Class: TimeSeries

Inherits:
RedisConnection show all
Defined in:
lib/time_series.rb

Overview

TimeSeries Class

Instance Attribute Summary collapse

Attributes inherited from RedisConnection

#redis

Instance Method Summary collapse

Constructor Details

#initialize(name, options = {}) ⇒ TimeSeries

Create Timeseries.

Options Hash (options):

  • :resolution (String) —

    The time resolution: :year, :month, :day, :hour, :minute, :second

  • :duration (Integer) —

    Duration is under development. It will allow for example 10, 20 or 30 seconds keys. Now only keys with :minute resolution are available.



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# File 'lib/time_series.rb', line 25

def initialize name, options={}
  super # initialize RedisConnection
  
  @name = name
  @prefix="#{$app_prefix}:ts:#{@name}:"
  
  # parse the resolution option
  if options.has_key? :resolution
    @resolution = options[:resolution]
    resolutions = [:year, :month, :day, :hour, :minute, :second]
    #if the resolution option is invalid raise an exception
    unless resolutions.include?(@resolution) #or @resolution.is_a?(Integer)
      raise ArgumentError.new("resolution can be either :year or :month or :day or :hour or :minute or :second")
    end  
  elsif keys.empty? # default resolution is :minute
        @resolution = :minute
  else # try to guess resolution from existing keys
    max_res = 0
    keys.each do |k|
      res = k.count(':')
      max_res = res if res > max_res
    end
    
    case max_res
      when 8 then @resolution = :second
      when 7 then @resolution = :minute
      when 6 then @resolution = :hour
      when 5 then @resolution = :day
      when 4 then @resolution = :month
      when 3 then @resolution = :year
      else raise ArgumentError.new("Cannot guess resolution from existing keys")
    end #case
  end # if
  
  # define the @duration based on @resolution
  case @resolution
    when :year   then @duration = 12*30*24*3600
    when :month  then @duration = 30*24*3600
    when :day    then @duration = 24*3600
    when :hour   then @duration = 3600
    when :minute then @duration = 60
    when :second then @duration = options[:duration] ||= 20
  end
end

Instance Attribute Details

#duration ⇒ Object (readonly)

Returns the value of attribute duration.



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

def duration
  @duration
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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

def name
  @name
end

#resolution ⇒ Object (readonly)

Returns the value of attribute resolution.



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

def resolution
  @resolution
end

Instance Method Details

#all ⇒ Hash

Returns the contents of all the keys TODO Considering to remove this method



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# File 'lib/time_series.rb', line 137

def all
  all = Hash.new
  keys.each{ |k| all[k.gsub(/#{@prefix}/,'')]=k.get}
  return all
end

#array_older_than(array, time) ⇒ Array

Removes recent keys from a key array



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# File 'lib/time_series.rb', line 190

def array_older_than array, time
  array.keep_if { |k| k.time <= Time.now - time }
end

#clear ⇒ Object

Deletes all the keys



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# File 'lib/time_series.rb', line 127

def clear
  i = 0
  keys.each{|k| @redis.del k; i+=1}
  return i 
end

#compress(keys) ⇒ Integer

Compress keys Key compression merges the given keys of the same resolution to keys of greater resolution. For example seconds are merged into minutes and days are merged into months. The values of the keys are merged too. After the merge the keys are deleted.



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# File 'lib/time_series.rb', line 289

def compress keys
  parents = []
  keys.each do |key|
    unless key.recent? or key.year?
      parent = key.parent
      parents << parent unless parents.include? parent
    end
  end
  
  i = 0
  parents.each do |parent|
    unless parent.recent?
      children = parent.persistant_children
      @redis.zunionstore parent, children
      children.each{|k| @redis.del k; i+=1}
    end
  end
  return i 
end

#current_key ⇒ String

Returns the current key



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# File 'lib/time_series.rb', line 99

def current_key
  time_to_key current_time, @resolution
end

#current_time ⇒ Time

Returns the current time.



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# File 'lib/time_series.rb', line 73

def current_time
  time=Time.at(Time.now.to_i) # this way nsec and usec is 0
  if @resolution == :second
    sec = time.strftime("%S").to_i % @duration
    time = time - sec
  end  
  return time
end

#day(time) ⇒ Object 



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# File 'lib/time_series.rb', line 333

def day time;    time_to_key(time, :day).get end

#days(*time) ⇒ Array

Keys with day resolution



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# File 'lib/time_series.rb', line 240

def days *time
  array = keys.keep_if { |k| k.day? and k.persistant?}
  if time.empty?
    return array
  else
    time = time.first
    return array_older_than array, time
  end    
end

