Snowcloud is a service for generating unique, time-ordered, 64-bit IDs across distributed worker processes. This format is commonly called "snowflake" IDs, and is used by Twitter and Discord.
| Timestamp | Worker ID | Increment |
|---|---|---|
| 42 bits | 10 bits | 12 bits |
| milliseconds since Jan 1, 2020 | allocated by delegator | incremented by generator |
A Snowcloud deployment consists of a delegator and many generators.
The delegator (located in snowcloud/delegator.py, run with e.g. python3 -m snowcloud.delegator) keeps track of assigning worker IDs to different generator processes. It uses Redis to keep track of a pool of worker IDs. It then allows clients to register for a worker ID or renew their existing worker ID.
Generators obtain a worker ID from the delegator and use it to generate their own Snowflake IDs. These can be integrated into Flask applications using the snowcloud.flask_ext module.
An example Flask server is located in snowcloud/server.py. However, more commonly, the Flask application would use the Snowflake ID internally instead. For instance, it could generate a Snowflake ID to use as the primary key column whenever it inserts a new row into the database.