ksuid 
ksuid is a Go library that can generate and parse KSUIDs.
Install
go get -u github.com/segmentio/ksuid
What is a KSUID?
KSUID is for K-Sortable Unique IDentifier. It's a way to generate globally
unique IDs similar to RFC 4122 UUIDs, but contain a time component so they
can be "roughly" sorted by time of creation. The remainder of the KSUID is
randomly generated bytes.
Why use KSUIDs?
Distributed systems often require unique IDs. There are numerous solutions
out there for doing this, so why KSUID?
1. Sortable by Timestamp
Unlike the more common choice of UUIDv4, KSUIDs contain a timestamp component
that allows them to be roughly sorted by generation time. This is obviously not
a strong guarantee as it depends on wall clocks, but is still incredibly useful
in practice.
2. No Coordination Required
Snowflake IDs[1] and derivatives require coordination, which significantly
increases the complexity of implementation and creates operations overhead.
While RFC 4122 UUIDv1s do have a time component, there aren't enough bytes of
randomness to provide strong protections against duplicate ID generation.
KSUIDs use 128-bits of pseudorandom data, which provides a 64-times larger
number space than the 122-bits in the well-accepted RFC 4122 UUIDv4 standard.
The additional timestamp component drives down the extremely rare chance of
duplication to the point of near physical infeasibility, even assuming extreme
clock skew (> 24-hours) that would cause other severe anomalies.
3. Lexographically Sortable, Portable Representations
The binary and string representations are lexicographically sortable, which
allows them to be dropped into systems which do not natively support KSUIDs
and retain their k-sortable characteristics.
The string representation is that it is base62-encoded, so that they can "fit"
anywhere alphanumeric strings are accepted.
How do they work?
KSUIDs are 20-bytes: a 32-bit unsigned integer UTC timestamp and a 128-bit
randomly generated payload. The timestamp uses big-endian encoding, to allow
lexicographic sorting. The timestamp epoch is adjusted to March 5th, 2014,
providing over 100 years of useful life starting at UNIX epoch + 14e8. The
payload uses a cryptographically-strong pseudorandom number generator.
The string representation is fixed at 27-characters encoded using a base62
encoding that also sorts lexicographically.
Command Line Tool
This package comes with a simple command-line tool ksuid. This tool can
generate KSUIDs as well as inspect the internal components for debugging
purposes.
Usage examples
Generate 4 KSUID
$ ./ksuid -n 4
0ujsszwN8NRY24YaXiTIE2VWDTS
0ujsswThIGTUYm2K8FjOOfXtY1K
0ujssxh0cECutqzMgbtXSGnjorm
0ujsszgFvbiEr7CDgE3z8MAUPFt
Inspect the components of a KSUID
Using the inspect formatting on just 1 ksuid:
$ ./ksuid -f inspect $(./ksuid)
REPRESENTATION:
String: 0ujtsYcgvSTl8PAuAdqWYSMnLOv
Raw: 0669F7EFB5A1CD34B5F99D1154FB6853345C9735
COMPONENTS:
Time: 2017-10-09 21:00:47 -0700 PDT
Timestamp: 107608047
Payload: B5A1CD34B5F99D1154FB6853345C9735
Using the template formatting on 4 ksuid:
$ ./ksuid -f template -t '{{ .Time }}: {{ .Payload }}' $(./ksuid -n 4)
2017-10-09 21:05:37 -0700 PDT: 304102BC687E087CC3A811F21D113CCF
2017-10-09 21:05:37 -0700 PDT: EAF0B240A9BFA55E079D887120D962F0
2017-10-09 21:05:37 -0700 PDT: DF0761769909ABB0C7BB9D66F79FC041
2017-10-09 21:05:37 -0700 PDT: 1A8F0E3D0BDEB84A5FAD702876F46543
Generate detailed versions of new KSUID
Generate a new KSUID with the corresponding time using the time formatting:
$ go run cmd/ksuid/main.go -f time -v
0uk0ava2lavfJwMceJOOEFXEDxl: 2017-10-09 21:56:00 -0700 PDT
Generate 4 new KSUID with details using template formatting:
$ ./ksuid -f template -t '{ "timestamp": "{{ .Timestamp }}", "payload": "{{ .Payload }}", "ksuid": "{{.String}}"}' -n 4
{ "timestamp": "107611700", "payload": "9850EEEC191BF4FF26F99315CE43B0C8", "ksuid": "0uk1Hbc9dQ9pxyTqJ93IUrfhdGq"}
{ "timestamp": "107611700", "payload": "CC55072555316F45B8CA2D2979D3ED0A", "ksuid": "0uk1HdCJ6hUZKDgcxhpJwUl5ZEI"}
{ "timestamp": "107611700", "payload": "BA1C205D6177F0992D15EE606AE32238", "ksuid": "0uk1HcdvF0p8C20KtTfdRSB9XIm"}
{ "timestamp": "107611700", "payload": "67517BA309EA62AE7991B27BB6F2FCAC", "ksuid": "0uk1Ha7hGJ1Q9Xbnkt0yZgNwg3g"}
Display the detailed version of a new KSUID:
$ ./ksuid -f inspect
REPRESENTATION:
String: 0ujzPyRiIAffKhBux4PvQdDqMHY
Raw: 066A029C73FC1AA3B2446246D6E89FCD909E8FE8
COMPONENTS:
Time: 2017-10-09 21:46:20 -0700 PDT
Timestamp: 107610780
Payload: 73FC1AA3B2446246D6E89FCD909E8FE8