Class: Memcached

Inherits:
Object
  • Object
show all
Defined in:
lib/memcached/memcached.rb,
lib/memcached.rb,
lib/memcached/rails.rb,
lib/memcached/version.rb,
lib/memcached/behaviors.rb,
lib/memcached/exceptions.rb,
lib/memcached/experimental.rb,
lib/memcached/marshal_codec.rb

Overview

The Memcached client class.

Direct Known Subclasses

Rails

Defined Under Namespace

Modules: Experimental, MarshalCodec Classes: Rails

Constant Summary collapse

VERSION = 
'1.8.5'
BEHAVIORS = 
load_constants("MEMCACHED_BEHAVIOR_")
BEHAVIOR_VALUES = 
{
  false => 0,
  true => 1
}
HASH_VALUES = 
{}
DISTRIBUTION_VALUES = 
{}
DIRECT_VALUE_BEHAVIORS = 
[:retry_timeout, :connect_timeout, :rcv_timeout, :socket_recv_size, :poll_timeout, :socket_send_size, :server_failure_limit, :snd_timeout, :poll_max_retries]
CONVERSION_FACTORS = 
{
  :rcv_timeout => 1_000_000,
  :snd_timeout => 1_000_000,
  :poll_timeout => 1_000,
  :connect_timeout => 1_000
}
FLAGS = 
0x0
EMPTY_ARRAY = 
[].freeze
DEFAULTS = 
{
  :hash => :fnv1_32,
  :no_block => false,
  :noreply => false,
  :distribution => :consistent_ketama,
  :ketama_weighted => true,
  :buffer_requests => false,
  :cache_lookups => true,
  :support_cas => false,
  :tcp_nodelay => false,
  :show_backtraces => false,
  :retry_timeout => 60,
  :timeout => 0.25,
  :rcv_timeout => nil,
  :snd_timeout => nil,
  :poll_max_retries => 1,
  :poll_timeout => nil,
  :connect_timeout => 0.25,
  :prefix_key => '',
  :prefix_delimiter => '',
  :hash_with_prefix_key => true,
  :default_ttl => 604800,
  :default_weight => 8,
  :sort_hosts => false,
  :auto_eject_hosts => true,
  :server_failure_limit => 2,
  :verify_key => true,
  :use_udp => false,
  :binary_protocol => false,
  :credentials => nil,
  :experimental_features => false,
  :codec => Memcached::MarshalCodec,
  :exception_retry_limit => 5,
  :exceptions_to_retry => [
      Memcached::ServerIsMarkedDead,
      Memcached::ATimeoutOccurred,
      Memcached::ConnectionBindFailure,
      Memcached::ConnectionFailure,
      Memcached::ConnectionSocketCreateFailure,
      Memcached::Failure,
      Memcached::MemoryAllocationFailure,
      Memcached::ReadFailure,
      Memcached::ServerEnd,
      Memcached::ServerError,
      Memcached::SystemError,
      Memcached::UnknownReadFailure,
      Memcached::WriteFailure,
      Memcached::SomeErrorsWereReported]
}
IGNORED =

:stopdoc:

0
Error =

Superclass for all Memcached runtime exceptions.

Subclasses correspond one-to-one with server response strings or libmemcached errors. For example, raising Memcached::NotFound means that the server returned "NOT_FOUND\r\n".

