Class: KT

Inherits:
Object
  • Object
show all
Defined in:
lib/kt.rb,
lib/kt/kv.rb,
lib/kt/errors.rb,
lib/kt/version.rb

Defined Under Namespace

Classes: CASFailed, Error, KV, RecordNotFound

Constant Summary collapse

IDENTITY_ENCODING = 
"text/tab-separated-values"
BASE64_ENCODING = 
"text/tab-separated-values; colenc=B"
IDENTITY_HEADERS = 
{"Content-Type" => IDENTITY_ENCODING}
BASE64_HEADERS = 
{"Content-Type" => BASE64_ENCODING}
EMPTY_HEADERS = 
{}
VERSION = 
"0.3.0"

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ KT

Returns a new instance of KT.



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# File 'lib/kt.rb', line 16

def initialize(options)
  @host = options.fetch(:host, "127.0.0.1")
  @port = options.fetch(:port, 1978)
  @poolsize = options.fetch(:poolsize, 5)
  @timeout = options.fetch(:timeout, 5.0)

  @pool = ConnectionPool.new(size: @poolsize, timeout: @timeout) do
    Excon.new("http://#{@host}:#{@port}")
  end
end

Instance Method Details

#cas(key, oval = nil, nval = nil) ⇒ Object

cas executes a compare and swap operation if both old and new provided it sets to new value if previous value is old value if no old value provided it will set to new value if key is not present in db if no new value provided it will remove the record if it exists it returns true if it succeded or false otherwise



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# File 'lib/kt.rb', line 277

def cas(key, oval = nil, nval = nil)
  req = [KT::KV.new("key", key)]
  if oval != nil
    req << KT::KV.new("oval", oval)
  end
  if nval != nil
    req << KT::KV.new("nval", nval)
  end

  status, body = do_rpc("/rpc/cas", req)

  if status == 450
    return false
  end

  if status != 200
    raise_error(body)
  end

  return true
end

#cas!(key, oval = nil, nval = nil) ⇒ Object

cas! works the same as cas but it raises error on failure



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# File 'lib/kt.rb', line 300

def cas!(key, oval = nil, nval = nil)
  if !cas(key, oval, nval)
    raise KT::CASFailed.new("Failed compare and swap for #{key}")
  end
end

#clear ⇒ Object

clear removes all records in the database



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# File 'lib/kt.rb', line 39

def clear
  status, m = do_rpc("/rpc/clear")

  if status != 200
    raise_error(m)
  end
end

#count ⇒ Object

count returns the number of records in the database



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# File 'lib/kt.rb', line 28

def count
  status, m = do_rpc("/rpc/status")

  if status != 200
    raise_error(m)
  end

  find_rec(m, "count").value.to_i
end

#fetch(key, &block) ⇒ Object

fetch retrives the keys from cache if key is found it returns the unmarshaled value if key is not found it runs the block sends the value and returns it



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# File 'lib/kt.rb', line 108

def fetch(key, &block)
  value = get(key)
  if value
    Marshal::load(value)
  else
    block.call.tap do |value|
      set(key, Marshal::dump(value))
    end
  end
end

#get(key) ⇒ Object

get retrieves the data stored at key. It returns nil if no such data is found



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# File 'lib/kt.rb', line 58

def get(key)
  status, body = do_rest("GET", key, nil)

  case status
  when 200
    body
  when 404
    nil
  end
end

#get!(key) ⇒ Object

get! retrieves the data stored at key. KT::RecordNotFound is raised if not such data is found



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# File 'lib/kt.rb', line 71

def get!(key)
  value = get(key)
  if value != nil
    value
  else
    raise KT::RecordNotFound.new("Key: #{key} not found")
  end
end

#get_bulk(keys) ⇒ Object

get_bulk retrieves the keys in the list It returns a hash of key => value. If a key was not found in the database, the value in return hash will be nil



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# File 'lib/kt.rb', line 83

def get_bulk(keys)
  req = keys.map do |key|
    KT::KV.new("_#{key}", "")
  end

  status, res_body = do_rpc("/rpc/get_bulk", req)

  if status != 200
    raise_error(res_body)
  end

  res = {}

  res_body.each do |kv|
    if kv.key.start_with?('_')
      res[kv.key[1, kv.key.size - 1]] = kv.value
    end
  end

  return res
end

#match_prefix(prefix, max_records = -1)) ⇒ Object

match_prefix performs the match_prefix operation against the server It returns a sorted list of keys. max_records defines the number of results to be returned if negative, it means unlimited



