[ANN] Protobuf 0.0.2

Protobuf is an Ocaml library for communicating with Google's protobuf format. It provides a method for writing parsers and builders. There is no protoc support, yet and writing it is not a top goal right now. Protobuf is meant to be fairly lightweight and straight forward to use. The only other Protobuf support for Ocaml I am aware of is through piqi, however that was too heavy for my needs.

Protobuf is meant to be very low level, mostly dealing with representation of values and not semantics. For example, the fixed32 and sfixed32 values are both parsed as Int32.t's. Dealing with being signed or not is left up to the user.

The source code can be viewed here. Protobuf is in opam, to install it opam install protobuf.

The hope is that parsers and builders look reasonably close to the .proto files such that translation is straight forward, at least until protoc support is added. This is an early release and, without a doubt, has bugs in it please submit pull requests and issues.

https://github.com/orbitz/ocaml-protobuf/tree/0.0.2/

Examples

The best collection of examples right now is the tests. An example from the file:

let simple =
  P.int32 1 >>= P.return

let complex =
  P.int32 1           >>= fun num ->
  P.string 2          >>= fun s ->
  P.embd_msg 3 simple >>= fun emsg ->
  P.return (num, s, emsg)

let run_complex str =
  let open Result.Monad_infix in
  P.State.create (Bitstring.bitstring_of_string str)
  >>= fun s ->
  P.run complex s

The builder for this message looks like:

let build_simple i =
  let open Result.Monad_infix in
  let b = B.create () in
  B.int32 b 1 i >>= fun () ->
  Ok (B.to_string b)

let build_complex (i1, s, i2) =
  let open Result.Monad_infix in
  let b = B.create () in
  B.int32 b 1 i1                 >>= fun () ->
  B.string b 2 s                 >>= fun () ->
  B.embd_msg b 3 i2 build_simple >>= fun () ->
  Ok (B.to_string b)

[ANN] ocaml-vclock - 0.0.0

I ported some Erlang vector clock code to Ocaml for fun and learning. It's not well tested and it hasn't any performance optimizations. I'm not ready yet but I have some projects in mind to use it so it will likely get fleshed out more.

Vector clocks are a system for determining the partial ordering of events in a distributed environment. You can determine if one value is the ancestor of another, equal, or was concurrently updated. It is one mechanism that distributed databases, such as Riak, use to automatically resolve some conflicts in data while maintaining availability.

The vector clock implementation allows for user defined site id type. It also allows metadata to be encoded in the site id, which is useful if you want your vector clock to be prunable by encoding timestamps in it.

The repo can be found here. If you'd like to learn more about vector clocks read the wikipedia page here. The Riak website also has some content on vector clocks here.