Snowflake and SCRU64 layouts — id

A layout says how a 64-bit identifier splits into a time, node fields and a sequence. It is data: the time field's bits, unit and epoch, the node fields with their widths in order, the sequence width, and whether the top bit is a sign bit. zuid cannot discover a Snowflake's layout from the number, so its fields are readable only when the layout is given.

Usage

id_layout(
  name = NULL,
  epoch = NULL,
  node_bits = NULL,
  time = NULL,
  fields = NULL,
  sequence = NULL,
  sign_bit = TRUE
)

# S3 method for class 'zuid_layout'
print(x, ...)

# S3 method for class 'zuid_layout'
format(x, ...)

Arguments

name: A built-in layout, or NULL for a custom one.
epoch: For "sonyflake" (required) or a custom layout, the time the time field counts from: a POSIXct or milliseconds since 1970.
node_bits: For "scru64", the node id's bits, 1 to 23.
time: For a custom layout, list(bits =, unit =, epoch =), unit one of "ms", "10ms", "256ms" and "s".
fields: For a custom layout, the node fields as a named list or vector of widths, most significant first.
sequence: For a custom layout, the sequence's bits.
sign_bit: For a custom layout, whether the top bit is reserved.
x: A layout.
...: Unused.

Value

A zuid_layout.

Details

The built-in layouts:

Name	Time	Node fields	Sequence
`twitter`	41 bits, ms, from 2010-11-04T01:42:54.657Z	`datacenter` 5, `worker` 5	12
`discord`	42 bits, ms, from 2015-01-01	`worker` 5, `process` 5	12
`instagram`	41 bits, ms, from 2011-08-24T21:07:01.721Z	`shard` 13	10
`sonyflake`	39 bits, 10 ms, from `epoch`	`machine` 16, after the sequence	8
`scru64`	39 bits, 256 ms, from 1970	`node` of `node_bits`	24 - `node_bits`

Twitter, Sonyflake and SCRU64 keep the top bit as a sign bit; Discord and Instagram use all 64 bits. Sonyflake's reference has changed its default start time between releases, so epoch is required for it.

A custom layout gives time, fields, sequence and sign_bit. The bits must add up to 64, or 63 with the sign bit, and each part must have fewer than 54 bits, so that it reads exactly as a double. The sequence has at most 31 bits, so that id_fields() returns it as an integer.

Examples

id_layout("twitter")
#> <zuid_layout twitter>
#> | sign 1 | time 41 | datacenter 5 | worker 5 | sequence 12 |
#> time: ms units from 2010-11-04T01:42:54.657Z
id_layout("scru64", node_bits = 8)
#> <zuid_layout scru64>
#> | sign 1 | time 39 | node 8 | sequence 16 |
#> time: 256ms units from 1970-01-01T00:00:00.000Z
id_layout(
  time = list(bits = 41, unit = "ms", epoch = 0),
  fields = list(worker = 10),
  sequence = 12
)
#> <zuid_layout custom>
#> | sign 1 | time 41 | worker 10 | sequence 12 |
#> time: ms units from 1970-01-01T00:00:00.000Z