#  Kungfuig [](https://kantox.com/)  
## Intro
Live config supporting many different backends.
**Kungfuig** (_pronounced:_ [ˌkʌŋˈfig]) provides an easy way to plug
live configuration into everything.
It provides backends for `env` and `system` and supports custom backends.
## Installation
```elixir
def deps do
[
{:kungfuig, "~> 0.1"}
]
end
```
## Using
**Kungfuig** is the easy way to read the external configuration from sources that are not controlled by the application using it, such as _Redis_, or _Database_.
Here is the example of backend implementation for the config read from external _MySQL_.
```elixir
defmodule MyApp.Kungfuig.MySQL do
@moduledoc false
use Kungfuig.Backend
@impl Kungfuig.Backend
def get(_meta) do
with {:ok, host} <- System.fetch_env("MYSQL_HOST"),
{:ok, db} <- System.fetch_env("MYSQL_DB"),
{:ok, user} <- System.fetch_env("MYSQL_USER"),
{:ok, pass} <- System.fetch_env("MYSQL_PASS"),
{:ok, pid} when is_pid(pid) <-
MyXQL.start_link(hostname: host, database: db, username: user, password: pass),
result <- MyXQL.query!(pid, "SELECT * FROM some_table") do
GenServer.stop(pid)
result =
result.rows
|> Flow.from_enumerable()
|> Flow.map(fn [_, field1, field2, _, _] -> {field1, field2} end)
|> Flow.partition(key: &elem(&1, 0))
|> Flow.reduce(fn -> %{} end, fn {field1, field2}, acc ->
Map.update(
acc,
String.to_existing_atom(field1),
[field2],
&[field2 | &1]
)
end)
Logger.info("Loaded #{Enum.count(result)} values from " <> host)
{:ok, result}
else
:error ->
Logger.warn("Skipped reconfig, one of MYSQL_{HOST,DB,USER,PASS} is missing")
:ok
error ->
Logger.error("Reconfiguring failed. Error: " <> inspect(error))
{:error, error}
end
end
end
```
## Testing
Simply implement a stub returning an expected config and you are all set.
```elixir
defmodule MyApp.Kungfuig.Stub do
@moduledoc false
use Kungfuig.Backend
@impl Kungfuig.Backend
def get(_meta), do: %{foo: :bar, baz: [42]}
end
```
## Changelog
- **`1.0.0`** — modern Elixir v1.16
- **`0.4.4`** — fix a bug with hardcoded names (`Supervisor` and `Blender`)
- **`0.4.2`** — allow `imminent: true` option to `Kungfuig.Backend`
- **`0.4.0`** — allow named `Kungfuig.Supervisor` (thanks @vbroskas)
- **`0.3.0`** — allow validation through `NimbleOptions` (per backend and global)
- **`0.2.0`** — scaffold for backends + several callbacks (and the automatic one for `Blender`)
## [Documentation](https://hexdocs.pm/kungfuig)
