# DopplerConfigProvider

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[Doppler](https://doppler.com) ConfigProvider for [Elixir](https://elixir-lang.org/) projects.

## Installation

The package can be installed by adding `:doppler_config_provider` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:doppler_config_provider, "~> 0.4.2"},
    # Mojito is optional, but it is the default if you don't specify `:http_module` in options.
    {:mojito, "~> 0.7.10"},
  ]
end
```

## Usage

 1. Generate a [service token](https://docs.doppler.com/docs/enclave-service-tokens).
 2. Add necessary config.
 3. Add the config provider to `release` config in `mix.exs`.

### Options

 * `:service_token` (required) - The Doppler service token.
 * `:http_module` (optional) - The HTTP client module. Defaults to `{Mojito, :mojito}`. Should implement `DopplerConfigProvider.HTTPClient` behaviour.
 * `:json_module` (optional) - The JSON decoding module. Defaults to `{Jason, :jason}` or `{Poison, :poison}`. Should implement `DopplerConfigProvider.JSONDecoder` behaviour.
 * `:mappings` (required) - A map specifying how to translate the Doppler config to application config.

The `:http_module` and `:json_module` options can take either a module (e.g. `MyApp.Foobar`) or a tuple with the module
and the apps that need to be started for the module to work properly (e.g. `{MyApp.Foobar, :mojito}` or `{MyApp.Foobar, [:tesla, :hackney]}`).

### Config example:

```elixir
config :doppler_config_provider,
  service_token: System.fetch_env!("DOPPLER_TOKEN"),
  mappings: %{
    "DATABASE_URL" => [:my_app, MyApp.Repo, :url],
    "SECRET_KEY_BASE" => [:my_app, MyAppWeb.Endpoint, :secret_key_base],
    "STRIPE_SECRET_KEY" => [:stripity_stripe, :api_key],
  }
```

### `mix.exs` example:

```elixir
releases: [
  my_app: [
    # ...
    config_providers: [
      {DopplerConfigProvider, http_module: {MyDopplerHTTPClient, [:tesla, :hackney]}}
    ]
  ]
],
```

Notes:

 * The options provided to the config provider in `releases` are merged with
the config provided in your config files. The options passed in `mix.exs` take precedence.

## License

Copyright 2021 Ryan Winchester

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this project 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.