Pretty error pages not rendering in dev after Phoenix upgrade

Harrygr · November 20, 2021, 10:04pm

I’ve just upgraded my version of Phoenix (and the Sentry client) which resulted in the following changes:

-  "certifi": {:hex, :certifi, "2.6.1", ...
+  "certifi": {:hex, :certifi, "2.8.0", ...

-  "hackney": {:hex, :hackney, "1.17.4", ...
+  "hackney": {:hex, :hackney, "1.18.0", ...

-  "phoenix": {:hex, :phoenix, "1.5.9", ...
+  "phoenix": {:hex, :phoenix, "1.5.13", ...

-  "plug": {:hex, :plug, "1.11.1", ...
+  "plug": {:hex, :plug, "1.12.1", ...

-  "plug_cowboy": {:hex, :plug_cowboy, "2.5.0", ...
+  "plug_cowboy": {:hex, :plug_cowboy, "2.5.2", ...

-  "poison": {:hex, :poison, "3.1.0", ...
+  "poison": {:hex, :poison, "4.0.1", ...

-  "sentry": {:hex, :sentry, "6.4.2", ...
+  "sentry": {:hex, :sentry, "8.0.0", ...

Everything seems to work OK, except when an exception is thrown in dev I no longer get the pretty exception page provided by phoenix. Instead I the response body is just Something went wrong:

HTTP/1.1 500 Internal Server Error

Something went wrong

Any idea why this has happened and how to resolve? I assume the pretty error page is still default behaviour for the dev environment.

axelson · November 20, 2021, 10:18pm

What error message do you have in the elixir console?

Also did you follow the sentry upgrade guide since you’re updating a major version?

gist.github.com

https://gist.github.com/mitchellhenke/dce120a5515565076b13962ee0be749b

upgrade.md

# Sentry 8.0

Sentry Elixir 8.0 is a major release containing significant changes, particularly around Elixir's major improvements to the core Logger module. Because of that, the required Elixir version will be Elixir 1.10. There are also a handful of steps to complete the upgrade below. A special thank you goes to José Valim for his help and contributions to this release.

A more detailed explanation of the changes is below, with instructions to upgrade, but the summary of changes is:

* Enhancements
  * Cache environment config in application config (#393)
  * Allow configuring LoggerBackend to send all messages, not just exceptions (e.g. `Logger.error("I am an error message")`)

This file has been truncated. show original

Harrygr · November 20, 2021, 10:34pm

What error message do you have in the elixir console?

I just manually raised an error in a controller handler. The error is correctly printed in the elixir console.

Also did you follow the sentry upgrade guide

I thought I had, but had neglected to remove Plug.ErrorHandler as described. It looks like removing it has allowed the pretty error printing to return.