Tracking user activity is very important in the context of an application. I mean the possibility of checking logs regarding actions performed in the system.
Sometimes, however, our application collects more logs than expected.
A great example is the redundant logging of endpoints responsible for the server status, such as /_health.
I want to share with you my way of reducing the number of such entries. In my case, each instance is polled for status every five seconds, which gives 12 queries per minute, 720 per hour, and over 17 000 new logs per day. For one instance only! Many applications often have several or more instances.
Health check
The easiest way to achieve the goal is to transfer the action from the router directly to the plug:
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# lib/my_web_app/router.ex
# get("/_health", StatusController, :health)
# lib/my_web_app/plugs/health_check.ex
defmodule MyWebApp.HealthCheck do
import Plug.Conn
@response "All good"
def init(opts), do: opts
def call(%Plug.Conn{request_path: "/_health"} = conn, _opts) do
conn
|> send_resp(200, @response)
|> halt()
end
def call(conn, _opts), do: conn
end
In my case, I used the /_health endpoint; however, you can change it.
It is very important to include halt(conn) in your code as this allows you to stop any further processing of the request within the existing pipeline.
It is enough to insert our health check at the beginning of our endpoint configuration. It is important that it is placed before the Logger settings:
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# lib/my_web_app/endpoint.ex
defmodule MyAppWeb.Endpoint do
use Phoenix.Endpoint, otp_app: :my_app_web
# Response for /_health path, without logs and tracking
plug(MyWebApp.HealthCheck)
...
end
Summary
This way, you can query the status of the application without creating a new entry in the logs.
Check for yourself by going to the <API_URL> _health page, where you should get information about the success, and at the same time, nothing new should be presented in the console or the log.
With this small change, you can reduce the number of created logs. It will allow you to focus on important actions instead of browsing additional entries regarding checking the application status.