Class: Cequel::Metal::Keyspace

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Logging, MonitorMixin
Defined in:
lib/cequel/metal/keyspace.rb

Overview

Handle to a Cassandra keyspace (database). Keyspace objects are factories for DataSet instances and provide a handle to a Schema::Keyspace instance.

Since:

  • 1.0.0

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Logging

#slowlog=

Constructor Details

#initialize(configuration = {}) ⇒ Keyspace

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 Keyspace.

Parameters:

  • configuration (Options) (defaults to: {})

Options Hash (configuration):

  • :host (String) — default: '127.0.0.1' —

    hostname of single Cassandra instance to connect to

  • :port (Integer) — default: 9042 —

    port on which to connect to all specified hosts

  • :max_retries (Integer) —

    maximum number of retries on connection failure

  • :hosts (Array<String>) —

    list of Cassandra instances to connect to (hostnames only)

  • :username (String) —

    user to auth with (leave blank for no auth)

  • :password (String) —

    password to auth with (leave blank for no auth)

  • :keyspace (String) —

    name of keyspace to connect to

See Also:

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 92

def initialize(configuration={})
  configure(configuration)
  @lock = Monitor.new
end

Instance Attribute Details

#configuration ⇒ Hash (readonly)

Returns configuration options for this keyspace.

Returns:

  • (Hash) —

    configuration options for this keyspace

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 17

def configuration
  @configuration
end

#credentials ⇒ Hash (readonly)

Returns credentials for connect to cassandra.

Returns:

  • (Hash) —

    credentials for connect to cassandra

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 32

def credentials
  @credentials
end

#default_consistency ⇒ Symbol

Returns the default consistency for queries in this keyspace.

Returns:

  • (Symbol) —

    the default consistency for queries in this keyspace

Since:

  • 1.1.0



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# File 'lib/cequel/metal/keyspace.rb', line 225

def default_consistency
  @default_consistency || :quorum
end

#hosts ⇒ Array<String> (readonly)

Returns list of hosts to connect to.

Returns:

  • (Array<String>) —

    list of hosts to connect to

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 21

def hosts
  @hosts
end

#max_retries ⇒ Object (readonly)

Returns Integer maximum number of retries to reconnect to Cassandra.

Returns:

  • Integer maximum number of retries to reconnect to Cassandra

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 25

def max_retries
  @max_retries
end

#name ⇒ String (readonly)

Returns name of the keyspace.

Returns:

  • (String) —

    name of the keyspace

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 19

def name
  @name
end

#port ⇒ Object (readonly)

Returns Integer port to connect to Cassandra nodes on.

Returns:

  • Integer port to connect to Cassandra nodes on

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 23

def port
  @port
end

#retry_delay ⇒ Object (readonly)

Returns Float delay between retries to reconnect to Cassandra.

Returns:

  • Float delay between retries to reconnect to Cassandra

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 27

def retry_delay
  @retry_delay
end

Class Method Details

.sanitize(statement, bind_vars) ⇒ String

Combine a statement with bind vars into a fully-fledged CQL query. This will no longer be needed once the CQL driver supports bound values natively.

Parameters:

  • statement (String) —

    CQL statement with ? placeholders for bind vars

  • bind_vars (Array) —

    bind variables corresponding to ? in the statement

Returns:

  • (String) —

    CQL statement with quoted values in place of bind variables

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 75

def self.sanitize(statement, bind_vars)
  each_bind_var = bind_vars.each
  statement.gsub('?') { Type.quote(each_bind_var.next) }
end

Instance Method Details

#[](table_name) ⇒ DataSet

Returns data set encapsulating table.

Parameters:

  • table_name (Symbol) —

    the name of the table

Returns:

  • (DataSet) —

    data set encapsulating table

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 146

def [](table_name)
  DataSet.new(table_name.to_sym, self)
end

#batch { ... } ⇒ Object

Note:

If this method is created while already in a batch of the same type (logged or unlogged), this method is a no-op.

Execute write operations in a batch. Any inserts, updates, and deletes inside this method’s block will be executed inside a CQL BATCH operation.

Examples:

Perform inserts in a batch

DB.batch do
  DB[:posts].insert(:id => 1, :title => 'One')
  DB[:posts].insert(:id => 2, :title => 'Two')
end

Parameters:

  • options (Hash)

Yields:

  • context within which all write operations will be batched

Returns:

  • return value of block

Raises:

  • (ArgumentError) —

    if attempting to start a logged batch while already in an unlogged batch, or vice versa.



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# File 'lib/cequel/metal/keyspace.rb', line 61

def_delegator :batch_manager, :batch

#clear_active_connections! ⇒ void

This method returns an undefined value.

Clears all active connections

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 212

def clear_active_connections!
  if defined? @client
    remove_instance_variable(:@client)
  end
  if defined? @raw_client
    remove_instance_variable(:@raw_client)
  end
end

#client ⇒ Cql::Client::Client

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 the low-level client provided by the adapter.