Subclasses

  • Memcached::ABadKeyWasProvidedOrCharactersOutOfRange

  • Memcached::AKeyLengthOfZeroWasProvided

  • Memcached::ATimeoutOccurred

  • Memcached::ActionNotSupported

  • Memcached::ActionQueued

  • Memcached::ClientError

  • Memcached::ConnectionBindFailure

  • Memcached::ConnectionDataDoesNotExist

  • Memcached::ConnectionDataExists

  • Memcached::ConnectionFailure

  • Memcached::ConnectionSocketCreateFailure

  • Memcached::CouldNotOpenUnixSocket

  • Memcached::EncounteredAnUnknownStatKey

  • Memcached::Failure

  • Memcached::FetchWasNotCompleted

  • Memcached::HostnameLookupFailure

  • Memcached::ItemValue

  • Memcached::MemoryAllocationFailure

  • Memcached::NoServersDefined

  • Memcached::NotFound

  • Memcached::NotStored

  • Memcached::PartialRead

  • Memcached::ProtocolError

  • Memcached::ReadFailure

  • Memcached::ServerDelete

  • Memcached::ServerEnd

  • Memcached::ServerError

  • Memcached::ServerIsMarkedDead

  • Memcached::ServerValue

  • Memcached::SomeErrorsWereReported

  • Memcached::StatValue

  • Memcached::SystemError

  • Memcached::TheHostTransportProtocolDoesNotMatchThatOfTheClient

  • Memcached::UnknownReadFailure

  • Memcached::WriteFailure

Class.new(RuntimeError)
ERRNO_HASH = 
Hash[*Errno.constants.grep(/^E/).map{ |c| [Errno.const_get(c)::Errno, Errno.const_get(c).new.message]
EXCEPTIONS = 
[]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(servers = nil, opts = {}) ⇒ Memcached

Create a new Memcached instance. Accepts string or array of server strings, as well an an optional configuration hash.

Memcached.new('localhost', ...) # A single server
Memcached.new(['web001:11212', 'web002:11212'], ...) # Two servers with custom ports
Memcached.new(['web001:11211:2', 'web002:11211:8'], ...) # Two servers with default ports and explicit weights

Weights only affect Ketama hashing. If you use Ketama hashing and don’t specify a weight, the client will poll each server’s stats and use its size as the weight.

Valid option parameters are:

:prefix_key

A string to prepend to every key, for namespacing. Max length is 127. Defaults to the empty string.

:prefix_delimiter

A character to append to the prefix key. Defaults to the empty string.

:codec

An object to use as the codec for encoded requests. Defaults to Memcached::MarshalCodec.

:hash

The name of a hash function to use. Possible values are: :crc, :default, :fnv1_32, :fnv1_64, :fnv1a_32, :fnv1a_64, :hsieh, :md5, :murmur, and :none. :fnv1_32 is fast and well known, and is the default. Use :md5 for compatibility with other ketama clients. :none is for use when there is a single server, and performs no actual hashing.

:distribution

Either :modula, :consistent_ketama, :consistent_wheel, or :ketama. Defaults to :ketama.

:server_failure_limit

How many consecutive failures to allow before marking a host as dead. Has no effect unless :retry_timeout is also set.

:retry_timeout

How long to wait until retrying a dead server. Has no effect unless :server_failure_limit is non-zero. Defaults to 30.

:auto_eject_hosts

Whether to temporarily eject dead hosts from the pool. Defaults to true. Note that in the event of an ejection, :auto_eject_hosts will remap the entire pool unless :distribution is set to :consistent.

:exception_retry_limit

How many times to retry before raising exceptions in :exceptions_to_retry. Defaults to 5.

:exceptions_to_retry

Which exceptions to retry. Defaults to ServerIsMarkedDead, ATimeoutOccurred, ConnectionBindFailure, ConnectionFailure, ConnectionSocketCreateFailure, Failure, MemoryAllocationFailure, ReadFailure, ServerError, SystemError, UnknownReadFailure, and WriteFailure.

:cache_lookups

Whether to cache hostname lookups for the life of the instance. Defaults to true.

:support_cas

Flag CAS support in the client. Accepts true or false. Defaults to false because it imposes a slight performance penalty. Note that your server must also support CAS or you will trigger ProtocolError exceptions.

:tcp_nodelay

Turns on the no-delay feature for connecting sockets. Accepts true or false. Performance may or may not change, depending on your system.

:no_block

Whether to use pipelining for writes. Defaults to false.

:buffer_requests

Whether to use an internal write buffer. Accepts true or false. Calling get or closing the connection will force the buffer to flush. Client behavior is undefined unless :no_block is enabled. Defaults to false.

