100% agree that it’s about dependence on other teams. That said, I’d much rather that we were communicating across a well defined api boundary, rather than a graphql api. You could, of course, very easily do this with an api layer in the middle.
Nobody seems to get the idea of building software out of pieces with well defined APIs any more </rant>. I would say it's not possible to build large software without adhering to this principle but I seem to be proven wrong. You can build large poor quality software and just throw more people at it.
The other part about team dependence is very true but it also shows a lack of knowledge/thinking/care by whoever formed the teams. It seemed for a while Amazon had things right both in terms of boundaries of teams and in terms of forcing people to use APIs- not sure what they do these days.
The biggest issue with GRPC is that it is only suitable for stateful languages (iow, languages that can hold values and share them between requests). GRPC is basically worthless for stateless languages and unusable. These stateless languages also don’t work well for websockets either, so it is what it is.
Until they solve the stateful part, I’m not using it or recommending it to be used anywhere. Bandwidth is cheap, type safety is overrated, and compute is expensive.
It's the narrowest abstraction fitting those use cases. A database by its nature is a generic component. So sure, the piece of your software that's "SQL database" has a SQL interface, pretty quickly you'd want some abstractions on top of that around the different uses of that database.
The problem is when genericity diffuses its way into a large system it becomes impossible to maintain. How do you refactor a code base when everything everywhere is just SQL queries. If you want to change the schema how do you know you're not breaking anything? The short answer is you don't and so the software becomes incredibly brittle. The common workaround is testing but you can never test everything and now your tests also become coupled to everything else making things even more difficult to change.
The database in your example, while being generic is already an abstraction of sorts. Now if you're building lessay gmail the external users should see "create email", "get all emails", vs. issuing SQL queries to the database. That makes it easier to change the two pieces (client and server in this simplified example).
