Class: Aws::SessionStore::DynamoDB::Configuration

Inherits:
Object
  • Object
show all
Defined in:
lib/aws/session_store/dynamo_db/configuration.rb

Overview

This class provides a Configuration object for all DynamoDB session store operations by pulling configuration options from Runtime, a YAML file, the ENV, and default settings, in that order.

Environment Variables

The Configuration object can load default values from your environment. All configuration keys are supported except for ‘:dynamo_db_client` and `:error_handler`. The keys take the form of DYNAMO_DB_SESSION_<KEY_NAME>. Example:

export DYNAMO_DB_SESSION_TABLE_NAME='Sessions'
export DYNAMO_DB_SESSION_TABLE_KEY='id'

Locking Strategy

By default, locking is disabled for session store access. To enable locking, set the ‘:enable_locking` option to true. The locking strategy is pessimistic, meaning that only one read can be made on a session at once. While the session is being read by the process with the lock, other processes may try to obtain a lock on the same session but will be blocked. See the initializer for how to configure the pessimistic locking strategy to your needs.

Handling Errors

There are two configurable options for error handling: ‘:raise_errors` and `:error_handler`.

If you would like to use the Default Error Handler, you can decide to set ‘:raise_errors` to true or false depending on whether you want all errors, regardless of class, to be raised up the stack and essentially throw a 500.

If you decide to use your own Error Handler, you must implement the ‘BaseErrorHandler` class and pass it into the `:error_handler` option.

DynamoDB Specific Options

You may configure the table name and table hash key value of your session table with the ‘:table_name` and `:table_key` options. You may also configure performance options for your table with the `:consistent_read`, `:read_capacity`, `:write_capacity`. For more information about these configurations see {docs.aws.amazon.com/sdk-for-ruby/v3/api/Aws/DynamoDB/Client.html#create_table-instance_method CreateTable } method for Amazon DynamoDB.

See Also:

  • Interface for Error Handling for DynamoDB Session Store.

Constant Summary collapse

MEMBERS =

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

{
  table_name: 'sessions',
  table_key: 'session_id',
  secret_key: nil,
  consistent_read: true,
  read_capacity: 10,
  write_capacity: 5,
  raise_errors: false,
  error_handler: nil,
  max_age: nil,
  max_stale: nil,
  enable_locking: false,
  lock_expiry_time: 500,
  lock_retry_delay: 500,
  lock_max_wait_time: 1,
  config_file: nil,
  dynamo_db_client: nil
}.freeze

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Configuration

Provides configuration object that allows access to options defined during Runtime, in a YAML file, in the ENV, and by default.

Parameters:

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

    a customizable set of options

Options Hash (options):

  • :table_name (String) — default: "sessions" —

    Name of the session table.

  • :table_key (String) — default: "session_id" —

    The hash key of the session table.

  • :secret_key (String) —

    Secret key for HMAC encryption.

  • :consistent_read (Boolean) — default: true —

    If true, a strongly consistent read is used. If false, an eventually consistent read is used. @see docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.ReadConsistency.html

  • :read_capacity (Integer) — default: 10 —

    The maximum number of strongly consistent reads consumed per second before DynamoDB raises a ThrottlingException. @see docs.aws.amazon.com/amazondynamodb/latest/developerguide/read-write-operations.html

  • :write_capacity (Integer) — default: 5 —

    The maximum number of writes consumed per second before DynamoDB returns a ThrottlingException. @see docs.aws.amazon.com/amazondynamodb/latest/developerguide/read-write-operations.html

  • :raise_errors (Boolean) — default: false —

    If true, all errors are raised up the stack when default ErrorHandler. If false, Only specified errors are raised up the stack when the default ErrorHandler is used.

  • :error_handler (#handle_error) — default: Errors::DefaultHandler —

    An error handling object that handles all exceptions thrown during execution of the rack application.

  • :max_age (Integer) — default: nil —

    Maximum number of seconds earlier from the current time that a session was created.

  • :max_stale (Integer) — default: nil —

    Maximum number of seconds before current time that session was last accessed.

  • :enable_locking (Integer) — default: false —

    If true, a pessimistic locking strategy will be used for all session accesses.

  • :lock_expiry_time (Integer) — default: 500 —

    Time in milliseconds after which the lock expires on session.

  • :lock_retry_delay (Integer) — default: 500 —

    Time in milliseconds to wait before retrying to obtain lock once an attempt to obtain the lock has been made and has failed.

  • :lock_max_wait_time (Integer) — default: 500 —

    Maximum time in seconds to wait to acquire the lock before giving up.

  • :config_file (String, Pathname) —

    Path to a YAML file that contains configuration options.

  • :dynamo_db_client (Aws::DynamoDB::Client) — default: Aws::DynamoDB::Client.new —

    DynamoDB client used to perform database operations inside of the rack application.



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# File 'lib/aws/session_store/dynamo_db/configuration.rb', line 101

def initialize(options = {})
  opts = file_options(options).merge(options)
  opts = env_options.merge(opts)
  MEMBERS.each_pair do |opt_name, default_value|
    opts[opt_name] = default_value unless opts.key?(opt_name)
  end
  opts = opts.merge(dynamo_db_client: default_dynamo_db_client(opts))
  opts = opts.merge(error_handler: default_error_handler(opts)) unless opts[:error_handler]

  set_attributes(opts)
end

Instance Method Details

#to_hash ⇒ Hash

Returns The merged configuration hash.

Returns:

  • (Hash) —

    The merged configuration hash.



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# File 'lib/aws/session_store/dynamo_db/configuration.rb', line 118

def to_hash
  MEMBERS.each_with_object({}) do |(key, _), hash|
    hash[key] = send(key)
  end
end