postgres-eio

A native Postgres driver for OCaml 5 and Eio.

Documentation: hyphatech.github.io/postgres-eio

Features

• Secure by default: TLS, SCRAM-SHA-256 with channel binding and client certificates; a connection that crosses a network is encrypted unless its string says otherwise.
• Pool and failover: one pool serves every domain, across several hosts, with failover and load balancing.
• One round trip: statement caching, pipelining and batches.
• Streams: COPY in and out, and rows folded as they arrive, never buffered.
• LISTEN/NOTIFY: a listener that reconnects by itself and says so.
• Failures you can act on: each says whether the statement may have run, so a retry is never blind.

Install

opam repo add hypha https://github.com/hyphatech/opam-repository.git
opam install postgres-eio

(libraries postgres-eio eio_main)

Example

let () =
  Eio_main.run @@ fun env ->
  Eio.Switch.run @@ fun sw ->
  match Postgres_eio.Conninfo.of_string "postgres://app@localhost/shop" with
  | Error e -> prerr_endline e
  | Ok conninfo -> (
      match
        Postgres_eio.connect ~sw ~net:(Eio.Stdenv.net env)
          ~mono_clock:(Eio.Stdenv.mono_clock env)
          conninfo
      with
      | Error e -> prerr_endline (Postgres_eio.error_to_string e)
      | Ok conn ->
          (match
             Postgres_eio.query conn
               "select name from customers where country = $1"
               ~params:[ Some "GB" ] ~init:[] ~row:(fun names row ->
                 match row with [| Some name |] -> name :: names | _ -> names)
           with
          | Ok (names, _tag) -> List.iter print_endline names
          | Error e -> prerr_endline (Postgres_eio.error_to_string e));
          Postgres_eio.close conn)

Contributing

See AGENTS.md.

Licence

MIT, copyright Hypha Technologies Ltd. See LICENSE.