:noreply

Ask server not to reply for storage commands. Client behavior is undefined unless :no_block and :buffer_requests are enabled. Defaults to false.

:show_backtraces

Whether NotFound and NotStored exceptions should include backtraces. Generating backtraces is slow, so this is off by default. Turn it on to ease debugging.

:connect_timeout

How long to wait for a connection to a server. Defaults to 2 seconds. Set to 0 if you want to wait forever.

:timeout

How long to wait for a response from the server. Defaults to 0.25 seconds. Set to 0 if you want to wait forever.

:default_ttl

The ttl to use on set if no ttl is specified, in seconds. Defaults to one week. Set to 0 if you want things to never expire.

:default_weight

The weight to use if :ketama_weighted is true, but no weight is specified for a server.

:hash_with_prefix_key

Whether to include the prefix when calculating which server a key falls on. Defaults to true.

:use_udp

Use the UDP protocol to reduce connection overhead. Defaults to false.

:binary_protocol

Use the binary protocol. Defaults to false. Please note that using the binary protocol is usually slower than the ASCII protocol.

:sort_hosts

Whether to force the server list to stay sorted. This defeats consistent hashing and is rarely useful.

:verify_key

Validate keys before accepting them. Never disable this.

:poll_max_retries

Maximum poll timeout retries before marking a flush failed on timeouts.

Please note that when :no_block => true, update methods do not raise on errors. For example, if you try to set an invalid key, it will appear to succeed. The actual setting of the key occurs after libmemcached has returned control to your program, so there is no way to backtrack and raise the exception.



109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
 
# File 'lib/memcached/memcached.rb', line 109

def initialize(servers = nil, opts = {})
  @struct = Lib.memcached_create(nil)

  # Merge option defaults and discard meaningless keys
  @options = DEFAULTS.merge(opts)
  @options.each do |key,_|
     unless DEFAULTS.keys.include? key
       raise ArgumentError, "#{key.inspect} is not a valid configuration parameter."
     end
  end

  # Marginally speed up settings access for hot paths
  @default_ttl = options[:default_ttl]
  @codec = options[:codec]
  @support_cas = options[:support_cas]

  if servers == nil || servers == []
    if ENV.key?("MEMCACHE_SERVERS")
      servers = ENV["MEMCACHE_SERVERS"].split(",").map do | s | s.strip end
    else
      servers = "127.0.0.1:11211"
    end
  end

  if !options[:credentials] and ENV["MEMCACHE_USERNAME"] and ENV["MEMCACHE_PASSWORD"]
    options[:credentials] = [ENV["MEMCACHE_USERNAME"], ENV["MEMCACHE_PASSWORD"]]
  end

  instance_eval { send(:extend, Experimental) } if options[:experimental_features]

  # SASL requires binary protocol
  options[:binary_protocol] = true if options[:credentials]

  # UDP requires noreply
  options[:noreply] = true if options[:use_udp]

  # Buffering requires non-blocking
  # FIXME This should all be wrapped up in a single :pipeline option.
  options[:no_block] = true if options[:buffer_requests]

  # Disallow weights without ketama
  options.delete(:ketama_weighted) if options[:distribution] != :consistent_ketama

  # Disallow :sort_hosts with consistent hashing
  if options[:sort_hosts] and options[:distribution] == :consistent
    raise ArgumentError, ":sort_hosts defeats :consistent hashing"
  end

  # Read timeouts
  options[:rcv_timeout] ||= options[:timeout]
  options[:poll_timeout] ||= options[:timeout]

  # Write timeouts
  options[:snd_timeout] ||= options[:timeout]

  # Set the prefix key
  set_prefix_key(options[:prefix_key])

  # Set the behaviors and credentials on the struct
  set_behaviors
  set_credentials

  # Freeze the hash
  options.freeze

  # Set the servers on the struct
  set_servers(servers)

  # Not found exceptions
  @show_backtraces = options[:show_backtraces] ? nil : EMPTY_ARRAY
end

Instance Attribute Details

#options ⇒ Object (readonly)

