class Snowflake

• Snowflake
• Reference
• Object

Overview

The Snowflake class implements a Snowflake ID generator, which is designed to generate unique, time-based identifiers using a 64-bit structure. These identifiers consist of a timestamp component, a machine or process ID, and a sequence number to ensure uniqueness within the same millisecond.

The 64-bit ID is composed as follows:

• 1 bit is unused (always set to 0).
• 41 bits are used to store the milliseconds since a custom epoch, allowing for 69 years of unique timestamps.
• 10 bits are allocated for the machine ID, allowing up to 1024 machines or processes.
• 12 bits are used for the sequence number, allowing up to 4096 IDs to be generated per millisecond, per machine.

This implementation uses the Twitter epoch of 1288834974657 milliseconds since the Unix epoch (1970-01-01 00:00:00 UTC), which corresponds to November 4, 2010, 01:42:54.657 UTC. This epoch is the reference point from which all timestamps in Snowflake IDs are calculated.

Usage:

machine_id = 1_u64 # Assign a unique machine/process ID
generator = Snowflake.new(machine_id)
snowflake_id = generator.generate_id
puts snowflake_id

# To convert a Snowflake ID back to a UTC timestamp
utc_time = Snowflake.id_to_utc(snowflake_id)
puts utc_time

NOTE The machine ID must be unique across all instances of the generator to ensure the uniqueness of generated IDs.

Used resources:

• https://developer.twitter.com/en/docs/twitter-ids
• https://en.wikipedia.org/wiki/Snowflake_ID
• https://keeplearning.dev/twitter-snowflake-approach-is-cool-3156f78017cb

Defined in:

snowflake.cr

Constant Summary

EPOCH = 1288834974657_i64

MACHINE_ID_BITS = 10

MACHINE_ID_SHIFT = SEQUENCE_BITS

MAX_MACHINE_ID = (1 << MACHINE_ID_BITS) - 1

Maximum values

MAX_SEQUENCE = (1 << SEQUENCE_BITS) - 1

SEQUENCE_BITS = 12

TIMESTAMP_BITS = 41

Constants for bit lengths

TIMESTAMP_SHIFT = MACHINE_ID_BITS + SEQUENCE_BITS

Bit shifts

VERSION = {{ (`shards version /srv/crystaldoc.info/github-mamantoha-snowflake-v0.1.0/src`).chomp.stringify }}

Constructors

• .new(machine_id : UInt64)

Class Method Summary

• .id_to_utc(snowflake_id : UInt64) : Time

  Converts a given snowflake_id back to the UTC timestamp representing

Instance Method Summary

• #generate_id : UInt64

  Generates a unique Snowflake ID based on the current time, machine ID, and an internal sequence.

Constructor Detail

Class Method Detail

Instance Method Detail