# Bigflake
[](https://travis-ci.org/stevedomin/bigflake)
128-bit, k-ordered, conflict-free IDs in Elixir.
This implementation draws heavily on [Matt Heath's Kāla](https://github.com/mattheath/kala) project, as well as the
[Boudary's flake](https://github.com/boundary/flake).
The IDs it generates consist of:
- timestamp (64-bit): milliseconds since epoch
- worker id (48-bit): an integer or the MAC-address from a device
- sequence number (16-bit): an integer, incremented for each ID requested on the same millisecond
## Installation
This package can be installed by:
1. Adding bigflake to your list of dependencies in `mix.exs`:
def deps do
[{:bigflake, "~> 0.3.0"}]
end
2. Ensuring bigflake is started before your application:
def application do
[applications: [:bigflake]]
end
## Usage
```elixir
# generate an id
iex(1)> Bigflake.mint()
{:ok, 26868369774934248202951567081472}
```
You can configure Bigflake to use an integer or a 48-bit MAC address as a worker id.
By default it will use the MAC address of the first device it finds.
```elixir
# config/config.exs
config :bigflake, worker_id: :en1
```
## Using with Ecto
There are several ways you can use Bigflake ids as primary keys in your Ecto schemas.
### Base62-encoded string
```elixir
defmodule Ecto.Bigflake.Base62 do
@behaviour Ecto.Type
def type, do: :string
def cast(string) when is_binary(string), do: {:ok, string}
def cast(_), do: :error
def dump(string) when is_binary(string), do: {:ok, string}
def dump(_), do: :error
def load(string) when is_binary(string), do: {:ok, string}
def generate do
{:ok, id} = Bigflake.mint(:base62, length: 25)
id
end
def autogenerate do
generate()
end
end
defmodule User do
use Ecto.Schema
@primary_key {:id, Ecto.Bigflake.Base62, autogenerate: true}
schema "users" do
field :name, :string
field :email, :string
timestamps
end
end
# priv/repo/migrations/create_user.exs
defmodule Repo.Migrations.CreateUser do
use Ecto.Migration
def change do
create table(:users, primary_key: false) do
add :id, :string, size: 25, primary_key: true
add :name, :string
add :email, :string
timestamps
end
end
end
```
### UUID
```elixir
# This module is entirely based off Ecto.UUID, with the generation functions changed.
# (https://github.com/elixir-lang/ecto/blob/master/lib/ecto/uuid.ex)
defmodule Ecto.Bigflake.UUID do
@behaviour Ecto.Type
def type, do: :uuid
def cast(<< _::64, ?-, _::32, ?-, _::32, ?-, _::32, ?-, _::96 >> = u), do: {:ok, u}
def cast(_), do: :error
def dump(<< a1, a2, a3, a4, a5, a6, a7, a8, ?-,
b1, b2, b3, b4, ?-,
c1, c2, c3, c4, ?-,
d1, d2, d3, d4, ?-,
e1, e2, e3, e4, e5, e6, e7, e8, e9, e10, e11, e12 >>) do
try do
<< d(a1)::4, d(a2)::4, d(a3)::4, d(a4)::4,
d(a5)::4, d(a6)::4, d(a7)::4, d(a8)::4,
d(b1)::4, d(b2)::4, d(b3)::4, d(b4)::4,
d(c1)::4, d(c2)::4, d(c3)::4, d(c4)::4,
d(d1)::4, d(d2)::4, d(d3)::4, d(d4)::4,
d(e1)::4, d(e2)::4, d(e3)::4, d(e4)::4,
d(e5)::4, d(e6)::4, d(e7)::4, d(e8)::4,
d(e9)::4, d(e10)::4, d(e11)::4, d(e12)::4 >>
catch
:error -> :error
else
binary ->
{:ok, %Ecto.Query.Tagged{type: :uuid, value: binary}}
end
end
def dump(_), do: :error
@compile {:inline, d: 1}
defp d(?0), do: 0
defp d(?1), do: 1
defp d(?2), do: 2
defp d(?3), do: 3
defp d(?4), do: 4
defp d(?5), do: 5
defp d(?6), do: 6
defp d(?7), do: 7
defp d(?8), do: 8
defp d(?9), do: 9
defp d(?A), do: 10
defp d(?B), do: 11
defp d(?C), do: 12
defp d(?D), do: 13
defp d(?E), do: 14
defp d(?F), do: 15
defp d(?a), do: 10
defp d(?b), do: 11
defp d(?c), do: 12
defp d(?d), do: 13
defp d(?e), do: 14
defp d(?f), do: 15
defp d(_), do: throw(:error)
def load(<<_::128>> = uuid) do
{:ok, encode(uuid)}
end
def load(<<_::64, ?-, _::32, ?-, _::32, ?-, _::32, ?-, _::96>> = string) do
raise "trying to load string UUID as Ecto.Bigflake.UUID: #{inspect string}. " <>
"Maybe you wanted to declare :uuid as your database field?"
end
def load(%Ecto.Query.Tagged{type: :uuid, value: uuid}) do
{:ok, encode(uuid)}
end
def load(_), do: :error
def generate do
bingenerate() |> encode()
end
def bingenerate() do
{:ok, id} = Bigflake.mint()
<<id::128-integer>>
end
def autogenerate do
%Ecto.Query.Tagged{type: :uuid, value: bingenerate()}
end
defp encode(<<u0::32, u1::16, u2::16, u3::16, u4::48>>) do
hex_pad(u0, 8) <> "-" <>
hex_pad(u1, 4) <> "-" <>
hex_pad(u2, 4) <> "-" <>
hex_pad(u3, 4) <> "-" <>
hex_pad(u4, 12)
end
defp hex_pad(hex, count) do
hex = Integer.to_string(hex, 16)
lower(hex, :binary.copy("0", count - byte_size(hex)))
end
defp lower(<<h, t::binary>>, acc) when h in ?A..?F,
do: lower(t, acc <> <<h + 32>>)
defp lower(<<h, t::binary>>, acc),
do: lower(t, acc <> <<h>>)
defp lower(<<>>, acc),
do: acc
end
defmodule User do
use Ecto.Schema
@primary_key {:id, Ecto.Bigflake.UUID, autogenerate: true}
schema "users" do
field :name, :string
field :email, :string
timestamps
end
end
# priv/repo/migrations/create_user.exs
defmodule Repo.Migrations.CreateUser do
use Ecto.Migration
def change do
create table(:users, primary_key: false) do
add :id, :uuid, primary_key: true
add :name, :string
add :email, :string
timestamps
end
end
end
```
## Benchmarks
(Results from a MBP i7 2.5Ghz)
```
mint ids 1000000 2.69 µs/op
mint base62 ids 500000 6.64 µs/op
```
## LICENSE
See [LICENSE](https://github.com/stevedomin/bigflake/blob/master/LICENSE)