:startdoc:



62
63
64
 
# File 'lib/memcached/memcached.rb', line 62

def options
  @options
end

Class Method Details

.load_constants(prefix, hash = {}) ⇒ Object

:stopdoc:



6
7
8
9
10
11
 
# File 'lib/memcached/behaviors.rb', line 6

def self.load_constants(prefix, hash = {})
  Lib.constants.grep(/^#{prefix}/).each do |const_name|
    hash[const_name[prefix.length..-1].downcase.to_sym] = Lib.const_get(const_name)
  end
  hash
end

Instance Method Details

#add(key, value, ttl = @default_ttl, encode = true, flags = FLAGS) ⇒ Object

Add a key/value pair. Raises Memcached::NotStored if the key already exists on the server. The parameters are the same as set.



333
334
335
336
337
338
339
340
341
342
343
344
345
346
 
# File 'lib/memcached/memcached.rb', line 333

def add(key, value, ttl=@default_ttl, encode=true, flags=FLAGS)
  value, flags = @codec.encode(key, value, flags) if encode
  begin
    check_return_code(
      Lib.memcached_add(@struct, key, value, ttl, flags),
      key
    )
  rescue => e
    tries ||= 0
    raise unless should_retry(e, tries)
    tries += 1
    retry
  end
end

#append(key, value) ⇒ Object

Appends a string to a key’s value. Accepts a String key and a String value. Raises Memcached::NotFound if the key does not exist on the server.

Note that the key must be initialized to an unencoded string first, via set, add, or replace with encode set to false.



400
401
402
403
404
405
406
407
408
409
410
411
 
# File 'lib/memcached/memcached.rb', line 400

def append(key, value)
  # Requires memcached 1.2.4
  check_return_code(
    Lib.memcached_append(@struct, key, value.to_s, IGNORED, IGNORED),
    key
  )
rescue => e
  tries ||= 0
  raise unless should_retry(e, tries)
  tries += 1
  retry
end

#cas(keys, ttl = @default_ttl, decode = true) ⇒ Object Also known as: compare_and_swap

Reads a key’s value from the server and yields it to a block. Replaces the key’s value with the result of the block as long as the key hasn’t been updated in the meantime, otherwise raises Memcached::NotStored. Accepts a String key and a block.

Also accepts an optional ttl value.

CAS stands for “compare and swap”, and avoids the need for manual key mutexing. CAS support must be enabled in Memcached.new or a Memcached::ClientError will be raised. Note that CAS may be buggy in memcached itself. :retry_on_exceptions does not apply to this method



433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
 
# File 'lib/memcached/memcached.rb', line 433

def cas(keys, ttl=@default_ttl, decode=true)
  raise ClientError, "CAS not enabled for this Memcached instance" unless options[:support_cas]
  tries ||= 0

  if keys.is_a? Array
    # Multi CAS
    hash, flags_and_cas = multi_get(keys, decode)
    unless hash.empty?
      hash = yield hash
      # Only CAS entries that were updated from the original hash
      hash.delete_if {|k, _| !flags_and_cas.has_key?(k) }
      hash = multi_cas(hash, ttl, flags_and_cas, decode, tries)
    end
    hash
  else
    # Single CAS
    value, flags, cas = single_get(keys, decode)
    value = yield value
    single_cas(keys, value, ttl, flags, cas, decode)
  end
rescue => e
  raise unless should_retry(e, tries)
  tries += 1
  retry
end

#clone ⇒ Object Also known as: dup

Safely copy this instance. Returns a Memcached instance.

clone is useful for threading, since each thread must have its own unshared Memcached object.



245
246
247
248
249
250
 
# File 'lib/memcached/memcached.rb', line 245

def clone
  memcached = super
  struct = Lib.memcached_clone(nil, @struct)
  memcached.instance_variable_set('@struct', struct)
  memcached
end

#decrement(key, offset = 1) ⇒ Object Also known as: decr

Decrement a key’s value. The parameters and exception behavior are the same as increment.



