nobt-io / api Goto Github PK

Currently, we return bills and debts to the frontend. However, in addition to the debts, the frontend also shows the balances of each participant. This information is not present in the API response and hence, the frontend needs to calculate it by itself.

This is:

1. error prone: the frontend is written in JS and has barely and tests
2. inconsistent in terms of responsibilities: the frontend should focus on design and UX, not on doing math

In addition, we recently introduced property-based tests into the backend to have more thorough tests and better guarantees that our optimization algorithms actually behave correctly.
For these tests, we already calculate the balances of each participant because no matter how we optimize the debts, the balances always need to stay the same: they are the perfect metric to check on whether an optimization algorithm is correct.
However, at the moment, all this logic is part of the test suite and not the production code.
If we return balances in the API we can:

1. Move this code to the production code and thereby support it properly (this will clean up the tests quite a bit)
2. Remove some math from the frontend

Currently, there is no way too request configuration options from the API. It would be good to have an endpoint that returns stuff like:

• what is the current optimizer for new nobts
• whether the API is using an in-memory db or connected to a real database

Note that this is different from an actual healthcheck endpoint that would return information about the connected database. A healthcheck endpoint is out-of-scope of this issue.

Initially, we thought "expenses" and "transactions" are good terms. But they are not :D

We should add new endpoints to the API that use our newly adopted terminology so that the frontend doesn't have to do that much mapping in its presentation code.

Terminology to be changed:

• expenses -> bills
• transactions -> debts

https://medium.com/@flbenz/create-postman-collections-out-of-tests-7ee05c8c1883

Currently, we have self-made classes for handling amount and currencies. We should replace that with JodaMoney (http://www.joda.org/joda-money/) or JavaMoney (https://github.com/JavaMoney/jsr354-ri)

Currently, the documentation states the following about the currencyInformation object:

An object defining the conversion information to the currency of the associated nobt. If this object is present, the amounts of this expense are to be interpreted in the given currency. If this object is not present, it is assumed that the currency of this expense is equal to the currency of the nobt, hence the conversion rate is 1.

This is not correct.
The amounts listed in the shares are always in the currency of the nobt. The conversion information object represents the rate and the original currency. Clients can utilize this object to store information about the amounts that were entered by the user:

• the original currency
• the rate the client used to convert the entered amounts into the nobt currency

The API is started from a different working dir than locally (outside bin).
Therefore the call to staticFileLocation does not work.

• Only deploy on tags
• Store artifact in github release
• Link to latest release from README

Useful link: travis-ci/travis-ci#6132

The timestamps for createdOn should actually be Instant and not ZonedDateTime.

From the documentation of Instant:

This class models a single instantaneous point on the time-line. This might be used to record event time-stamps in the application.

The API should allow to delete bills from a nobt, however, they should not be actually deleted from the DB but instead "marked" deleted with a flag or something like that. During the debt-calculation, these bills have to be filtered out.

Also, the API should advertise to the client that bills can be deleted. I would suggest adding a link to each bill's resource payload like this:

{
	"id": 3,
	"name": "Beer",
        // other properties
	"_links": {
		"delete": {
			"href": "..."
		}
	}
}

For now, this link is always present. Later on, we can change whether or not bills can be deleted by excluding the links under certain conditions (e.g. time-limit etc)

Starting with nobt-io/frontend#301, we use netlify and have deploy previews for each branch.

It would be good to have a dev version of the API sitting at dev-api.nobt.io which only uses an in-memory database.

This API could then be used to test deploy previews without polluting the production database too much.

Currently, the client knows the endpoints for creating expenses and payments. We should add links to the response of a Nobt that points clients to these endpoints.

{
	"id": "g943hNß57gha",
	...
	"_links": {
		"create-expense": {
			"href": "..."
		},
		"create-payment": {
			"href": "..."
		}
	}
}

Implementation hints can be taken from the "delete" link of expenses. See #8.

We could expose metrics about our nobts in the database in prometheus format.

This is a bit of a hack but it gives us some reasonably easy analytics without setting anything else up.

The newly added property-based test for the optimizer seems to fail rarely.

Should investigate that :)

Problem

This incident is a combination of several problems, with one of them being a trailing space in the name "Blair".

Goal

Avoid errors as soon as possible.

Recommendation

Sanitize the input from the frontend better, especially all "name" fields. We should remove any whitespace character from the front and back of all names.

There seems to be an issue related to persistence of deleted bills.

https://sentry.io/share/issue/f57b492f905b475f9cb7526431b3fb91/

http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.managing.elb.html#using-features.managing.elb.healthchecks