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Versions: 28
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Stored size: 1.98 KB
Contents
require 'prometheus/client/helper/mmaped_file'
require 'prometheus/client/helper/plain_file'
require 'prometheus/client'
module Prometheus
module Client
class ParsingError < StandardError
end
# A dict of doubles, backed by an mmapped file.
#
# The file starts with a 4 byte int, indicating how much of it is used.
# Then 4 bytes of padding.
# There's then a number of entries, consisting of a 4 byte int which is the
# size of the next field, a utf-8 encoded string key, padding to an 8 byte
# alignment, and then a 8 byte float which is the value.
class MmapedDict
attr_reader :m, :used, :positions
def self.read_all_values(f)
Helper::PlainFile.new(f).entries.map do |data, encoded_len, value_offset, _|
encoded, value = data.unpack(format('@4A%d@%dd', encoded_len, value_offset))
[encoded, value]
end
end
def initialize(m)
@mutex = Mutex.new
@m = m
# @m.mlock # TODO: Ensure memory is locked to RAM
@positions = {}
read_all_positions.each do |key, pos|
@positions[key] = pos
end
rescue StandardError => e
raise ParsingError, "exception #{e} while processing metrics file #{path}"
end
def read_value(key)
@m.fetch_entry(@positions, key, 0.0)
end
def write_value(key, value)
@m.upsert_entry(@positions, key, value)
end
def path
@m.filepath if @m
end
def close
@m.sync
@m.close
rescue TypeError => e
Prometheus::Client.logger.warn("munmap raised error #{e}")
end
private
def init_value(key)
@m.add_entry(@positions, key, 0.0)
end
# Yield (key, pos). No locking is performed.
def read_all_positions
@m.entries.map do |data, encoded_len, _, absolute_pos|
encoded, = data.unpack(format('@4A%d', encoded_len))
[encoded, absolute_pos]
end
end
end
end
end
Version data entries
28 entries across 28 versions & 1 rubygems