#hour(time) ⇒ Object 



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# File 'lib/time_series.rb', line 334

def hour time;   time_to_key(time, :hour).get end

#hours(*time) ⇒ Array

Keys with hour resolution



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# File 'lib/time_series.rb', line 226

def hours *time
  array = keys.keep_if { |k| k.hour? and k.persistant?}
  if time.empty?
    return array
  else
    time = time.first
    return array_older_than array, time
  end    
end

#keys ⇒ Array

Returns all the keys



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# File 'lib/time_series.rb', line 120

def keys
  return @redis.keys"#{$app_prefix}:ts:#{@name}:*"
end

#last ⇒ Hash

Returns the contents of the last key



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# File 'lib/time_series.rb', line 146

def last
  last_key.get
end

#last_key ⇒ String

Returns the last key



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# File 'lib/time_series.rb', line 106

def last_key
  time_to_key last_time, @resolution
end

#last_time ⇒ Time

Returns the time of the last key.



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# File 'lib/time_series.rb', line 85

def last_time
  current_time - @duration
end

#minute(time) ⇒ Object 



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# File 'lib/time_series.rb', line 335

def minute time; time_to_key(time, :minute).get end

#minutes(*time) ⇒ Array

Keys with minute resolution



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# File 'lib/time_series.rb', line 212

def minutes *time
  array = keys.keep_if { |k| k.minute? and k.persistant?}
  if time.empty?
    return array
  else
    time = time.first
    return array_older_than array, time
  end    
end

#month(time) ⇒ Object 



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# File 'lib/time_series.rb', line 332

def month time;  time_to_key(time, :month).get end

#months(*time) ⇒ Array

Keys with month resolution



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# File 'lib/time_series.rb', line 254

def months *time
  array = keys.keep_if { |k| k.month? and k.persistant?}  
  if time.empty?
    return array
  else
    time = time.first
    return array_older_than array, time
  end  

end

#previous ⇒ Hash

Returns the contents of the previous key



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# File 'lib/time_series.rb', line 153

def previous
  previous_key.get
end

#previous_key ⇒ String

Returns the previous key



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# File 'lib/time_series.rb', line 113

def previous_key
 time_to_key previous_time, @resolution
end

#previous_time ⇒ Time

Returns the time of the previous key.



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# File 'lib/time_series.rb', line 92

def previous_time
  current_time - 2 * @duration
end

#push(term) ⇒ Object

Push a new Term into the Timeseries



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# File 'lib/time_series.rb', line 158

def push term
  @redis.zincrby current_key, 1, term
end

#remove_by_score(keys, *population) ⇒ Array

Remove terms with low scores



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# File 'lib/time_series.rb', line 313

def remove_by_score keys, *population
  if population.empty?
    population = 1
  else
    population = population.first
  end
  i = 0    
  keys.each {|k| @redis.zremrangebyscore(k, '-inf', population); i+=1} # TODO What zremrangebyscore returns?
  return i     
end

#second(time) ⇒ Object 



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# File 'lib/time_series.rb', line 336

def second time; time_to_key(time, :second).get end

#seconds(*time) ⇒ Array

Keys with second resolution



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# File 'lib/time_series.rb', line 198

def seconds *time
  array = keys.keep_if { |k| k.second? and k.persistant?}
  if time.empty?
    return array
  else
    time = time.first
    return array_older_than array, time
  end
end

#time_to_key(time, *resolution) ⇒ String

Convert a Time object to the respective Key TODO Refactoring



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# File 'lib/time_series.rb', line 168

def time_to_key time, *resolution
  if resolution.empty?
    return time.strftime("#{@prefix}%Y:%m:%d:%H:%M:%S")
  else
    resolution = resolution.first
    case resolution
      when :year   then return time.strftime("#{@prefix}%Y")
      when :month  then return time.strftime("#{@prefix}%Y:%m")
      when :day    then return time.strftime("#{@prefix}%Y:%m:%d")
      when :hour   then return time.strftime("#{@prefix}%Y:%m:%d:%H")
      when :minute then return time.strftime("#{@prefix}%Y:%m:%d:%H:%M")
      when :second then return time.strftime("#{@prefix}%Y:%m:%d:%H:%M:%S")
      else puts red "wrong resolution in time_to_key"
    end
  end
end

#year(time) ⇒ Object

def term_weights terms, factor

terms.each do |term, value|
  terms[term]=value*factor
end
return terms

end



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# File 'lib/time_series.rb', line 331

def year time;   time_to_key(time, :year).get end

#years(*time) ⇒ Array

Keys with year resolution



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# File 'lib/time_series.rb', line 269

def years *time
  array = keys.keep_if { |k| k.year? and k.persistant?}  
  if time.empty?
    return array
  else
    time = time.first
    return array_older_than array, time
  end  

end