# Rkv
[](https://github.com/nmbrone/rkv/actions/workflows/ci.yml)
A simple ETS-based key-value storage with the ability to watch changes.
## Installation
The package can be installed by adding `rkv` to your list of dependencies in `mix.exs`:
<!-- x-release-please-start-version -->
```elixir
def deps do
[
{:rkv, "~> 0.1.0"}
]
end
```
<!-- x-release-please-end -->
## Usage
You can start `Rkv` directly or as part of a supervision tree.
### Starting the bucket
```elixir
# Start the process
{:ok, _pid} = Rkv.start_link(bucket: :my_bucket)
```
### Basic Operations
```elixir
# Put a value
:ok = Rkv.put(:my_bucket, "key", "value")
# Get a value
"value" = Rkv.get(:my_bucket, "key")
# Get a missing value
nil = Rkv.get(:my_bucket, "missing")
# Get with default
"default" = Rkv.get(:my_bucket, "missing", "default")
# Delete a value
:ok = Rkv.delete(:my_bucket, "key")
```
### Supervision
Add `Rkv` to your supervision tree:
```elixir
defmodule MyApp.Application do
use Application
def start(_type, _args) do
children = [
{Rkv, bucket: :my_app_cache}
]
opts = [strategy: :one_for_one, name: MyApp.Supervisor]
Supervisor.start_link(children, opts)
end
end
```
### Watching Changes
You can subscribe to changes on a specific key or the entire bucket.
```elixir
# Watch a specific key
Rkv.watch_key(:my_bucket, "config")
Rkv.put(:my_bucket, "config", %{debug: true})
receive do
{:updated, :my_bucket, "config"} -> IO.puts "Config updated!"
end
# Watch all keys
Rkv.watch_all(:my_bucket)
Rkv.put(:my_bucket, "other_key", 123)
receive do
{:updated, :my_bucket, "other_key"} -> IO.puts "Something changed!"
end
```
