ReqS3

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Req plugin for Amazon S3 and S3-compatible services.

ReqS3 handles a custom s3:// url scheme. Example requests are:

# list buckets
Req.get!(req, url: "s3://")

# list objects
Req.get!(req, url: "s3://#{bucket}")

# get object
Req.get!(req, url: "s3://#{bucket}/#{key}")

# put object
Req.put!(req, url: "s3://#{bucket}/#{key}")

The responses for listing buckets and objects are automatically decoded.

Usage 

Mix.install([
  {:req, "~> 0.5.0"},
  {:req_s3, "~> 0.2.3"}
])

req = Req.new() |> ReqS3.attach()

Req.get!(req, url: "s3://ossci-datasets").body
#=>
# %{
#   "ListBucketResult" => %{
#     "Contents" => [
#       %{"Key" => "mnist/", ...},
#       %{"Key" => "mnist/t10k-images-idx3-ubyte.gz", ...},
#       ...
#     ],
#     "Name" => "ossci-datasets",
#     ...
#   }
# }

body = Req.get!(req, url: "s3://ossci-datasets/mnist/t10k-images-idx3-ubyte.gz").body
<<_::32, n_images::32, n_rows::32, n_cols::32, _body::binary>> = body
{n_images, n_rows, n_cols}
#=> {10_000, 28, 28}

Examples

Pre-signing

ReqS3 can be used to presign URLs:

options = [
  access_key_id: System.fetch_env!("AWS_ACCESS_KEY_ID"),
  secret_access_key: System.fetch_env!("AWS_SECRET_ACCESS_KEY")
]

req = Req.new() |> ReqS3.attach(aws_sigv4: options)
%{status: 200} = Req.put!(req, url: "s3://bucket1/key1", body: "Hello, World!")

presigned_url = ReqS3.presign_url([bucket: "bucket1", key: "key1"] ++ options)
#=> "https://bucket1.s3.amazonaws.com/key1?X-Amz-Algorithm=AWS4-HMAC-SHA256&..."

Req.get!(presigned_url).body
#=> "Hello, World!"

and form uploads:

form = ReqS3.presign_form([bucket: "bucket1", key: "key1"] ++ options)
%{status: 204} = Req.post!(form.url, form_multipart: [file: "Hello, World!"] ++ form.fields)

Req.get!(presigned_url).body
#=> "Hello, World!"

Environment Variables

ReqS3 supports the following standardised system environment variables:

  • AWS_ACCESS_KEY_ID

  • AWS_SECRET_ACCESS_KEY

  • AWS_REGION

  • AWS_ENDPOINT_URL_S3

License

Copyright (c) 2021 Wojtek Mach

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.