS DB is a simple key-value database for storing files. FS DB has two clients that give you the option to inline database logic into your application or run an external server and send data using grpc.

Install

go get -u github.com/glebziz/fs_db

Usage

Store interface

FS DB provides the following store key-value interface:

type Store interface {
	// Set sets the contents of b using the key. 
	Set(ctx context.Context, key string, b []byte) error

	// SetReader sets the reader content using the key. 
	SetReader(ctx context.Context, key string, reader io.Reader) error

	// Get returns content by key. 
	Get(ctx context.Context, key string) ([]byte, error)

	// GetReader returns content as io.ReadCloser by key. 
	GetReader(ctx context.Context, key string) (io.ReadCloser, error)

	// GetKeys returns all keys from the database. 
	GetKeys(ctx context.Context) ([]string, error)

	// Delete delete content by key. 
	Delete(ctx context.Context, key string) error
	
	// Create returns the File for to write to.
	Create(ctx context.Context, key string) (File, error)
}

Transaction interface

FS DB provides the following transaction interface:

type TxOps interface {
	// Commit commits the transaction. 
	Commit(ctx context.Context) error

	// Rollback rolls back the transaction. 
	Rollback(ctx context.Context) error
}

DB interface

FS DB provides the following client interface:

type DB interface {
	Store

	// Begin starts a transaction with isoLevel. 
	Begin(ctx context.Context, isoLevel ...model.TxIsoLevel) (Tx, error)
	
	// Close closed the connection to fs_db. 
	Close() error
}

The database client supports starting a transaction with four standard isolation levels:

• ReadUncommitted
• ReadCommitted
• RepeatableRead
• Serializable

Since the set operation contains insert and update operations, the serializable level is equal to the repeatable read.

Use the following constants to select the isolation level:

const (
	IsoLevelReadUncommitted
	IsoLevelReadCommitted
	IsoLevelRepeatableRead
	IsoLevelSerializable
)

Tx interface

FS DB provides the following tx interface:

type Tx interface {
	TxOps
	Store
}

Example

See more examples here.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/glebziz/fs_db/config"
	"github.com/glebziz/fs_db/pkg/inline"
)

func main() {
	db, err := inline.Open(context.Background(), config.Config{
		Storage: config.Storage{
			DbPath:      "test_db",
			MaxDirCount: 1,
			RootDirs:    []string{"./testStorage"},
			GCPeriod:    1 * time.Minute,
		},
		WPool: config.WPool{
			NumWorkers:   runtime.GOMAXPROCS(0),
			SendDuration: 1 * time.Millisecond,
		},
	})
	if err != nil {
		log.Fatalln("Open db inline:", err)
	}
	defer db.Close()

	err = db.Set(context.Background(), "someKey", []byte("some content"))
	if err != nil {
		log.Panicln("Set:", err)
	}

	b, err := db.Get(context.Background(), "someKey")
	if err != nil {
		log.Panicln("Get:", err)
	}

	fmt.Println(string(b))
}

License

MIT

Documentation

Overview

Package fs_db provides a client for a simple key-value database for storing files.

Index

• Constants
• Variables
• type DB
• type File
• type Store
• type Tx
  • func CreateTx(store Store, t TxOps, ctxFn txCtxFn) Tx
• type TxOps

Constants

const (
	// IsoLevelReadUncommitted transaction iso level read uncommitted.
	IsoLevelReadUncommitted = model.TxIsoLevel(iota)

	// IsoLevelReadCommitted transaction iso level read committed.
	IsoLevelReadCommitted

	// IsoLevelRepeatableRead transaction iso level repeatable read.
	IsoLevelRepeatableRead

	// IsoLevelSerializable transaction iso level serializable.
	//
	// Since the set operation contains insert and update operations,
	// the serializable level is equal to the repeatable read.
	IsoLevelSerializable
)

const (
	// IsoLevelDefault the default transaction iso level is ReadCommitted.
	IsoLevelDefault = IsoLevelReadCommitted
)

Variables

var (
	ErrUnknown = errors.New("unknown error")

	ErrNoFreeSpace    = errors.New("no free space")
	ErrNotFound       = errors.New("not found")
	ErrEmptyKey       = errors.New("empty key")
	ErrHeaderNotFound = errors.New("header not found")

	// Tx errors.
	ErrTxNotFound      = errors.New("transaction not found")
	ErrTxAlreadyExists = errors.New("transaction already exists")
	ErrTxSerialization = errors.New("serialization error")

	// Config errors.
	ErrEmptyDbPath   = errors.New("empty db path")
	ErrEmptyRootDirs = errors.New("empty root dirs")
)

var (
	SizeErr           = ErrNoFreeSpace
	NotFoundErr       = ErrNotFound
	EmptyKeyErr       = ErrEmptyKey
	HeaderNotFoundErr = ErrHeaderNotFound

	// Tx errors.
	TxNotFoundErr      = ErrTxNotFound
	TxAlreadyExistsErr = ErrTxAlreadyExists
	TxSerializationErr = ErrTxSerialization

	// Config errors.
	EmptyDbPathErr = ErrEmptyDbPath
	EmptyRootDirs  = ErrEmptyRootDirs
)

Old errors to maintain backward compatibility.

Types

type DB

type DB interface {
	Store

	// Begin starts a transaction with isoLevel.
	Begin(ctx context.Context, isoLevel ...model.TxIsoLevel) (Tx, error)

	// Close closed the connection to fs_db.
	Close() error
}

DB provides fs db interface.

type File

type File interface {
	io.WriteCloser
}

type Store

type Store interface {
	// Set sets the contents of b using the key.
	Set(ctx context.Context, key string, b []byte) error

	// SetReader sets the reader content using the key.
	SetReader(ctx context.Context, key string, reader io.Reader) error

	// Get returns content by key.
	Get(ctx context.Context, key string) ([]byte, error)

	// GetReader returns content as io.ReadCloser by key.
	GetReader(ctx context.Context, key string) (io.ReadCloser, error)

	// GetKeys returns all keys from the database.
	GetKeys(ctx context.Context) ([]string, error)

	// Delete delete content by key.
	Delete(ctx context.Context, key string) error

	// Create returns the File for to write to.
	Create(ctx context.Context, key string) (File, error)
}

Store provides KV operations with files.

type Tx

type Tx interface {
	TxOps
	Store
}

Tx provides fs db transaction interface.

func CreateTx

func CreateTx(store Store, t TxOps, ctxFn txCtxFn) Tx

CreateTx returns transaction fs db.

type TxOps

type TxOps interface {
	// Commit commits the transaction.
	Commit(ctx context.Context) error

	// Rollback rolls back the transaction.
	Rollback(ctx context.Context) error
}

TxOps provides transactional operations.