db

package
v0.3.0 Latest Latest
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 Go to latest Published: Dec 7, 2018 License: AGPL-3.0 Imports: 15 Imported by: 0

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Index

Constants

This section is empty.

Variables

View Source 
var (
	// ErrNoSuchKey is returned when Get() was passed a non-existent key
	ErrNoSuchKey = errors.New("This key does not exist")
)

Functions

func CopyKey 

func CopyKey(db Database, src, dst []string) error

CopyKey is a helper method to copy a bunch of keys in `src` to `dst`.

Types

type BadgerDatabase added in v0.2.0 

type BadgerDatabase struct {
	// contains filtered or unexported fields
}

BadgerDatabase is a database implementation based on BadgerDB

func NewBadgerDatabase added in v0.2.0 

func NewBadgerDatabase(path string) (*BadgerDatabase, error)

NewBadgerDatabase creates a new badger database.

func (*BadgerDatabase) Batch added in v0.2.0 

func (db *BadgerDatabase) Batch() Batch

Batch is the badger implementation of Database.Batch

func (*BadgerDatabase) Clear added in v0.2.0 

func (db *BadgerDatabase) Clear(key ...string) error

Clear is the badger implementation of Database.Clear

func (*BadgerDatabase) Close added in v0.2.0 

func (db *BadgerDatabase) Close() error

Close is the badger implementation of Database.Close

func (*BadgerDatabase) Erase added in v0.2.0 

func (db *BadgerDatabase) Erase(key ...string)

Erase is the badger implementation of Database.Erase

func (*BadgerDatabase) Export added in v0.2.0 

func (db *BadgerDatabase) Export(w io.Writer) error

Export is the badger implementation of Database.Export.

func (*BadgerDatabase) Flush added in v0.2.0 

func (db *BadgerDatabase) Flush() error

Flush is the badger implementation of Database.Flush

func (*BadgerDatabase) Get added in v0.2.0 

func (db *BadgerDatabase) Get(key ...string) ([]byte, error)

Get is the badger implementation of Database.Get.

func (*BadgerDatabase) Glob added in v0.2.0 

func (db *BadgerDatabase) Glob(prefix []string) ([][]string, error)

Glob is the badger implementation of Database.Glob

func (*BadgerDatabase) HaveWrites added in v0.2.0 

func (db *BadgerDatabase) HaveWrites() bool

HaveWrites is the badger implementation of Database.HaveWrites

func (*BadgerDatabase) Import added in v0.2.0 

func (db *BadgerDatabase) Import(r io.Reader) error

Import is the badger implementation of Database.Import.

func (*BadgerDatabase) Keys added in v0.2.0 

func (db *BadgerDatabase) Keys(fn func(key []string) error, prefix ...string) error

Keys is the badger implementation of Database.Keys.

func (*BadgerDatabase) Put added in v0.2.0 

func (db *BadgerDatabase) Put(val []byte, key ...string)

Put is the badger implementation of Database.Put

func (*BadgerDatabase) Rollback added in v0.2.0 

func (db *BadgerDatabase) Rollback()

Rollback is the badger implementation of Database.Rollback

type Batch 

type Batch interface {
	// Put sets `val` at `key`.
	Put(val []byte, key ...string)

	// Clear all contents below and including `key`.
	Clear(key ...string) error

	// Erase a key from the database.
	Erase(key ...string)

	// Flush the batch to the database.
	// Only now, all changes will be written to disk.
	Flush() error

	// Rollback will forget all changes without executing them.
	Rollback()

	// HaveWrites returns true when the batch contains something
	// we can write to the disk on Flush().
	HaveWrites() bool
}

Batch is an API object used to model a transaction.

type Database 

type Database interface {
	// Get retrievies the key `key` out of bucket.
	// If no such key exists, it will return (nil, ErrNoSuchKey)
	// If a badge is currently open, Get() shall still return the
	// most current value currently set by the last Put() call
	// to `key`.
	Get(key ...string) ([]byte, error)

	// Keys iterates over all keys in the database If the error is returned by
	// `fn` the iteration stops and the error value is returned.
	// The keys are returned in lexical ordering.
	Keys(fn func(key []string) error, prefix ...string) error

	// Batch returns a new Batch object, that will allow modifications
	// of the state. Batch() can be called recursive: The changes will
	// only be flushed to disk if batch.Flush() was called equal times
	// to the number Batch() was called.
	Batch() Batch

	// Export backups all database content to `w` in
	// an implemenation specific format that can be read by Import.
	Export(w io.Writer) error

	// Import reads a previously exported db dump by Export from `r`.
	// Existing keys might be overwritten if the dump also contains them.
	Import(r io.Reader) error

	// Close closes the database. Since I/O may happen, an error is returned.
	Close() error

	// Glob finds all existing keys in the store, starting with prefix.
	Glob(prefix []string) ([][]string, error)
}

Database is a key/value store that offers different buckets for storage. Keys are strings, values are arbitrary untyped data.

type DiskDatabase 

type DiskDatabase struct {
	// contains filtered or unexported fields
}

DiskDatabase is a database that simply uses the filesystem as storage. Each bucket is one directory. Leaf keys are simple files. The exported form of the database is simply a gzipped .tar of the directory.