365
366
367
368
369
370
371
372
373
374
 
# File 'lib/memcached/memcached.rb', line 365

def decrement(key, offset=1)
  ret, value = Lib.memcached_decrement(@struct, key, offset)
  check_return_code(ret, key)
  value
rescue => e
  tries ||= 0
  raise unless should_retry(e, tries)
  tries += 1
  retry
end

#delete(key) ⇒ Object

Deletes a key/value pair from the server. Accepts a String key. Raises Memcached::NotFound if the key does not exist.



464
465
466
467
468
469
470
471
472
473
474
 
# File 'lib/memcached/memcached.rb', line 464

def delete(key)
  check_return_code(
    Lib.memcached_delete(@struct, key, IGNORED),
    key
  )
rescue => e
  tries ||= 0
  raise unless should_retry(e, tries)
  tries += 1
  retry
end

#exist(key) ⇒ Object

Check if a key exists on the server. It will return nil if the value is found, or raise Memcached::NotFound if the key does not exist.



515
516
517
518
519
520
 
# File 'lib/memcached/memcached.rb', line 515

def exist(key)
  check_return_code(
    Lib.memcached_exist(@struct, key),
    key
  )
end

#flush ⇒ Object

Flushes all key/value pairs from all the servers.



477
478
479
480
481
482
483
484
485
486
 
# File 'lib/memcached/memcached.rb', line 477

def flush
  check_return_code(
    Lib.memcached_flush(@struct, IGNORED)
  )
rescue => e
  tries ||= 0
  raise unless should_retry(e, tries)
  tries += 1
  retry
end

#get(keys, decode = true) ⇒ Object

Gets a key’s value from the server. Accepts a String key or array of String keys.

Also accepts a decode value, which defaults to true. Set decode to false if you want the value to be returned directly as a String. Otherwise it will be assumed to be an encoded Ruby object and decoded.

If you pass a String key, and the key does not exist on the server, Memcached::NotFound will be raised. If you pass an array of keys, memcached’s multiget mode will be used, and a hash of key/value pairs will be returned. The hash will contain only the keys that were found.

The multiget behavior is subject to change in the future; however, for multiple lookups, it is much faster than normal mode.

Note that when you rescue Memcached::NotFound exceptions, you should use a the block rescue syntax instead of the inline syntax. Block rescues are very fast, but inline rescues are very slow.



500
501
502
503
504
505
506
507
508
509
510
511
 
# File 'lib/memcached/memcached.rb', line 500

def get(keys, decode=true)
  if keys.is_a? Array
    multi_get(keys, decode).first
  else
    single_get(keys, decode).first
  end
rescue => e
  tries ||= 0
  raise unless should_retry(e, tries)
  tries += 1
  retry
end

#get_from_last(key, decode = true) ⇒ Object

Gets a key’s value from the previous server. Only useful with random distribution.

Raises:

  • (ArgumentError) 


523
524
525
526
527
528
529
 
# File 'lib/memcached/memcached.rb', line 523

def get_from_last(key, decode=true)
  warn("Memcached#get_from_last is deprecated and was removed in newer versions of libmemcached")
  raise ArgumentError, "get_from_last() is not useful unless :random distribution is enabled." unless options[:distribution] == :random
  value, flags, ret = Lib.memcached_get_from_last_rvalue(@struct, key)
  check_return_code(ret, key)
  decode ? @codec.decode(key, value, flags) : value
end

#increment(key, offset = 1) ⇒ Object Also known as: incr

Increment a key’s value. Accepts a String key. Raises Memcached::NotFound if the key does not exist.

Also accepts an optional offset paramater, which defaults to 1. offset must be an integer.

Note that the key must be initialized to an unencoded integer first, via set, add, or replace with encode set to false.



353
354
355
356
357
358
359
360
361
362
 
# File 'lib/memcached/memcached.rb', line 353

def increment(key, offset=1)
  ret, value = Lib.memcached_increment(@struct, key, offset)
  check_return_code(ret, key)
  value
rescue => e
  tries ||= 0
  raise unless should_retry(e, tries)
  tries += 1
  retry
end

#prefix_key ⇒ Object

Return the current prefix key.



