Class: Mongo::Collection::View::MapReduce

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Enumerable, Immutable, Loggable, Retryable
Defined in:
lib/mongo/collection/view/map_reduce.rb

Overview

Provides behavior around a map/reduce operation on the collection view.

Since:

  • 2.0.0

Constant Summary collapse

INLINE =

The inline option.

Since:

  • 2.1.0

'inline'.freeze
REROUTE =
Deprecated.

Reroute message.

Since:

  • 2.1.0

'Rerouting the MapReduce operation to the primary server.'.freeze

Constants included from Loggable

Loggable::PREFIX

Instance Attribute Summary collapse

Attributes included from Immutable

#options

Instance Method Summary collapse

Methods included from Retryable

#read_worker, #select_server, #write_worker

Methods included from Loggable

#log_debug, #log_error, #log_fatal, #log_info, #log_warn, #logger

Constructor Details

#initialize(view, map, reduce, options = {}) ⇒ MapReduce

Initialize the map/reduce for the provided collection view, functions and options.

Examples:

Create the new map/reduce view.

Parameters:

  • view (Collection::View) —

    The collection view.

  • map (String) —

    The map function.

  • reduce (String) —

    The reduce function.

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

    The map/reduce options.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 121

def initialize(view, map, reduce, options = {})
  @view = view
  @map_function = map.dup.freeze
  @reduce_function = reduce.dup.freeze
  @options = BSON::Document.new(options).freeze

  client.log_warn('The map_reduce operation is deprecated, please use the aggregation pipeline instead')
end

Instance Attribute Details

#map_function ⇒ String (readonly)

Returns map The map function.

Returns:

  • (String) —

    map The map function.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 48

def map_function
  @map_function
end

#reduce_function ⇒ String (readonly)

Returns reduce The reduce function.

Returns:

  • (String) —

    reduce The reduce function.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 51

def reduce_function
  @reduce_function
end

#view ⇒ View (readonly)

Returns view The collection view.

Returns:

  • (View) —

    view The collection view.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 45

def view
  @view
end

Instance Method Details

#each {|Each| ... } ⇒ Enumerator

Iterate through documents returned by the map/reduce.

Examples:

Iterate through the result of the map/reduce.

map_reduce.each do |document|
  p document
end

Yield Parameters:

  • Each (Hash) —

    matching document.

Returns:

  • (Enumerator) —

    The enumerator.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 71

def each
  @cursor = nil
  session = client.get_session(@options)
  server = cluster.next_primary(nil, session)
  context = Operation::Context.new(client: client, session: session, operation_timeouts: view.operation_timeouts)
  if server.load_balancer?
    # Connection will be checked in when cursor is drained.
    connection = server.pool.check_out(context: context)
    result = send_initial_query_with_connection(connection, context.session, context: context)
    result = send_fetch_query_with_connection(connection, session) unless inline?
  else
    result = send_initial_query(server, context)
    result = send_fetch_query(server, session) unless inline?
  end
  @cursor = Cursor.new(view, result, server, session: session)
  if block_given?
    @cursor.each do |doc|
      yield doc
    end
  else
    @cursor.to_enum
  end
end

#execute ⇒ Mongo::Operation::Result

Execute the map reduce, without doing a fetch query to retrieve the results

if outputted to a collection.

Examples:

Execute the map reduce and get the raw result.

map_reduce.execute

Returns:

Since:

  • 2.5.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 231

def execute
  view.send(:with_session, @options) do |session|
    write_concern = view.write_concern_with_session(session)
    context = Operation::Context.new(client: client, session: session)
    nro_write_with_retry(write_concern, context: context) do |connection, txn_num, context|
      send_initial_query_with_connection(connection, session, context: context)
    end
  end
end

#finalize(function = nil) ⇒ MapReduce, String

Set or get the finalize function for the operation.

Examples:

Set the finalize function.

map_reduce.finalize(function)

Parameters:

  • function (String) (defaults to: nil) —

    The finalize js function.

Returns:

  • (MapReduce, String) —

    The new MapReduce operation or the value of the function.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 106

def finalize(function = nil)
  configure(:finalize, function)
end

#js_mode(value = nil) ⇒ MapReduce, ...

Set or get the jsMode flag for the operation.

Examples:

Set js mode for the operation.

map_reduce.js_mode(true)

Parameters:

  • value (true, false) (defaults to: nil) —

    The jsMode value.

Returns:

  • (MapReduce, true, false) —

    The new MapReduce operation or the value of the jsMode flag.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 141

def js_mode(value = nil)
  configure(:js_mode, value)
end

#out(location = nil) ⇒ MapReduce, Hash

Set or get the output location for the operation.

Examples:

Set the output to inline.

map_reduce.out(inline: 1)

Set the output collection to merge.

map_reduce.out(merge: 'users')

Set the output collection to replace.

map_reduce.out(replace: 'users')

Set the output collection to reduce.

map_reduce.out(reduce: 'users')

Parameters:

  • location (Hash) (defaults to: nil) —

    The output location details.

Returns:

  • (MapReduce, Hash) —

    The new MapReduce operation or the value of the output location.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 165

def out(location = nil)
  configure(:out, location)
end

#out_collection_name ⇒ Object

Returns the collection name where the map-reduce result is written to. If the result is returned inline, returns nil.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 171

def out_collection_name
  if options[:out].respond_to?(:keys)
    options[:out][OUT_ACTIONS.find do |action|
      options[:out][action]
    end]
  end || options[:out]
end

#out_database_name ⇒ Object

Returns the database name where the map-reduce result is written to. If the result is returned inline, returns nil.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 181

def out_database_name
  if options[:out]
    if options[:out].respond_to?(:keys) && (db = options[:out][:db])
      db
    else
      database.name
    end
  end
end

#scope(object = nil) ⇒ MapReduce, Hash

Set or get a scope on the operation.

Examples:

Set the scope value.

map_reduce.scope(value: 'test')

Parameters:

  • object (Hash) (defaults to: nil) —

    The scope object.

Returns:

  • (MapReduce, Hash) —

    The new MapReduce operation or the value of the scope.

Since:

  • 2.0.0



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# File 'lib/mongo/collection/view/map_reduce.rb', line 202

def scope(object = nil)
  configure(:scope, object)
end

#verbose(value = nil) ⇒ MapReduce, Hash

Whether to include the timing information in the result.

Examples:

Set the verbose value.

map_reduce.verbose(false)

Parameters:

  • value (true, false) (defaults to: nil) —

    Whether to include timing information in the result.

Returns:

  • (MapReduce, Hash) —

    The new MapReduce operation or the value of the verbose option.

Since:

  • 2.0.5



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# File 'lib/mongo/collection/view/map_reduce.rb', line 218

def verbose(value = nil)
  configure(:verbose, value)
end