Class: Moneta::Adapters::LMDB

Inherits:
Object
  • Object
show all
Includes:
Defaults
Defined in:
lib/moneta/adapters/lmdb.rb

Overview

LMDB backend

Constant Summary collapse

PUT_FLAGS =
[:nooverwrite, :nodupdata, :current, :append, :appenddup]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Defaults

#[], #[]=, #decrement, #features, #fetch, #fetch_values, included, #supports?, #update

Methods included from OptionSupport

#expires, #prefix, #raw, #with

Constructor Details

#initialize(options) ⇒ LMDB

Returns a new instance of LMDB

Parameters:

  • options (Hash)

Options Hash (options):

  • :dir (String)

    Environment directory

  • :backend (::LMDB::Environment)

    Use existing backend instance

  • :db (String or nil)

    Database name



20
21
22
23
24
25
26
27
28
29
30
# File 'lib/moneta/adapters/lmdb.rb', line 20

def initialize(options)
  db = options.delete(:db)
  @backend = options.delete(:backend) ||
    begin
      raise ArgumentError, 'Option :dir is required' unless dir = options.delete(:dir)
      FileUtils.mkpath(dir)
      ::LMDB.new(dir, options)
    end

  @db = @backend.database(db, create: true)
end

Instance Attribute Details

#backendObject (readonly)



12
13
14
# File 'lib/moneta/adapters/lmdb.rb', line 12

def backend
  @backend
end

#dbObject (readonly)



12
13
14
# File 'lib/moneta/adapters/lmdb.rb', line 12

def db
  @db
end

Instance Method Details

#clear(options = {}) ⇒ void

This method returns an undefined value.

Clear all keys in this store

Parameters:

  • options (Hash) (defaults to: {})


59
60
61
62
# File 'lib/moneta/adapters/lmdb.rb', line 59

def clear(options = {})
  @db.clear
  self
end

#closeObject

Explicitly close the store

Returns:

  • nil



87
88
89
90
# File 'lib/moneta/adapters/lmdb.rb', line 87

def close
  @backend.close
  nil
end

#create(key, value, options = {}) ⇒ Boolean

Note:

Not every Moneta store implements this method, a NotImplementedError is raised if it is not supported.

Atomically sets a key to value if it's not set.

Parameters:

  • key (Object)
  • value (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

Returns:

  • (Boolean)

    key was set



75
76
77
78
79
80
81
82
83
84
# File 'lib/moneta/adapters/lmdb.rb', line 75

def create(key, value, options = {})
  @backend.transaction do
    if @db.get(key)
      false
    else
      @db.put(key, value, Utils.only(options, *PUT_FLAGS))
      true
    end
  end
end

#delete(key, options = {}) ⇒ Object

Delete the key from the store and return the current value

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Object)

    current value



49
50
51
52
53
54
55
56
# File 'lib/moneta/adapters/lmdb.rb', line 49

def delete(key, options = {})
  @backend.transaction do
    if value = @db.get(key)
      @db.delete(key)
      value
    end
  end
end

#each_keyEnumerator #each_key {|key| ... } ⇒ self

Note:

Not every Moneta store implements this method, a NotImplementedError is raised if it is not supported.

Calls block once for each key in store, passing the key as a parameter. If no block is given, an enumerator is returned instead.

Overloads:

  • #each_keyEnumerator

    Returns An all-the-keys enumerator

    Returns:

    • (Enumerator)

      An all-the-keys enumerator

  • #each_key {|key| ... } ⇒ self

    Yield Parameters:

    • key (Object)

      Each key is yielded to the supplied block

    Returns:

    • (self)


93
94
95
96
97
98
99
100
101
102
103
# File 'lib/moneta/adapters/lmdb.rb', line 93

def each_key
  return enum_for(:each_key) { @db.size } unless block_given?

  @db.cursor do |cursor|
    while record = cursor.next
      yield record[0]
    end
  end

  self
end

#increment(key, amount = 1, options = {}) ⇒ Object

Note:

Not every Moneta store implements this method, a NotImplementedError is raised if it is not supported.

Atomically increment integer value with key

This method also accepts negative amounts.