232
233
234
235
236
237
238
 
# File 'lib/memcached/memcached.rb', line 232

def prefix_key
  if @struct.prefix_key.size > 0
    @struct.prefix_key[0..-1 - options[:prefix_delimiter].size]
  else
    ""
  end
end

#prepend(key, value) ⇒ Object

Prepends a string to a key’s value. The parameters and exception behavior are the same as append.



414
415
416
417
418
419
420
421
422
423
424
425
 
# File 'lib/memcached/memcached.rb', line 414

def prepend(key, value)
  # Requires memcached 1.2.4
  check_return_code(
    Lib.memcached_prepend(@struct, key, value.to_s, IGNORED, IGNORED),
    key
  )
rescue => e
  tries ||= 0
  raise unless should_retry(e, tries)
  tries += 1
  retry
end

#quit ⇒ Object

Disconnect from all currently connected servers



269
270
271
272
 
# File 'lib/memcached/memcached.rb', line 269

def quit
  Lib.memcached_quit(@struct)
  self
end

#replace(key, value, ttl = @default_ttl, encode = true, flags = FLAGS) ⇒ Object

Replace a key/value pair. Raises Memcached::NotFound if the key does not exist on the server. The parameters are the same as set.



382
383
384
385
386
387
388
389
390
391
392
393
394
395
 
# File 'lib/memcached/memcached.rb', line 382

def replace(key, value, ttl=@default_ttl, encode=true, flags=FLAGS)
  value, flags = @codec.encode(key, value, flags) if encode
  begin
    check_return_code(
      Lib.memcached_replace(@struct, key, value, ttl, flags),
      key
    )
  rescue => e
    tries ||= 0
    raise unless should_retry(e, tries)
    tries += 1
    retry
  end
end

#reset(current_servers = nil) ⇒ Object

Reset the state of the libmemcached struct. This is useful for changing the server list at runtime.



253
254
255
256
257
258
259
260
261
262
263
264
265
266
 
# File 'lib/memcached/memcached.rb', line 253

def reset(current_servers = nil)
  # Store state and teardown
  current_servers ||= servers
  prev_prefix_key = prefix_key
  quit

  # Create
  # FIXME Duplicates logic with initialize()
  @struct = Lib.memcached_create(nil)
  set_prefix_key(prev_prefix_key)
  set_behaviors
  set_credentials
  set_servers(current_servers)
end

#server_by_key(key) ⇒ Object

Return the server used by a particular key.



534
535
536
537
538
539
540
541
542
543
 
# File 'lib/memcached/memcached.rb', line 534

def server_by_key(key)
  ret = Lib.memcached_server_by_key(@struct, key)
  if ret.is_a?(Array)
    check_return_code(ret.last)
    inspect_server(ret.first)
  else
    check_return_code(ret)
  end
rescue ABadKeyWasProvidedOrCharactersOutOfRange
end

#servers ⇒ Object

Return the array of server strings used to configure this instance.



211
212
213
214
215
 
# File 'lib/memcached/memcached.rb', line 211

def servers
  server_structs.map do |server|
    inspect_server(server)
  end
end

#set(key, value, ttl = @default_ttl, encode = true, flags = FLAGS) ⇒ Object

Set a key/value pair. Accepts a String key and an arbitrary Ruby object. Overwrites any existing value on the server.

Accepts an optional ttl value to specify the maximum lifetime of the key on the server, in seconds. ttl must be a FixNum. 0 means no ttl. Note that there is no guarantee that the key will persist as long as the ttl, but it will not persist longer.

Also accepts an encode value, which defaults to true and uses the default Marshal codec. Set encode to false, and pass a String as the value, if you want to set a raw byte array.



