Class: VIN::Config

Inherits:
Object
  • Object
show all
Defined in:
lib/vin/config.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(custom_epoch: nil, timestamp_bits: nil, logical_shard_id_bits: nil, data_type_bits: nil, sequence_bits: nil, logical_shard_id_range: nil) ⇒ Config

Returns a new instance of Config.



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# File 'lib/vin/config.rb', line 21

def initialize(
  custom_epoch: nil,
  timestamp_bits: nil,
  logical_shard_id_bits: nil,
  data_type_bits: nil,
  sequence_bits: nil,
  logical_shard_id_range: nil
)
  @custom_epoch = custom_epoch || ENV.fetch("VIN_CUSTOM_EPOCH").to_i
  @timestamp_bits = timestamp_bits || ENV.fetch("VIN_TIMESTAMP_BITS").to_i
  @logical_shard_id_bits = logical_shard_id_bits || ENV.fetch("VIN_LOGICAL_SHARD_ID_BITS").to_i
  @data_type_bits = data_type_bits || ENV.fetch("VIN_DATA_TYPE_BITS").to_i
  @sequence_bits = sequence_bits || ENV.fetch("VIN_SEQUENCE_BITS").to_i
  @logical_shard_id_range = logical_shard_id_range || fetch_allowed_range!
end

Instance Attribute Details

#custom_epoch ⇒ Object (readonly)

Expressed in milliseconds.



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# File 'lib/vin/config.rb', line 4

def custom_epoch
  @custom_epoch
end

#data_type_bits ⇒ Object (readonly)

For instance, 9 bits gives us 512 different data types.



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# File 'lib/vin/config.rb', line 13

def data_type_bits
  @data_type_bits
end

#logical_shard_id_bits ⇒ Object (readonly)

For instance, 3 bits gives us 8 logical shards, which means we can have 8 different servers generating ids.



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# File 'lib/vin/config.rb', line 10

def logical_shard_id_bits
  @logical_shard_id_bits
end

#logical_shard_id_range ⇒ Object (readonly)

Defaults to allowing all logical shard ids to be generated by this server.



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# File 'lib/vin/config.rb', line 19

def logical_shard_id_range
  @logical_shard_id_range
end

#sequence_bits ⇒ Object (readonly)

For instance, 11 bits gives us 2048 ids per millisecond per logical shard.



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# File 'lib/vin/config.rb', line 16

def sequence_bits
  @sequence_bits
end

#timestamp_bits ⇒ Object (readonly)

For instance, 40 bits gives us 1099511627776 milliseconds, or 34.8 years. Enough time to last us until 2057, enough time for any of us to retire.



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# File 'lib/vin/config.rb', line 7

def timestamp_bits
  @timestamp_bits
end

Instance Method Details

#data_type_allowed_range ⇒ Object 



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# File 'lib/vin/config.rb', line 57

def data_type_allowed_range
  @data_type_allowed_range ||= (min_data_type..max_data_type)
end

#data_type_shift ⇒ Object 



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# File 'lib/vin/config.rb', line 69

def data_type_shift
  @data_type_shift ||= sequence_bits
end

#fetch_allowed_range! ⇒ Object 



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# File 'lib/vin/config.rb', line 81

def fetch_allowed_range!
  range = Range.new(
    ENV.fetch("VIN_LOGICAL_SHARD_ID_RANGE_MIN", 0).to_i,
    ENV.fetch("VIN_LOGICAL_SHARD_ID_RANGE_MAX", 0).to_i,
  )
  # rubocop:disable Style/BitwisePredicate
  unless (logical_shard_id_allowed_range.to_a & range.to_a) == range.to_a
    raise(ArgumentError, "VIN_LOGICAL_SHARD_ID_RANGE_MIN and VIN_LOGICAL_SHARD_ID_RANGE_MAX env vars compose a range outside the allowed range of #{logical_shard_id_allowed_range} defined by the number of bits in VIN_LOGICAL_SHARD_ID_BITS env var.")
  end
  # rubocop:enable Style/BitwisePredicate
  range
end

#logical_shard_id_allowed_range ⇒ Object 



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# File 'lib/vin/config.rb', line 45

def logical_shard_id_allowed_range
  @logical_shard_id_allowed_range ||= (min_logical_shard_id..max_logical_shard_id)
end

#logical_shard_id_shift ⇒ Object 



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# File 'lib/vin/config.rb', line 73

def logical_shard_id_shift
  @logical_shard_id_shift ||= (sequence_bits + data_type_bits)
end

#max_data_type ⇒ Object 



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# File 'lib/vin/config.rb', line 53

def max_data_type
  @max_data_type ||= ~(-1 << data_type_bits)
end

#max_logical_shard_id ⇒ Object 



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# File 'lib/vin/config.rb', line 41

def max_logical_shard_id
  @max_logical_shard_id ||= ~(-1 << logical_shard_id_bits)
end

#max_sequence ⇒ Object 



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# File 'lib/vin/config.rb', line 61

def max_sequence
  @max_sequence ||= ~(-1 << sequence_bits)
end

#min_data_type ⇒ Object 



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# File 'lib/vin/config.rb', line 49

def min_data_type
  0
end

#min_logical_shard_id ⇒ Object 



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# File 'lib/vin/config.rb', line 37

def min_logical_shard_id
  0
end

#sequence_shift ⇒ Object 



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# File 'lib/vin/config.rb', line 65

def sequence_shift
  0
end

#timestamp_shift ⇒ Object 



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# File 'lib/vin/config.rb', line 77

def timestamp_shift
  @timestamp_shift ||= (sequence_bits + data_type_bits + logical_shard_id_bits)
end