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# New Relic's Elixir Agent
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[](https://hex.pm/packages/new_relic_agent)
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The Open-Source Elixir Agent allows you to monitor your `Elixir` applications with New Relic. It helps you track transactions, distributed traces and other parts of your application's behavior and provides an overview of underlying [BEAM activity](https://github.com/newrelic/elixir_agent/wiki/BEAM-stats-page).
[View the Documentation](https://hexdocs.pm/new_relic_agent)
### Support Statement
New Relic has open-sourced this project to enable monitoring of `Elixir` applications. This project is provided AS-IS WITHOUT WARRANTY OR SUPPORT, although you can report issues and contribute to the project here on GitHub.
### Contributing
We'd love to get your contributions to improve the elixir agent! Keep in mind when you submit your pull request, you'll need to sign the CLA via the click-through using CLA-Assistant. If you'd like to execute our corporate CLA, or if you have any questions, please drop us an email at [[email protected]](mailto:[email protected]).
## Installation
Install the [Hex package](https://hex.pm/packages/new_relic_agent)
Requirements:
* Erlang/OTP 21
* Elixir 1.8
```elixir
defp deps do
[
{:new_relic_agent, "~> 1.0"}
]
end
```
## Configuration
You need to set a few required configuration keys so we can authenticate properly.
#### Via Application config
```elixir
config :new_relic_agent,
app_name: "My App",
license_key: "license_key"
```
#### Via Environment variables
You can also configure these attributes via `ENV` vars, which helps keep secrets out of source code.
* `NEW_RELIC_APP_NAME`
* `NEW_RELIC_LICENSE_KEY`
## Instrumentation
Out of the box, we will report Error Traces & some general BEAM VM stats. For further visibility, you'll need to add some basic instrumentation.
#### Telemetry
Some Elixir packages are auto-instrumented via [`telemetry`](https://github.com/beam-telemetry/telemetry)
* [`Ecto`](https://github.com/elixir-ecto/ecto): See [NewRelic.Telemetry.Ecto](https://github.com/newrelic/elixir_agent/blob/master/lib/new_relic/telemetry/ecto.ex) for details.
#### Plug
Plug instrumentation is built into the agent.
* `NewRelic.Transaction` enables rich Transaction Monitoring for a `Plug` pipeline. It's a macro that injects a few plugs and an error handler. Install it by adding `use NewRelic.Transaction` to your Plug module.
```elixir
defmodule MyPlug do
use Plug.Router
use NewRelic.Transaction
# ...
end
```
#### Function Tracing
* `NewRelic.Tracer` enables detailed Function tracing. Annotate a function and it'll show up as a span in Transaction Traces / Distributed Traces, and we'll collect aggregate stats about it. Install it by adding `use NewRelic.Tracer` to any module, and annotating any function with `@trace` module attribute
```elixir
defmodule MyModule do
use NewRelic.Tracer
@trace :func
def func do
# Will report as `MyModule.func/0`
end
end
```
* `NewRelic.Tracer` also enables detailed External request tracing. A little more instrumentation is required to pass the trace context forward with Distributed Tracing.
```elixir
defmodule MyExternalService do
use NewRelic.Tracer
@trace {:request, category: :external}
def request(method, url, headers) do
NewRelic.set_span(:http, url: url, method: method, component: "HttpClient")
headers = headers NewRelic.distributed_trace_headers(:http)
HttpClient.request(method, url, headers)
end
end
```
#### Pre-Instrumented Modules
* `NewRelic.Instrumented.Mix.Task` To enable the Agent and record a Transaction during a `Mix.Task`, simply `use NewRelic.Instrumented.Mix.Task`. This will ensure the agent is properly started, record the Transaction, and shut down.
```elixir
defmodule Mix.Tasks.Example do
use Mix.Task
use NewRelic.Instrumented.Mix.Task
def run(args) do
# ...
end
end
```
* `NewRelic.Instrumented.HTTPoison` Automatically wraps HTTP calls in a span, and adds an outbound header to track the request as part of a Distributed Trace.
```elixir
alias NewRelic.Instrumented.HTTPoison
HTTPoison.get("http://www.example.com")
```
#### Other Transactions
You may start an "Other" Transaction for non-HTTP related work. This could used be while consuming messages from a broker, for example.
To start an other transaction:
```elixir
NewRelic.start_transaction(category, name)
```
And to stop the transaction within the same process:
```elixir
NewRelic.stop_transaction()
```
#### Adapters
There are a few adapters which leverage this agent to provide library / framework specific instrumentation. Note that these will eventually be replaced with `telemetry` based instrumentation.
* `Phoenix` https://github.com/binaryseed/new_relic_phoenix
* `Absinthe` https://github.com/binaryseed/new_relic_absinthe
