ConfigServer

Concept

Many applications need configuration that might change at runtime. ConfigServer can deliver configuration which is stored in a git repository.

The repository is cloned into the local file system and pulled from the origin at regular intervals.

Installation

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

def deps do
  [
    {:config_server, "~> 0.4.1"}
  ]
end

Configuration

If you are using http:

config :config_server,
  repo_url: "https://ghp_XXX@github.com/odo/config_server",
  repo_path: "/tmp/config_server_checkout",
  pull_interval_ms: 1000,
  state_change_fun: fn(old_config, new_config) -> IO.inspect({old_config, new_config}) end

If you are using ssh and want a specific branch to be used plus a custom parser:

config :config_server,
  repo_url: "git@github.com:odo/config_server",
  git_ssh_command: "ssh -i ~/.ssh/my_private_key", 
  repo_path: "/tmp/config_server_checkout",
  branch: "staging",
  pull_interval_ms: 1000,
  state_change_fun: fn(old_config, new_config) -> IO.inspect({old_config, new_config}) end,
  parsing_fun: {MyParser, :parse},
  start: false

repo_url

This can be

• A directory file:///path/to/repo/directory
• A HTTP URL like https://token@github.com/foo/bar
• SSH path like git@github.com:odo/config_server together with git_ssh_command (see above)

repo_path

A path where the checkout of your configuration repository lives.

state_change_fun

((any(), any()) -> :ok | :error | {:error, any()})

This can be skipped or can be defined as {module, function}. ConfigServer will pass in the old and new configuration as arguments. Initially, the old configuration will be nil. If state_change_fun returns :error or {:error, something} then that means that the configuration is faulty and ConfigServer rolls back to the previous configuration.

parsing_fun

((String.t()) -> {:ok, any()} | {:error, any()})

The default parser looks for Json files, parses them and puts them into one big map. If you like to do something else you can pass the :parsing_fun option to turn the checkout path of the repo into the configuration you need.

start

If set to false prevents the app from starting and you can start ConfigServer under your supervisor.

Usage

To retrieve the current configuration, call ConfigServer.config().

Format

The config repo is returned as a map with file names as keys and file content as values. Json files are parsed and the .json ending is filtered out. Files and directories starting with dots are ignored.