github.com/Prakhar-Agarwal-byte/moby@v0.0.0-20231027092010-a14e3e8ab87e/libnetwork/internal/kvstore/kvstore.go (about)

     1  package kvstore
     2  
     3  import (
     4  	"errors"
     5  	"time"
     6  )
     7  
     8  // Backend represents a KV Store Backend
     9  type Backend string
    10  
    11  // BOLTDB backend
    12  const BOLTDB Backend = "boltdb"
    13  
    14  var (
    15  	// ErrBackendNotSupported is thrown when the backend k/v store is not supported by libkv
    16  	ErrBackendNotSupported = errors.New("Backend storage not supported yet, please choose one of")
    17  	// ErrKeyModified is thrown during an atomic operation if the index does not match the one in the store
    18  	ErrKeyModified = errors.New("Unable to complete atomic operation, key modified")
    19  	// ErrKeyNotFound is thrown when the key is not found in the store during a Get operation
    20  	ErrKeyNotFound = errors.New("Key not found in store")
    21  	// ErrPreviousNotSpecified is thrown when the previous value is not specified for an atomic operation
    22  	ErrPreviousNotSpecified = errors.New("Previous K/V pair should be provided for the Atomic operation")
    23  	// ErrKeyExists is thrown when the previous value exists in the case of an AtomicPut
    24  	ErrKeyExists = errors.New("Previous K/V pair exists, cannot complete Atomic operation")
    25  )
    26  
    27  // Config contains the options for a storage client
    28  type Config struct {
    29  	ConnectionTimeout time.Duration
    30  	Bucket            string
    31  	PersistConnection bool
    32  }
    33  
    34  // Store represents the backend K/V storage
    35  // Each store should support every call listed
    36  // here. Or it couldn't be implemented as a K/V
    37  // backend for libkv
    38  type Store interface {
    39  	// Put a value at the specified key
    40  	Put(key string, value []byte) error
    41  
    42  	// Get a value given its key
    43  	Get(key string) (*KVPair, error)
    44  
    45  	// Exists verifies if a Key exists in the store.
    46  	Exists(key string) (bool, error)
    47  
    48  	// List the content of a given prefix
    49  	List(directory string) ([]*KVPair, error)
    50  
    51  	// AtomicPut performs an atomic CAS operation on a single value.
    52  	// Pass previous = nil to create a new key.
    53  	AtomicPut(key string, value []byte, previous *KVPair) (*KVPair, error)
    54  
    55  	// AtomicDelete performs an atomic delete of a single value.
    56  	AtomicDelete(key string, previous *KVPair) error
    57  
    58  	// Close the store connection
    59  	Close()
    60  }
    61  
    62  // KVPair represents {Key, Value, Lastindex} tuple
    63  type KVPair struct {
    64  	Key       string
    65  	Value     []byte
    66  	LastIndex uint64
    67  }