KSUID: A Comprehensive Overview
KSUID is a high-performance Go library designed to generate and parse a special type of globally unique identifier known as a KSUID. Intended for systems that require consistently sortable unique identifiers, KSUID stands out because of its intrinsically generated timestamp component. The KSUID library is widely recognized for its efficiency and reliability, making it a reference implementation in its space.
Installation
To incorporate KSUID into a project, install it using the following Go command:
go get -u github.com/segmentio/ksuid
What is a KSUID?
KSUID stands for K-Sortable Unique Identifier. It is akin to the universally known RFC 4122 UUID but crafted to automatically sort by the generation timestamp. This means that sorting KSUIDs using tools like UNIX’s sort will naturally arrange them by the order of creation.
Why Choose KSUIDs?
KSUIDs offer several distinctive advantages:
- Time-Based Natural Ordering: They inherently sort by the time of generation.
- Collision-Free and Independent: KSUIDs function without risk of collisions, need for external coordination, or added dependencies.
- High Portability: They have easily transferable representations across different systems and formats.
These features make KSUIDs a compelling choice for projects requiring ease of use, reliability, and portability. Many projects have specifically adopted KSUIDs because their text representations are straightforward to use and compatible with various systems.
1. Naturally Ordered by Generation Time
While UUIDv4 provides a popular solution for generating unique identifiers, it lacks a time component, which makes it impossible to sort by generation time. KSUID, however, incorporates a timestamp, allowing it to be sorted by creation time. This feature is especially advantageous for indexing and managing database records chronologically.
2. Collision-Free, Coordination-Free, Dependency-Free
RFC 4122 UUIDv1 includes a timestamp too, but it doesn’t allocate enough randomness to avoid potential collisions. KSUID eliminates this concern by utilizing 128 bits of random data, surpassing the 122 bits provided by UUIDv4. Additionally, KSUIDs do not require coordination to guarantee uniqueness, simplifying deployment.
3. Highly Portable Representations
The binary and text forms of KSUIDs are designed to be readily sorted. The text version uses a base62 encoding, enabling flexible usage in nearly any environment that supports string data. Its structure prevents accidental truncation or parsing errors during software handling.
How Do KSUIDs Function?
Binary KSUIDs are composed of 20 bytes: a 32-bit UTC timestamp for ordering and a 128-bit random component for uniqueness. The timestamp is formatted using big-endian encoding to ensure proper sorting. It is calibrated to start from May 13, 2014, lasting over a century. The random component is created using a secure pseudorandom number generator, ensuring both uniqueness and security.
The text representation of KSUIDs is consistently 27 characters long and encoded in base62, ensuring it retains its sort order.
High Performance
KSUIDs are specifically optimized for performance-critical use cases. By eliminating excessive overhead, KSUIDs offer fast and efficient operations. The library’s API is also designed to minimize memory allocations, enhancing performance in intensive environments. Even under high concurrency, KSUIDs maintain their speed and reliability through thoughtful implementation.
Battle-Tested in Production
The KSUID library has been extensively vetted in production environments at Segment and numerous other high-scale systems, where it has generated trillions of identifiers. This extensive use underscores its reliability and efficiency across various demanding scenarios.
Integration with Existing Systems
KSUID can seamlessly integrate with other libraries and systems, implementing numerous standard interfaces like Stringer, database/sql.Scanner, and JSON-friendly methods, which facilitate its widespread adoption and adaptability.
Command Line Tool
KSUID comes with a command-line tool for generating KSUIDs and examining their components. This feature is particularly useful for scripting and automation tasks in development environments. Install it using:
$ go install github.com/segmentio/ksuid/cmd/ksuid
CLI Usage Examples
- Generate a KSUID:
ksuid - Generate Multiple KSUIDs:
ksuid -n 4 - Inspect KSUID Components:
ksuid -f inspect <ksuid>
OrNil Functions
KSUID provides OrNil functions to simplify error handling during parsing operations, returning nil if conversion fails. These functions streamline code paths where developers are confident of KSUID validity.
Implementations in Other Languages
For users across diverse programming environments, KSUID has been implemented in multiple languages, including Python, Ruby, Java, Rust, .NET, and more.
Licensing
The KSUID source code is available under the MIT License, promoting open use and adaptation in various software projects.