fix(server): log thrown errors

[iainsproat]

Description & motivation

The default error handler for express was not logging thrown errors. Requests which incurred internal errors had their responses logged as 500 errors without any corresponding error message or stacktrace. This made investigating errors difficult.

This PR amends the default error handler to add the error it is handling to the request context.
The request context is then used by the pino http logger and any included error is logged.

Changes:

• request.context.err is populated if express server encounters an error
• pino http logger includes request.context.err in the logged properties.

To-do before merge:

Screenshots:

Validation of changes:

Checklist:

• My pull request follows the guidelines in the Contributing guide?
• My pull request does not duplicate any other open Pull Requests for the same update/change?
• My commits are related to the pull request and do not amend unrelated code or documentation.
• My code follows a similar style to existing code.
• I have added appropriate tests.
• I have updated or added relevant documentation.

References