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# File 'lib/kt.rb', line 249

def match_prefix(prefix, max_records = -1)
  req = [
    KT::KV.new("prefix", prefix),
    KT::KV.new("max", max_records.to_s)
  ]

  status, body = do_rpc("/rpc/match_prefix", req)

  if status != 200
    raise_error(body)
  end

  res = []

  body.each do |kv|
    if kv.key.start_with?('_')
      res << kv.key[1, kv.key.size - 1]
    end
  end

  return res
end

#pttl(key) ⇒ Object

pttl returns the time to live for a key in milliseconds if key does not exist, it returns -2 if key exists but no ttl is set, it returns -1 if key exists and it has a ttl, it returns the number of milliseconds remaining



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# File 'lib/kt.rb', line 150

def pttl(key)
  req = [
    KT::KV.new("key", key),
  ]

  status, res_body = do_rpc("/rpc/check", req)

  case status
  when 200
    xt_pos = res_body.index{|kv| kv.key == "xt"}
    if xt_pos != nil
      expire_time = res_body[xt_pos].value.to_f
      [expire_time - Time.now.to_f, 0].max
    else
      -1
    end
  when 450
    -2
  else
    raise_error(res_body)
  end
end

#remove(key) ⇒ Object

remove deletes the data at key in the database.



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# File 'lib/kt.rb', line 207

def remove(key)
  status, body = do_rest("DELETE", key, nil)

  if status == 404
    return false
  end

  if status != 204
    raise KT::Error.new(body)
  end

  return true
end

#remove!(key) ⇒ Object

remove! deletes the data at key in the database it raises KT::RecordNotFound if key was not found



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# File 'lib/kt.rb', line 223

def remove!(key)
  unless remove(key)
    raise KT::RecordNotFound.new("key #{key} was not found")
  end
end

#remove_bulk(keys) ⇒ Object

remove_bulk deletes multiple keys. it returnes the number of keys deleted



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# File 'lib/kt.rb', line 231

def remove_bulk(keys)
  req = keys.map do |key|
    KV.new("_#{key}", "")
  end

  status, body = do_rpc("/rpc/remove_bulk", req)

  if status != 200
    raise_error(body)
  end

  find_rec(body, "num").value.to_i
end

#set(key, value, expire: nil) ⇒ Object

set stores the data at key



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# File 'lib/kt.rb', line 174

def set(key, value, expire: nil)
  req = [
    KT::KV.new("key", key),
    KT::KV.new("value", value),
  ]

  if expire
    req << KT::KV.new("xt", expire.to_s)
  end

  status, body = do_rpc("/rpc/set", req)

  if status != 200
    raise_error(body)
  end
end

#set_bulk(values) ⇒ Object

set_bulk sets multiple keys to multiple values



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# File 'lib/kt.rb', line 192

def set_bulk(values)
  req = values.map do |key, value|
    KT::KV.new("_#{key}", value)
  end

  status, body = do_rpc("/rpc/set_bulk", req)

  if status != 200
    raise_error(body)
  end

  find_rec(body, "num").value.to_i
end

#ttl(key) ⇒ Object

ttl returns the time to live for a key in seconds if key does not exist, it returns -2 if key exists but no ttl is set, it returns -1 if key exists and it has a ttl, it returns the number of seconds remaining



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# File 'lib/kt.rb', line 123

def ttl(key)
  req = [
    KT::KV.new("key", key),
  ]

  status, res_body = do_rpc("/rpc/check", req)

  case status
  when 200
    xt_pos = res_body.index{|kv| kv.key == "xt"}
    if xt_pos != nil
      expire_time = res_body[xt_pos].value.to_f
      [(expire_time - Time.now.to_f).to_i, 0].max
    else
      -1
    end
  when 450
    -2
  else
    raise_error(res_body)
  end
end

#vacuum ⇒ Object

vacuum triggers garbage collection of expired records



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# File 'lib/kt.rb', line 48

def vacuum
  status, m = do_rpc("/rpc/vacuum")

  if status != 200
    raise_error(m)
  end
end