Class: Moneta::Adapters::ActiveRecord

Inherits:
Moneta::Adapter show all
Defined in:
lib/moneta/adapters/activerecord.rb,
lib/moneta/adapters/activerecord/backend.rb,
lib/moneta/adapters/activerecord/v5_backend.rb

Overview

ActiveRecord as key/value stores

Defined Under Namespace

Classes: Backend, V5Backend

Class Attribute Summary collapse

Instance Attribute Summary collapse

Attributes inherited from Moneta::Adapter

#backend

Instance Method Summary collapse

Methods inherited from Moneta::Adapter

backend, backend_block, backend_required?

Methods included from Config

#config, included

Methods included from Defaults

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

Methods included from OptionSupport

#expires, #prefix, #raw, #with

Constructor Details

#initialize(options = {}) ⇒ ActiveRecord

Returns a new instance of ActiveRecord.

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :backend (Object) —

    A class object inheriting from ActiveRecord::Base to use as a table

  • :table (String, Symbol) — default: :moneta —

    Table name

  • :connection (Hash/String/Symbol) —

    ActiveRecord connection configuration (‘Hash` or `String`), or symbol giving the name of a Rails connection (e.g. :production)

  • :create_table (Proc, Boolean) —

    Proc called with a connection if table needs to be created. Pass false to skip the create table check all together.

  • :key_column (Symbol) — default: :k —

    The name of the column to use for keys

  • :value_column (Symbol) — default: :v —

    The name of the column to use for values



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# File 'lib/moneta/adapters/activerecord.rb', line 58

def initialize(options = {})
  super
  @table = ::Arel::Table.new(backend.table_name)
end

Class Attribute Details

.table_create_lock ⇒ Object (readonly) 



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# File 'lib/moneta/adapters/activerecord.rb', line 14

def table_create_lock
  @table_create_lock
end

Instance Attribute Details

#table ⇒ Object (readonly) 



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# File 'lib/moneta/adapters/activerecord.rb', line 19

def table
  @table
end

Instance Method Details

#clear(options = {}) ⇒ void

This method returns an undefined value.

Clear all keys in this store

Parameters:

  • options (Hash) (defaults to: {}) 


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# File 'lib/moneta/adapters/activerecord.rb', line 146

def clear(options = {})
  with_connection do |conn|
    conn.delete(arel_del)
  end
  self
end

#close ⇒ Object

Explicitly close the store

Returns:

  • nil



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# File 'lib/moneta/adapters/activerecord.rb', line 154

def close
  @table = nil
  @connection_pool = 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



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# File 'lib/moneta/adapters/activerecord.rb', line 136

def create(key, value, options = {})
  with_connection do |conn|
    conn_ins(conn, key, value)
    true
  end
rescue ::ActiveRecord::RecordNotUnique
  false
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



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# File 'lib/moneta/adapters/activerecord.rb', line 98

def delete(key, options = {})
  with_connection do |conn|
    conn.transaction do
      sel = arel_sel_key(key).project(table[config.value_column]).lock
      value = decode(conn, conn.select_value(sel))

      del = arel_del.where(table[config.key_column].eq(key))
      conn.delete(del)

      value
    end
  end
end

#each_key ⇒ Enumerator #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_key ⇒ Enumerator

    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) 


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# File 'lib/moneta/adapters/activerecord.rb', line 73

def each_key(&block)
  with_connection do |conn|
    return enum_for(:each_key) { conn.select_value(arel_sel.project(table[config.key_column].count)) } unless block_given?
    conn.select_values(arel_sel.project(table[config.key_column])).each { |k| yield(k) }
  end
  self
end

#fetch_values(*keys, **options) ⇒ Object #fetch_values(*keys, **options) {|key| ... } ⇒ Array<Object, nil>

Note:

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

Behaves identically to #values_at except that it accepts an optional block. When supplied, the block will be called successively with each supplied key that is not present in the store. The return value of the block call will be used in place of nil in returned the array of values.

Overloads:

  • #fetch_values(*keys, **options) {|key| ... } ⇒ Array<Object, nil>

    Returns Array containing the values requested, or where keys are missing, the return values from the corresponding block calls.