Parameters:

  • key (Object)
  • amount (Integer) (defaults to: 1)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :prefix (String)

    Prefix key (See Transformer)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Object)

    value from store



65
66
67
68
69
70
71
72
# File 'lib/moneta/adapters/lmdb.rb', line 65

def increment(key, amount = 1, options = {})
  @backend.transaction do
    value = @db.get(key)
    value = Utils.to_int(value) + amount
    @db.put(key, value.to_s, Utils.only(options, *PUT_FLAGS))
    value
  end
end

#key?(key, options = {}) ⇒ Boolean

Exists the value with key

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :prefix (String)

    Prefix key (See Transformer)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Boolean)


33
34
35
# File 'lib/moneta/adapters/lmdb.rb', line 33

def key?(key, options = {})
  !@db.get(key).nil?
end

#load(key, options = {}) ⇒ Object

Fetch value with key. Return nil if the key doesn't exist

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • :sync (Boolean)

    Synchronized load (Cache reloads from adapter, Daybreak syncs with file)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Object)

    value



38
39
40
# File 'lib/moneta/adapters/lmdb.rb', line 38

def load(key, options = {})
  @db.get(key)
end

#merge!(pairs, options = {}) ⇒ self #merge!(pairs, options = {}) {|key, old_value, new_value| ... } ⇒ self

Note:

Some adapters may implement this method atomically, or in two passes when a block is provided. The default implmentation uses #key?, #load and #store.

Stores the pairs in the key-value store, and returns itself. When a block is provided, it will be called before overwriting any existing values with the key, old value and supplied value, and the return value of the block will be used in place of the supplied value.

Overloads:

  • #merge!(pairs, options = {}) ⇒ self

    Parameters:

    • pairs (<(Object, Object)>)

      A collection of key-value pairs to store

    • options (Hash) (defaults to: {})

    Returns:

    • (self)
  • #merge!(pairs, options = {}) {|key, old_value, new_value| ... } ⇒ self

    Parameters:

    • pairs (<(Object, Object)>)

      A collection of key-value pairs to store

    • options (Hash) (defaults to: {})

    Yield Parameters:

    • key (Object)

      A key that whose value is being overwritten

    • old_value (Object)

      The existing value which is being overwritten

    • new_value (Object)

      The value supplied in the method call

    Yield Returns:

    • (Object)

      The value to use for overwriting

    Returns:

    • (self)


116
117
118
# File 'lib/moneta/adapters/lmdb.rb', line 116

def merge!(pairs, options = {})
  @backend.transaction { super }
end

#slice(*keys, **options) ⇒ <(Object, Object)>

Note:

The keys in the return value may be the same objects that were supplied (i.e. Object#equal?), or may simply be equal (i.e. Object#==).

Note:

Some adapters may implement this method atomically. The default implmentation uses #values_at.

Returns a collection of key-value pairs corresponding to those supplied keys which are present in the key-value store, and their associated values. Only those keys present in the store will have pairs in the return value. The return value can be any enumerable object that yields pairs, so it could be a hash, but needn't be.

Parameters:

  • keys (<Object>)

    The keys for the values to fetch

  • options (Hash)

Options Hash (**options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • :sync (Boolean)

    Synchronized load (Cache reloads from adapter, Daybreak syncs with file)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (<(Object, Object)>)

    A collection of key-value pairs



111
112
113
# File 'lib/moneta/adapters/lmdb.rb', line 111

def slice(*keys, **options)
  @backend.transaction { super }
end

#store(key, value, options = {}) ⇒ Object

Store value with key

Parameters:

  • key (Object)
  • value (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :expires (Integer)

    Set expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • value



43
44
45
46
# File 'lib/moneta/adapters/lmdb.rb', line 43

def store(key, value, options = {})
  @db.put(key, value, Utils.only(options, *PUT_FLAGS))
  value
end

#values_at(*keys, **options) ⇒ Array<Object, nil>

Note:

Some adapters may implement this method atomically, but the default implementation simply makes repeated calls to #load.

Returns an array containing the values associated with the given keys, in the same order as the supplied keys. If a key is not present in the key-value-store, nil is returned in its place.

Parameters:

  • keys (<Object>)

    The keys for the values to fetch

  • options (Hash)

Options Hash (**options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • :sync (Boolean)

    Synchronized load (Cache reloads from adapter, Daybreak syncs with file)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Array<Object, nil>)

    Array containing the values requested, with nil for missing values



106
107
108
# File 'lib/moneta/adapters/lmdb.rb', line 106

def values_at(*keys, **options)
  @backend.transaction { super }
end