Returns:

  • (Cql::Client::Client) —

    the low-level client provided by the adapter

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 155

def client
  synchronize do
    @client ||= raw_client.tap do |client|
      client.use(name) if name
    end
  end
end

#configure(configuration = {}) ⇒ void

This method returns an undefined value.

Configure this keyspace from a hash of options

Parameters:

  • configuration (Options) (defaults to: {}) —

    configuration options

Options Hash (configuration):

  • :host (String) — default: '127.0.0.1' —

    hostname of single Cassandra instance to connect to

  • :port (Integer) — default: 9042 —

    port on which to connect to all specified hosts

  • :max_retries (Integer) —

    maximum number of retries on connection failure

  • :hosts (Array<String>) —

    list of Cassandra instances to connect to (hostnames only)

  • :username (String) —

    user to auth with (leave blank for no auth)

  • :password (String) —

    password to auth with (leave blank for no auth)

  • :keyspace (String) —

    name of keyspace to connect to

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 116

def configure(configuration = {})
  if configuration.key?(:thrift)
    warn "Cequel no longer uses the Thrift transport to communicate " \
         "with Cassandra. The :thrift option is deprecated and ignored."
  end
  @configuration = configuration

  @hosts, @port = extract_hosts_and_port(configuration)
  @credentials  = extract_credentials(configuration)
  @max_retries  = extract_max_retries(configuration)
  @retry_delay  = extract_retry_delay(configuration)

  @name = configuration[:keyspace]
  @default_consistency = configuration[:default_consistency].try(:to_sym)

  # reset the connections
  clear_active_connections!
end

#execute(statement, *bind_vars) ⇒ Enumerable

Execute a CQL query in this keyspace

If a connection error occurs, will retry a maximum number of
time (default 3) before re-raising the original connection
error.

Parameters:

  • statement (String) —

    CQL string

  • bind_vars (Object) —

    values for bind variables

Returns:

  • (Enumerable) —

    the results of the query

See Also:

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 176

def execute(statement, *bind_vars)
  execute_with_consistency(statement, bind_vars, default_consistency)
end

#execute_with_consistency(statement, bind_vars, consistency) ⇒ Enumerable

Execute a CQL query in this keyspace with the given consistency

Parameters:

  • statement (String) —

    CQL string

  • bind_vars (Array) —

    array of values for bind variables

  • consistency (Symbol) —

    consistency at which to execute query

Returns:

  • (Enumerable) —

    the results of the query

Since:

  • 1.1.0



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# File 'lib/cequel/metal/keyspace.rb', line 190

def execute_with_consistency(statement, bind_vars, consistency)
  retries = max_retries

  log('CQL', statement, *bind_vars) do
    begin
      client.execute(sanitize(statement, bind_vars),
                     consistency || default_consistency)
    rescue Cql::NotConnectedError, Ione::Io::ConnectionError
      clear_active_connections!
      raise if retries == 0
      retries -= 1
      sleep(retry_delay)
      retry
    end
  end
end

#exists? ⇒ Boolean

Returns true if the keyspace exists.

Returns:

  • (Boolean) —

    true if the keyspace exists

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 230

def exists?
  statement = <<-CQL
    SELECT keyspace_name
    FROM system.schema_keyspaces
    WHERE keyspace_name = ?
  CQL

  log('CQL', statement, [name]) do
    raw_client.execute(sanitize(statement, [name])).any?
  end
end

#sanitize ⇒ String

Combine a statement with bind vars into a fully-fledged CQL query. This will no longer be needed once the CQL driver supports bound values natively.

Parameters:

  • statement (String) —

    CQL statement with ? placeholders for bind vars

  • bind_vars (Array) —

    bind variables corresponding to ? in the statement

Returns:

  • (String) —

    CQL statement with quoted values in place of bind variables



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# File 'lib/cequel/metal/keyspace.rb', line 84

def_delegator 'self.class', :sanitize

#schema ⇒ Schema::Keyspace

Returns schema object providing full read/write access to database schema.

Returns:

  • (Schema::Keyspace) —

    schema object providing full read/write access to database schema

Since:

  • 1.0.0



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# File 'lib/cequel/metal/keyspace.rb', line 138

def schema
  Schema::Keyspace.new(self)
end

#write(statement, *bind_vars) ⇒ void

This method returns an undefined value.

Write data to this keyspace using a CQL query. Will be included the current batch operation if one is present.



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# File 'lib/cequel/metal/keyspace.rb', line 43

def_delegator :write_target, :execute, :write

#write_with_consistency(statement, bind_vars, consistency) ⇒ void

This method returns an undefined value.

Write data to this keyspace using a CQL query at the given consistency. Will be included the current batch operation if one is present.



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# File 'lib/cequel/metal/keyspace.rb', line 54

def_delegator :write_target, :execute_with_consistency,
:write_with_consistency