Improve API error handling

[andyjac]

1. Dig into graphql errors types and what they mean/best practices around using them

• What error should we be using when a record isn't found (404 cases)?
• When should the generic ApolloError be used?
• In general, what are the best practices for error handling and structure in graphql applications?

2. Deduplicate error logic

At the moment we have string literals floating around in various places for error messages. We should:

1. Codify and unify the language we use for error messages (is is Shipment not found or Shipment does not exist?)
2. Encapsulate these error strings in some sort of structure/class that can be reused

[coderbyheart]

See

shipment-tracker/src/resolvers/input-validation/errorsToProblemDetails.ts

Lines 6 to 40 in 84ea3d6

	export type ProblemDetail = {
	/**
	* A URI reference [RFC3986] that identifies the problem type.
	* This specification encourages that, when dereferenced, it provide
	* human-readable documentation for the problem type
	* (e.g., using HTML [W3C.REC-html5-20141028]).
	* When this member is not present, its value is assumed to be "about:blank".
	*/
	type?: string
	/**
	* A short, human-readable summary of the problem type.
	* It SHOULD NOT change from occurrence to occurrence of the problem, except
	* for purposes of localization (e.g., using proactive content negotiation;
	* see [RFC7231], Section 3.4).
	*/
	title: string
	/**
	* The HTTP status code ([RFC7231], Section 6) generated by the origin
	* server for this occurrence of the problem.
	*/
	status?: number
	/**
	* A human-readable explanation specific to this occurrence of the problem.
	*/
	detail?: string
	/**
	* A URI reference that identifies the specific occurrence of the problem.
	* It may or may not yield further information if dereferenced.
	*/
	instance?: string
	}

for a way to express API errors.

IMO ApolloError schould not be used for internal error, instead EntityNotFound which then is wrapped into problem details.

In the end it depends on how the frontend would like to present errors.

[coderbyheart]

This has been added to the REST API: 93a304a