erlang: uuid generator

问题:

What module/library do you use to generate uuid?

回答1:

For future googlers like myself, erlang-uuid from avtobiff works very simply.

回答2:

from http://github.com/travis/erlang-uuid

-module(uuid).
-export([v4/0, to_string/1, get_parts/1]).
-import(random).

v4() ->
    v4(random:uniform(math:pow(2, 48)) - 1, random:uniform(math:pow(2, 12)) - 1, random:uniform(math:pow(2, 32)) - 1, random:uniform(math:pow(2, 30)) - 1).
v4(R1, R2, R3, R4) ->
    <<R1:48, 4:4, R2:12, 2:2, R3:32, R4: 30>>.
to_string(U) ->
    lists:flatten(io_lib:format("~8.16.0b-~4.16.0b-~4.16.0b-~2.16.0b~2.16.0b-~12.16.0b", get_parts(U))).

get_parts(<<TL:32, TM:16, THV:16, CSR:8, CSL:8, N:48>>) ->
    [TL, TM, THV, CSR, CSL, N].

回答3:

Uuid generator from couchdb: http://svn.apache.org/viewvc/couchdb/trunk/src/couchdb/couch_uuids.erl

回答4:

I recommend using the ossp-uuid nif bindings for Erlang that has rebar support https://github.com/yrashk/erlang-ossp-uuid

ossp_uuid:make(v4, text)

回答5:

Why did you use round(math:pow(2, 48))? I think that 1 bsl 48 will work more quickly and code will not lose understanding.

回答6:

Try this one: https://github.com/afiskon/erlang-uuid-v4 The simplest implementation ever.

回答7:

If you don't need follow RFC 4122 you can use now/0 call to generate unique ID without external dependencies, because tuple, generated by now call is absolutely unique inside VM and unique with large probability beetween nodes.

回答8:

The one I wrote as an example of style and documentation -- based on the zillion recommendations I received from the kind-enough-to-be-mean folks on the Erlang list.

Library: https://gitlab.com/zxq9/zuuid

Docs: http://zxq9.com/projects/zuuid/docs/

PS: Huge thanks to the awesome folks of erlang-questions for taking the time to sharpshoot me on everything. The lib is far better for it.