PPD missing 404 templates

[der]

We see repeated ppd errors:

[Missing template application/render_404 with {:locale=>[:en], :formats=>[:css],](https://github.com/epimorphics/master-ansible-deployment/blob/main/epimorphics/deployment/roles/metrics/templates/prometheus-rules/Readme.md#applicationinternalerror)

404's are to be expected and should not result in alert messages.

[jonrandahl]

@der & @andrew-pickin-epi could anyone clarify why the path from the log above is referencing the https://github.com/epimorphics/master-ansible-deployment/blob/main/epimorphics/deployment/roles/metrics/templates/prometheus-rules/Readme.md file? 🤔

[der]

That's a cut/paste of the markdown format sent to slack. That URI is a link to the definition of what an "applicationInternalError" is.

The full message content on slack is:

Missing template application/render_404 with {:locale=>[:en], :formats=>[:css], :variants=>[], :handlers=>[:raw, :erb, :html, :builder, :ruby, :jbuilder, :haml]}. Searched in:
 * "/usr/src/app/app/views"
 * "/usr/local/bundle/gems/govuk_template-0.18.3/app/views"
 * "/usr/local/bundle/gems/lr_common_styles-1.9.3/app/views"

[der]

Don't know if the :formats=>[:css] is significant here. That the issue is a missing CSS file and the 404 response for those is handled differently?