Class: Moneta::Adapters::Sequel

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

Overview

Sequel backend

Direct Known Subclasses

MySQL, Postgres, PostgresHStore, SQLite

Defined Under Namespace

Classes: IncrementError, MySQL, Postgres, PostgresHStore, SQLite

Constant Summary collapse

UniqueConstraintViolation =

Sequel::UniqueConstraintViolation is defined since sequel 3.44.0 older versions raise a Sequel::DatabaseError.

defined?(::Sequel::UniqueConstraintViolation) ? ::Sequel::UniqueConstraintViolation : ::Sequel::DatabaseError

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Defaults

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

Methods included from OptionSupport

#expires, #prefix, #raw, #with

Constructor Details

#initialize(options) ⇒ Sequel

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of Sequel


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

def initialize(options)
  @table_name = (options.delete(:table) || :moneta).to_sym
  @key_column = options.delete(:key_column) || :k
  @value_column = options.delete(:value_column) || :v
  @each_key_server = options.delete(:each_key_server)

  create_proc = options.delete(:create_table)
  if create_proc.nil?
    create_table
  elsif create_proc
    create_proc.call(@backend)
  end

  @table = @backend[@table_name]
  prepare_statements
end

Instance Attribute Details

#backendObject (readonly)


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# File 'lib/moneta/adapters/sequel.rb', line 15

def backend
  @backend
end

#key_columnObject (readonly)


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# File 'lib/moneta/adapters/sequel.rb', line 15

def key_column
  @key_column
end

#value_columnObject (readonly)


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# File 'lib/moneta/adapters/sequel.rb', line 15

def value_column
  @value_column
end

Class Method Details

.new(options = {}) ⇒ Object

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :db (String)

    Sequel database

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

    Table name

  • :extensions (Array) — default: []

    List of Sequel extensions

  • :connection_validation_timeout (Integer) — default: nil

    Sequel connection_validation_timeout

  • :backend (Sequel::Database)

    Use existing backend instance

  • :optimize (Boolean) — default: true

    Set to false to prevent database-specific optimisations

  • :create_table (Proc, Boolean)

    Provide a Proc for creating the table, or set to false to disable table creation all together. If a Proc is given, it will be called regardless of whether the table exists already.

  • :key_column (Symbol) — default: :k

    The name of the key column

  • :value_column (Symbol) — default: :v

    The name of the value column

  • :hstore (String)

    If using Postgres, keys and values are stored in a single row of the table in the value_column using the hstore format. The row to use is the one where the value_column is equal to the value of this option, and will be created if it doesn't exist.

  • :each_key_server (Symbol)

    Some adapters are unable to do multiple operations with a single connection. For these, it is possible to specify a separate connection to use for `#each_key`. Use in conjunction with Sequel's `:servers` option

  • All (Object)

    other options passed to `Sequel#connect`


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# File 'lib/moneta/adapters/sequel.rb', line 38

def self.new(options = {})
  extensions = options.delete(:extensions)
  connection_validation_timeout = options.delete(:connection_validation_timeout)
  optimize = options.delete(:optimize)
  backend = options.delete(:backend) ||
    begin
      raise ArgumentError, 'Option :db is required' unless db = options.delete(:db)
      other_cols = [:table, :create_table, :key_column, :value_column, :hstore]
      ::Sequel.connect(db, options.reject { |k,_| other_cols.member?(k) }).tap do |backend|
        if extensions
          raise ArgumentError, 'Option :extensions must be an Array' unless extensions.is_a?(Array)
          extensions.map(&:to_sym).each(&backend.method(:extension))
        end

        if connection_validation_timeout
          backend.pool.connection_validation_timeout = connection_validation_timeout
        end
      end
    end

  instance =
    if optimize.nil? || optimize
      case backend.database_type
      when :mysql
        MySQL.allocate
      when :postgres
        if options[:hstore]
          PostgresHStore.allocate
        elsif matches = backend.get(::Sequel[:version].function).match(/PostgreSQL (\d+)\.(\d+)/)
          # Our optimisations only work on Postgres 9.5+
          major, minor = matches[1..2].map(&:to_i)
          Postgres.allocate if major > 9 || (major == 9 && minor >= 5)
        end
      when :sqlite
        SQLite.allocate
      end
    end || allocate

  instance.instance_variable_set(:@backend, backend)
  instance.send(:initialize, options)
  instance
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/sequel.rb', line 161

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

#closeObject

Explicitly close the store

Returns:

  • nil


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# File 'lib/moneta/adapters/sequel.rb', line 167

def close
  @backend.disconnect
  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/sequel.rb', line 124

def create(key, value, options = {})
  @create.call(key: key, value: blob(value))
  true
rescue UniqueConstraintViolation
  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/sequel.rb', line 154

def delete(key, options = {})
  value = load(key, options)
  @delete.call(key: key)
  value
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)

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# File 'lib/moneta/adapters/sequel.rb', line 218

def each_key
  return enum_for(:each_key) { @table.count } unless block_given?
  if @each_key_server
    @table.server(@each_key_server).order(key_column).select(key_column).paged_each do |row|
      yield row[key_column]
    end
  else
    @table.select(key_column).order(key_column).paged_each(stream: false) do |row|
      yield row[key_column]
    end
  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/sequel.rb', line 184

def fetch_values(*keys, **options)
  return values_at(*keys, **options) unless block_given?
  existing = Hash[slice(*keys, **options)]
  keys.map do |key|
    if existing.key? key
      existing[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/sequel.rb', line 132

def increment(key, amount = 1, options = {})
  @backend.transaction do
    if existing = @load_for_update.call(key: key)
      existing_value = existing[value_column]
      amount += Integer(existing_value)
      raise IncrementError, "no update" unless @increment_update.call(
        key: key,
        value: existing_value,
        new_value: blob(amount.to_s)
      ) == 1
    else
      @create.call(key: key, value: blob(amount.to_s))
    end
    amount
  end
rescue ::Sequel::DatabaseError
  # Concurrent modification might throw a bunch of different errors
  tries ||= 0
  (tries += 1) < 10 ? 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/sequel.rb', line 100

def key?(key, options = {})
  @key.call(key: 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


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# File 'lib/moneta/adapters/sequel.rb', line 105

def load(key, options = {})
  if row = @load.call(key: key)
    row[value_column]
  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/sequel.rb', line 197

def merge!(pairs, options = {})
  @backend.transaction do
    existing = Hash[slice_for_update(pairs)]
    update_pairs, insert_pairs = pairs.partition { |k, _| existing.key?(k) }
    @table.import([key_column, value_column], blob_pairs(insert_pairs))

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

    update_pairs.each do |key, value|
      @store_update.call(key: key, value: blob(value))
    end
  end

  self
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


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# File 'lib/moneta/adapters/sequel.rb', line 173

def slice(*keys, **options)
  @slice.all(keys).map! { |row| [row[key_column], row[value_column]] }
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/sequel.rb', line 112

def store(key, value, options = {})
  blob_value = blob(value)
  unless @store_update.call(key: key, value: blob_value) == 1
    @create.call(key: key, value: blob_value)
  end
  value
rescue ::Sequel::DatabaseError
  tries ||= 0
  (tries += 1) < 10 ? retry : raise
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/sequel.rb', line 178

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