Awskit

Package Split

Awskit follows a Cohttp-style package split. Install only the runtime adapter you need.

• awskit — pure AWS core: credentials, regions, endpoints, signing, retries, request/response types, errors, and the runtime module type
• awskit-unix — Unix helpers for clocks, environment variables, shared AWS credentials, and config files
• awskit-lwt — generic Lwt runtime adapter over a caller-supplied Cohttp Lwt client
• awskit-lwt-unix — ready-to-use Lwt + Unix runtime adapter
• awskit-eio — ready-to-use direct-style Eio runtime adapter
• awskit-s3 — pure AWS S3 core: buckets, objects, multipart upload, presigned URLs, policies, and endpoint resolution
• awskit-s3-sim — deterministic in-memory S3 implementation for tests
• awskit-s3-lwt — S3 adapter over the generic Awskit Lwt runtime
• awskit-s3-lwt-unix — ready-to-use S3 client for Lwt + Unix
• awskit-s3-eio — ready-to-use S3 client for Eio

The core awskit and awskit-s3 packages do not depend on Unix, Eio, Lwt, or Cohttp runtime packages. awskit-s3-sim is for tests and does not perform HTTP requests. Adapter packages carry runtime dependencies.

Quick Start

For Eio applications:

opam install awskit-s3-eio eio_main

For Lwt + Unix applications:

opam install awskit-s3-lwt-unix

Eio

open Eio.Std

let run env =
  Switch.run @@ fun sw ->
  let credentials =
    Awskit.Credentials.create_exn
      ~access_key_id:"AKIAIOSFODNN7EXAMPLE"
      ~secret_access_key:"wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
      ()
  in
  let region = Awskit.Region.of_string_exn "us-east-1" in
  let s3 = Awskit_s3_eio.create ~sw ~env ~region ~credentials () in
  match
    Awskit_s3_eio.Object.put_string s3
      ~bucket:"my-bucket"
      ~key:"hello.txt"
      "Hello, S3!"
  with
  | Ok _ -> ()
  | Error error -> Fmt.epr "%a@." Awskit_s3.Error.pp error

Lwt + Unix

let run () =
  let open Lwt.Syntax in
  match Awskit_s3_lwt_unix.create () with
  | Error error ->
      Lwt_io.eprintf "%a\n" Awskit_s3.Error.pp error
  | Ok s3 ->
      let* result =
        Awskit_s3_lwt_unix.Object.get_as_string s3
          ~bucket:"my-bucket"
          ~key:"hello.txt"
          ~max_bytes:1_048_576L
          ()
      in
      match result with
      | Ok (_info, body) -> Lwt_io.printl body
      | Error error -> Lwt_io.eprintf "%a\n" Awskit_s3.Error.pp error

When arguments are omitted, Unix adapters read standard AWS configuration sources such as AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN, AWS_REGION, AWS_DEFAULT_REGION, AWS_PROFILE, AWS_SHARED_CREDENTIALS_FILE, and AWS_CONFIG_FILE. The Lwt Unix runtime also supports ECS/container and EC2 instance metadata credential providers.

Endpoint overrides are explicit. S3-specific endpoint and addressing options are exposed by the S3 adapter create functions.

Package Documentation

• awskit — pure AWS core and runtime adapters
• awskit guides — credentials, endpoints, signing, errors, retries, and adapter selection
• awskit-s3 — AWS S3 objects, buckets, multipart upload, presigned URLs, and policies
• awskit-s3-sim — deterministic in-memory S3 tests
• awskit-s3 guides — S3 operations in depth