Waffle Storage Google (forked from waffle_gcs)

Google Cloud Storage for Waffle, suppirting Goth 1.3+ and JSON credentials for Service Accounts.

What's Waffle?

Waffle (formerly Arc) is a file uploading library for Elixir. It's main goal is to provide "plug and play" file uploading and retrieval functionality for any storage provider (e.g. AWS S3, Google Cloud Storage, etc).

What's Waffle Storage Google?

Waffle Storage Google provides an integration between Waffle and Google Cloud Storage. It is (in my opinion) a fork of waffle_gcs. If you want to easily upload and retrieve files using Google Cloud Storage as your provider, and you also use Waffle, then this library is for you.

Installation

Add it to your mix dependencies:

defp deps do
  [
    ...,
    {:waffle_storage_google, "~> 0.0.2"}
  ]
end

Configuration

All configuration values are stored under the :waffle adn :waffle_storage_google

config :waffle,
  storage: Waffle.Storage.Google,
  bucket: "gcs-bucket",
  storage_dir: "uploads/waffle"

config :waffle_storage_google,
  credentials: System.get_env("GCP_CREDENTIALS") |> Jason.decode!()

Note: a valid bucket name is a required config. This can either be a hard-coded string (e.g. "gcs-bucket") or a system env tuple (e.g. {:system, "WAFFLE_BUCKET"}). You can also override this in your definition module (e.g. def bucket(), do: "my-bucket").

Authentication is done through a custom Goth instance initialized at startup from the service account credentials, decoded and stored in configuration (:waffle_storage_google -> :credentials).

URL Signing

If your bucket/object permissions do not allow for public access, you will need to use signed URLs to give people access to the uploaded files. This is done by either passing signed: true to Waffle.Storage.Google.url/4 or by setting it in the configs (config :waffle, signed: true). The default expiration time is one hour but can be changed by setting the :expires_in config/option value. The value is the number of seconds the URL should remain valid for after generation.

GCS object headers

You can specify custom object headers by defining gcs_object_headers/2 in your definition which returns keyword list or map. E.g.

def gcs_object_headers(_version, {_file, _scope}) do
  [contentType: "image/jpeg"]
end

The list of all the supported attributes can be found here: https://hexdocs.pm/google_api_storage/GoogleApi.Storage.V1.Model.Object.html.

Roadmap

Currently this is just a fork fixed to use Goth v4 but the plan is to:

support service accounts / metadata
switch URL signing algorithm to V4 by default (service accounts)
more flexible configuration, to allow reusing application's own Goth instance
configuration for requested scopes

hubertlepicki / waffle_storage_google