Note that this database backends was written for easy debugging. It is currently by no means optimized for fast reads and writes and could be probably made a lot faster if we ever need that.

func NewDiskDatabase 

func NewDiskDatabase(basePath string) (*DiskDatabase, error)

NewDiskDatabase creates a new database at `basePath`.

func (*DiskDatabase) Batch 

func (db *DiskDatabase) Batch() Batch

Batch is the disk implementation of Database.Batch

func (*DiskDatabase) Clear 

func (db *DiskDatabase) Clear(key ...string) error

Clear removes all keys below and including `key`.

func (*DiskDatabase) Close 

func (db *DiskDatabase) Close() error

Close the database

func (*DiskDatabase) Erase 

func (db *DiskDatabase) Erase(key ...string)

Erase is the disk implementation of Database.Erase

func (*DiskDatabase) Export 

func (db *DiskDatabase) Export(w io.Writer) error

Export writes all key/values into a gzipped .tar that is written to `w`.

func (*DiskDatabase) Flush 

func (db *DiskDatabase) Flush() error

Flush is the disk implementation of Database.Flush

func (*DiskDatabase) Get 

func (db *DiskDatabase) Get(key ...string) ([]byte, error)

Get a single value from `bucket` by `key`.

func (*DiskDatabase) Glob 

func (db *DiskDatabase) Glob(prefix []string) ([][]string, error)

Glob is the disk implementation of Database.Glob

func (*DiskDatabase) HaveWrites 

func (db *DiskDatabase) HaveWrites() bool

HaveWrites is the disk implementation of Database.HaveWrites

func (*DiskDatabase) Import 

func (db *DiskDatabase) Import(r io.Reader) error

Import a gzipped tar from `r` into the current database.

func (*DiskDatabase) Keys 

func (db *DiskDatabase) Keys(fn func(key []string) error, prefix ...string) error

Keys is the disk implementation of Database.Keys

func (*DiskDatabase) Put 

func (db *DiskDatabase) Put(val []byte, key ...string)

Put stores a new `val` under `key` at `bucket`. Implementation detail: `key` may contain slashes (/). If used, those keys will result in a nested directory structure.

func (*DiskDatabase) Rollback 

func (db *DiskDatabase) Rollback()

Rollback is the disk implementation of Database.Rollback

type MemoryDatabase 

type MemoryDatabase struct {
	// contains filtered or unexported fields
}

MemoryDatabase is a purely in memory database.

func NewMemoryDatabase 

func NewMemoryDatabase() *MemoryDatabase

NewMemoryDatabase allocates a new empty MemoryDatabase

func (*MemoryDatabase) Batch 

func (mdb *MemoryDatabase) Batch() Batch

Batch is a no-op for a memory database.

func (*MemoryDatabase) Clear 

func (mdb *MemoryDatabase) Clear(key ...string) error

Clear removes all keys includin and below `key`.

func (*MemoryDatabase) Close 

func (mdb *MemoryDatabase) Close() error

Close the memory - a no op.

func (*MemoryDatabase) Erase 

func (mdb *MemoryDatabase) Erase(key ...string)

Erase removes `key`

func (*MemoryDatabase) Export 

func (mdb *MemoryDatabase) Export(w io.Writer) error

Export encodes the internal memory map to a gob structure, and writes it to `w`.

func (*MemoryDatabase) Flush 

func (mdb *MemoryDatabase) Flush() error

Flush is a no-op for a memory database.

func (*MemoryDatabase) Get 

func (mdb *MemoryDatabase) Get(key ...string) ([]byte, error)

Get returns `key` of `bucket`.

func (*MemoryDatabase) Glob 

func (mdb *MemoryDatabase) Glob(prefix []string) ([][]string, error)

Glob returns all keys starting with `prefix`.

func (*MemoryDatabase) HaveWrites 

func (mdb *MemoryDatabase) HaveWrites() bool

HaveWrites returns true if there are any open writes.

func (*MemoryDatabase) Import 

func (mdb *MemoryDatabase) Import(r io.Reader) error

Import imports a previously exported dump and decodes the gob structure.

func (*MemoryDatabase) Keys 

func (mdb *MemoryDatabase) Keys(fn func(key []string) error, prefix ...string) error

Keys will return all keys currently stored in the memory map

func (*MemoryDatabase) Put 

func (mdb *MemoryDatabase) Put(data []byte, key ...string)

Put sets `key` in `bucket` to `data`.

func (*MemoryDatabase) Rollback 

func (mdb *MemoryDatabase) Rollback()

Rollback is a no-op for a memory database

Source Files

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