Try making puma metrics work by probing in puma workers

[albertchae]

Summary of the problem

Still having issues with puma metrics reporting in appsignal

Describe your changes

Follow instructions in https://docs.appsignal.com/ruby/integrations/puma.html#usage-with-preload_app

[sentry]

Bug: Incorrect AppSignal method names Appsignal::Probes.stop and Appsignal::Probes.start are used in Puma callbacks, leading to NoMethodError.
_{Severity: CRITICAL | Confidence: High}

🔍 Detailed Analysis

The code in config/puma.rb calls incorrect method names on the AppSignal gem: Appsignal::Probes.stop and Appsignal::Probes.start. When Puma executes these callbacks in non-development environments (where preload_app! is enabled), it will attempt to call methods that do not exist on the AppSignal gem. This will raise a NoMethodError or NameError. In the before_fork callback, the Puma master process will crash before it can fork workers. In the on_worker_boot callback, each worker process will crash before it can accept requests, causing the application to fail to start in production.

💡 Suggested Fix

Replace Appsignal::Probes.stop with Appsignal.stop_probes and Appsignal::Probes.start with Appsignal.start_probes in config/puma.rb.

🤖 Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent.
Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not
valid.

Location: config/puma.rb#L57-L64

Potential issue: The code in `config/puma.rb` calls incorrect method names on the
AppSignal gem: `Appsignal::Probes.stop` and `Appsignal::Probes.start`. When Puma
executes these callbacks in non-development environments (where `preload_app!` is
enabled), it will attempt to call methods that do not exist on the AppSignal gem. This
will raise a `NoMethodError` or `NameError`. In the `before_fork` callback, the Puma
master process will crash before it can fork workers. In the `on_worker_boot` callback,
each worker process will crash before it can accept requests, causing the application to
fail to start in production.

_{Did we get this right? 👍 / 👎 to inform future reviews.
Reference ID: 3466918}