317
318
319
320
321
322
323
324
325
326
327
328
329
330
 
# File 'lib/memcached/memcached.rb', line 317

def set(key, value, ttl=@default_ttl, encode=true, flags=FLAGS)
  value, flags = @codec.encode(key, value, flags) if encode
  begin
    check_return_code(
      Lib.memcached_set(@struct, key, value, ttl, flags),
      key
    )
  rescue => e
    tries ||= 0
    raise unless should_retry(e, tries)
    tries += 1
    retry
  end
end

#set_prefix_key(key) ⇒ Object

Set the prefix key.



218
219
220
221
222
223
224
225
226
227
228
229
 
# File 'lib/memcached/memcached.rb', line 218

def set_prefix_key(key)
  check_return_code(
    if key
      key += options[:prefix_delimiter]
      raise ArgumentError, "Max prefix key + prefix delimiter size is #{Lib::MEMCACHED_PREFIX_KEY_MAX_SIZE - 1}" unless
        key.size < Lib::MEMCACHED_PREFIX_KEY_MAX_SIZE
      Lib.memcached_callback_set(@struct, Lib::MEMCACHED_CALLBACK_PREFIX_KEY, key)
    else
      Lib.memcached_callback_set(@struct, Lib::MEMCACHED_CALLBACK_PREFIX_KEY, "")
    end
  )
end

#set_servers(servers) ⇒ Object

Set the server list. FIXME Does not necessarily free any existing server structs.



183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
 
# File 'lib/memcached/memcached.rb', line 183

def set_servers(servers)
  Array(servers).each_with_index do |server, index|
    # Socket
    check_return_code(
      if server.is_a?(String) and File.socket?(server)
        args = [@struct, server, options[:default_weight].to_i]
        Lib.memcached_server_add_unix_socket_with_weight(*args)
      # Network
      elsif server.is_a?(String) and server =~ /^[\w\.-]+(:\d{1,5}){0,2}$/
        host, port, weight = server.split(":")
        args = [@struct, host, port.to_i, (weight || options[:default_weight]).to_i]
        if options[:use_udp]
          Lib.memcached_server_add_udp_with_weight(*args)
        else
          Lib.memcached_server_add_with_weight(*args)
        end
      else
        raise ArgumentError, <<-MSG
Servers must be either in the format 'host:port[:weight]' (e.g., 'localhost:11211' or 'localhost:11211:10')
for a network server, or a valid path to a Unix domain socket (e.g., /var/run/memcached).
But it was #{server}.
        MSG
      end
    )
  end
end

#should_retry(exception, tries) ⇒ Object

Should retry the exception



275
276
277
278
279
280
281
282
283
284
 
# File 'lib/memcached/memcached.rb', line 275

def should_retry(exception, tries)
  return false unless options[:exception_retry_limit]
  return false unless tries < options[:exception_retry_limit]

  options[:exceptions_to_retry].each do |ex_class|
    return true if exception.instance_of?(ex_class)
  end

  false
end

#stats(subcommand = nil) ⇒ Object

Return a Hash of statistics responses from the set of servers. Each value is an array with one entry for each server, in the same order the servers were defined.



546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
 
# File 'lib/memcached/memcached.rb', line 546

def stats(subcommand = nil)
  stats = Hash.new([])

  stat_struct, ret = Lib.memcached_stat(@struct, subcommand)
  check_return_code(ret)

  keys, ret = Lib.memcached_stat_get_keys(@struct, stat_struct)
  check_return_code(ret)

  keys.each do |key|
     server_structs.size.times do |index|

       value, ret = Lib.memcached_stat_get_value(
         @struct,
         Lib.memcached_select_stat_at(@struct, stat_struct, index),
         key)
       check_return_code(ret, key)

       value = case value
         when /^\d+\.\d+$/ then value.to_f
         when /^\d+$/ then value.to_i
         else value
       end

       stats[key.to_sym] += [value]
     end
  end

  Lib.memcached_stat_free(@struct, stat_struct)
  stats
rescue Memcached::SomeErrorsWereReported => _
  e = _.class.new("Error getting stats")
  e.set_backtrace(_.backtrace)
  raise e
end