# PhxExRay
> _The first x is silent_
[](https://hex.pm/packages/phx_ex_ray)
Wrapper around [ex_ray](https://github.com/derailed/ex_ray) for OpenTrace in Elixir Phoenix. Initial implementation based on the [ex_ray_tracers](https://github.com/derailed/ex_ray_tracers) example.
## Installation
If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `phx_ex_ray` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:phx_ex_ray, "~> 0.1.0"}
]
end
```
Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
be found at [https://hexdocs.pm/phx_ex_ray](https://hexdocs.pm/phx_ex_ray).
## Usage
Configure [otter](https://github.com/Bluehouse-Technology/otter):
```elixir
config :otter,
zipkin_collector_uri: 'http://127.0.0.1:9411/api/v1/spans',
zipkin_tag_host_service: "MyApp"
```
> `zipkin_collector_uri` must be a char list
Configure application:
```elixir
# application.ex
...
ExRay.Store.create()
...
```
### Plug Usage
```elixir
# lib/my_app/endpoint.ex
...
plug PhxExRay.Tracing.Plug
...
```
### Controller Usage
Cross controller set up:
```elixir
# lib/my_app/my_app_web.ex
def controller do
quote do
...
import PhxExRay.Span
...
end
end
```
Then in a specific controller:
```elixir
use PhxExRay.Span, :controller
@trace kind: :action
def index(conn, _params) do
...
end
```
### Database Context Usage
In a context, or any file where you use `alias MyApp.Repo`:
```elixir
use PhxExRay.Span, {:context, MyApp.Repo}
...
@trace query: :list_all_users, kind: :all, queryable: User
def list_users() do
Repo.all(User)
end
# or
@trace query: :get_user_or_explode, sql: "SELECT * FROM users WHERE (id = X)"
def get_user!(id), do: Repo.get!(User, id)
```
### Http Client Usage
[ex_ray](https://github.com/derailed/ex_ray#installation) provides integration for http client tracing. Additional config required to specific which http client you want to use:
```elixir
config :otter,
...
http_client: (:ibrowse|:httpc|:hackney)
```
