SCRU64: Sortable, Clock-based, Realm-specifically Unique identifier

SCRU64 ID offers compact, time-ordered unique identifiers generated by distributed nodes. SCRU64 has the following features:

• ~62-bit non-negative integer storable as signed/unsigned 64-bit integer
• Sortable by generation time (as integer and as text)
• 12-digit case-insensitive textual representation (Base36)
• ~38-bit Unix epoch-based timestamp that ensures useful life until year 4261
• Variable-length node/machine ID and counter fields that share 24 bits

```rust // pass node ID through environment variable std::env::setvar("SCRU64NODE_SPEC", "42/8");

// generate a new identifier object let x = scru64::new(); println!("{x}"); // e.g. "0u2r85hm2pt3" println!("{}", x.to_u64()); // as a 64-bit unsigned integer

// generate a textual representation directly println!("{}", scru64::new_string()); // e.g. "0u2r85hm2pt4" ```

See [SCRU64 Specification] for details.

SCRU64's uniqueness is realm-specific, i.e., dependent on the centralized assignment of node ID to each generator. If you need decentralized, globally unique time-ordered identifiers, consider [SCRU128].

Crate features

Default features:

• std enables the primary new() and new_string() functions and configures generator::Scru64Generator with the system clock. Without std, this crate provides limited functionality available under no_std environments.

Optional features:

• serde enables serialization/deserialization via serde.
• tokio enables the async_tokio::new() and async_tokio::new_string() functions, the non-blocking counterpart of new() and new_string().

License

Licensed under the Apache License, Version 2.0.

See also

• docs.rs/scru64