Class: Google::Cloud::Spanner::Database::List

Inherits:
Array
  • Object
show all
Defined in:
lib/google/cloud/spanner/database/list.rb

Overview

Database::List is a special case Array with additional values.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(arr = []) ⇒ List

Database instances.



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# File 'lib/google/cloud/spanner/database/list.rb', line 34

def initialize arr = []
  super arr
end

Instance Attribute Details

#token ⇒ Object

If not empty, indicates that there are more records that match the request and this value should be passed to continue.



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# File 'lib/google/cloud/spanner/database/list.rb', line 29

def token
  @token
end

Class Method Details

.from_grpc(grpc, service, instance_id, max = nil) ⇒ Object

Google::Spanner::Admin::Database::V1::ListDatabasesResponse object.



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# File 'lib/google/cloud/spanner/database/list.rb', line 147

def self.from_grpc grpc, service, instance_id, max = nil
  databases = List.new(Array(grpc.databases).map do |database|
    Database.from_grpc database, service
  end)
  databases.instance_variable_set :@instance_id, instance_id
  token = grpc.next_page_token
  token = nil if token == ""
  databases.instance_variable_set :@token,   token
  databases.instance_variable_set :@service, service
  databases.instance_variable_set :@max,     max
  databases
end

Instance Method Details

#all(request_limit: nil) {|database| ... } ⇒ Enumerator

Retrieves remaining results by repeatedly invoking #next until #next? returns ‘false`. Calls the given block once for each result, which is passed as the argument to the block.

An Enumerator is returned if no block is given.

This method will make repeated API calls until all remaining results are retrieved. (Unlike ‘#each`, for example, which merely iterates over the results returned by a single API call.) Use with caution.

Examples:

Iterating each database by passing a block:

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
databases.all do |database|
  puts database.database_id
end

Using the enumerator by not passing a block:

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
all_database_ids = databases.all.map do |database|
  database.database_id
end

Limit the number of API calls made:

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
databases.all(request_limit: 10) do |database|
  puts database.database_id
end

Parameters:

  • request_limit (Integer) (defaults to: nil) —

    The upper limit of API requests to make to load all databases. Default is no limit.

Yields:

  • (database) —

    The block for accessing each database.

Yield Parameters:

  • database (Database) —

    The database object.

Returns:

  • (Enumerator) 


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# File 'lib/google/cloud/spanner/database/list.rb', line 126

def all request_limit: nil
  request_limit = request_limit.to_i if request_limit
  unless block_given?
    return enum_for(:all, request_limit: request_limit)
  end
  results = self
  loop do
    results.each { |r| yield r }
    if request_limit
      request_limit -= 1
      break if request_limit < 0
    end
    break unless results.next?
    results = results.next
  end
end

#next ⇒ Database::List

Retrieve the next page of databases.

Examples:

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
if databases.next?
  next_databases = databases.next
end

Returns:



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# File 'lib/google/cloud/spanner/database/list.rb', line 70

def next
  return nil unless next?
  ensure_service!
  options = { token: token, max: @max }
  grpc = @service.list_databases @instance_id, options
  self.class.from_grpc grpc, @service, @max
end

#next? ⇒ Boolean

Whether there is a next page of databases.

Examples:

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
if databases.next?
  next_databases = databases.next
end

Returns:

  • (Boolean) 


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# File 'lib/google/cloud/spanner/database/list.rb', line 52

def next?
  !token.nil?
end