    Yield Parameters:

    • key (Object) —

      Each key that is not found in the store

    Yield Returns:

    • (Object, nil) —

      The value to substitute for the missing one

    Returns:

    • (Array<Object, nil>) —

      Array containing the values requested, or where keys are missing, the return values from the corresponding block calls



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# File 'lib/moneta/adapters/activerecord.rb', line 199

def fetch_values(*keys, **options)
  return values_at(*keys, **options) unless block_given?
  hash = Hash[slice(*keys, **options)]
  keys.map do |key|
    if hash.key?(key)
      hash[key]
    else
      yield key
    end
  end
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



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# File 'lib/moneta/adapters/activerecord.rb', line 113

def increment(key, amount = 1, options = {})
  with_connection do |conn|
    conn_ins(conn, key, amount.to_s)
    amount
  rescue ::ActiveRecord::RecordNotUnique
    conn.transaction do
      sel = arel_sel_key(key).project(table[config.value_column]).lock
      value = decode(conn, conn.select_value(sel))
      value = (value ? Integer(value) : 0) + amount
      # Re-raise if the upate affects no rows (i.e. row deleted after attempted insert,
      # before select for update)
      raise unless conn_upd(conn, key, value.to_s) == 1
      value
    end
  end
rescue ::ActiveRecord::RecordNotUnique, ::ActiveRecord::Deadlocked
  # This handles the "no row updated" issue, above, as well as deadlocks
  # which may occur on some adapters
  tries ||= 0
  (tries += 1) <= 3 ? retry : raise
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) 


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# File 'lib/moneta/adapters/activerecord.rb', line 64

def key?(key, options = {})
  with_connection do |conn|
    sel = arel_sel_key(key).project(::Arel.sql('1'))
    result = conn.select_all(sel)
    !result.empty?
  end
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



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# File 'lib/moneta/adapters/activerecord.rb', line 82

def load(key, options = {})
  with_connection do |conn|
    conn_sel_value(conn, key)
  end
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) 


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# File 'lib/moneta/adapters/activerecord.rb', line 212

def merge!(pairs, options = {})
  with_connection do |conn|
    conn.transaction do
      existing = Hash[slice(*pairs.map { |k, _| k }, lock: true, **options)]
      update_pairs, insert_pairs = pairs.partition { |k, _| existing.key?(k) }
      insert_pairs.each { |key, value| conn_ins(conn, key, encode(conn, value)) }

      if block_given?
        update_pairs.map! do |key, new_value|
          [key, yield(key, existing[key], new_value)]
        end
      end

      update_pairs.each { |key, value| conn_upd(conn, key, encode(conn, value)) }
    end
  end

  self
end

#slice(*keys, lock: false, **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



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# File 'lib/moneta/adapters/activerecord.rb', line 160

def slice(*keys, lock: false, **options)
  with_connection do |conn|
    conn.create_table(:slice_keys, temporary: true) do |t|
      t.string :key, null: false
    end

    begin
      temp_table = ::Arel::Table.new(:slice_keys)
      keys.each do |key|
        conn.insert ::Arel::InsertManager.new
          .into(temp_table)
          .insert([[temp_table[:key], key]])
      end

      sel = arel_sel
        .join(temp_table)
        .on(table[config.key_column].eq(temp_table[:key]))
        .project(table[config.key_column], table[config.value_column])
      sel = sel.lock if lock
      result = conn.select_all(sel)

      k = config.key_column.to_s
      v = config.value_column.to_s
      result.map do |row|
        [row[k], decode(conn, row[v])]
      end
    ensure
      conn.drop_table(:slice_keys)
    end
  end
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



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# File 'lib/moneta/adapters/activerecord.rb', line 89

def store(key, value, options = {})
  with_connection do |conn|
    encoded = encode(conn, value)
    conn_ins(conn, key, encoded) unless conn_upd(conn, key, encoded) == 1
  end
  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



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# File 'lib/moneta/adapters/activerecord.rb', line 193

def values_at(*keys, **options)
  hash = Hash[slice(*keys, **options)]
  keys.map { |key| hash[key] }
end