ConsulConfigProvider

Installation

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

def deps do
  [
    {:consul_config_provider, "~> 0.2"},
    {:finch, "~> 0.12"}, # default implementation for http client
  ]
end

• Only add in finch if you want to use the default http behaviour and not define your own client

The docs can be found at https://hexdocs.pm/consul_config_provider.

Sample Usage

• In mix.exs

releases: [
  release_name: [
    include_executables_for: [:unix],
    applications: [
      runtime_tools: :permanent,
      app_name_here: :permanent
    ],
    config_providers: [
      {ConsulConfigProvider,
       %{prefix: "services/app_namespace_in_consul/v1", app_name: :app_name_here}}
    ]
  ]
],

Transformer

• You can also implement an optional transformer behaviour to change the form of your configs
• This is helpful for interop with erlang modules that might have different opinions about things

defmodule Example.Config do
  @behaviour ConsulConfigProvider.Transformer

  @impl true
  def transform({:erlkaf, [clients: [producer: [client_options: client_options]]]}) do
    default_client_options =
      Application.get_env(:erlkaf, :clients, [])
      |> Keyword.get(:producer, [])
      |> Keyword.get(:client_options, [])

    {:erlkaf,
     [
       clients: [
         producer: [
           type: :producer,
           client_options: Keyword.merge(default_client_options, client_options)
         ]
       ]
     ]}
  end

  @impl true
  def transform(config), do: config
end

Then in your configs:

config :consul_config_provider, transformer_module: Example.Config

Information

• This provider assumes the config name has a file extension which is either .json, .yml, or .yaml no other extensions are supported although PRs would be welcomed. If you do not follow this naming convention the provider will not work and throw.
• In the above the prefix is used for the keys path and can also be set with CONSUL_PREFIX (provide an empty string to the prefix if you wish to just use the env var)
• The CONSUL_HOST env var is used for the host to talk to consul and defaults to localhost
• The CONSUL_PORT env var is used for the port to talk to consul and defaults to 8500
• The http_module is dynamic and you can specify your own if you choose to do so. Just implement the HTTP behaviour and make your implementation return an {:ok, json_body_binary_string} as per the finch example which will be the fallback. You might have to deal with coercing the input keyword list for the finch arguments to support the client you are using, as well. You also need to set config :consul_config_provider, :http_module, Client.YourClient pointing to your client in your configs.
• Dependency-related configs are namespaced with their own application name while other configs use the input app_name for their namespace

Release

• Increment mix.exs project version
• Update CHANGELOG.md
• Create a release in the github ui
• Github actions will create a hex release and upload it