### Description
This PR removes `ServerConfigCtx` and `HasServerConfigCtx`. Instead, it favours different approaches:
- when the code was only using one field, it passes that field explicitly (usually `SQLGenCtx` or `CheckFeatureFlag`)
- when the code was using several fields, but in only one function, it inlines
- for the cache build, it introduces `CacheStaticConfig` and `CacheDynamicConfig`, which are subsets of `AppEnv` and `AppContext` respectively
The main goal of this is to help with the modularization of the engine: as `ServerConfigCtx` had fields whose types were imported from several unrelated parts of the engine, using it tied together parts of the engine that should not be aware of one another (such as tying together `Hasura.LogicalModel` and `Hasura.GraphQL.Schema`).
The bulk of this PR is a change to the cache build, as a follow up to #8509: instead of giving the entire `ServerConfigCtx` as a incremental rule argument, we only give the new `CacheDynamicConfig` struct, which has fewer fields. The other required fields, that were coming from the `AppEnv`, are now given via the `HasCacheStaticConfig` constraint, which is a "subset" of `HasAppEnv`.
(Some further work could include moving `StringifyNumbers` out of `GraphQL.Schema.Options`, given how it is used all across the codebase, including in `RQL.DML`.)
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8513
GitOrigin-RevId: 818cbcd71494e3cd946b06adbb02ca328a8a298e
- Remove `MonadMetadataStorageQueryAPI` which was only implemented by a default implementation
- Introduce `TransT` which can be used to easily derive `lift`ing implementations for `MonadBlaBlaBla` classes
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8579
GitOrigin-RevId: 4f804fda7e2de5c9d75ee4df269f500ebd46b8c9
Also add a `default` implementation for `MonadQueryTags`.
This avoids a bunch of imports on `Hasura.GraphQL.Execute.Backend` which is a big module with lots of (transitive) dependencies.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8571
GitOrigin-RevId: 8ecca452721b77953e6d088c79d8d6f003f2996f
## Description
This PR is a incremental step towards achieving the goal of #8344. It is a less ambitious version of #8484.
This PR removes all references to `HasServerConfigCtx` from the cache build and removes `ServerConfigCtx` from `CacheBuildParams`, making `ServerConfigCtx` an argument being passed around manually instead. This has several benefits: by making it an arrow argument, we now properly integrate the fields that change over time in the dependency framework, as they should be, and we can clean up some of the top-level app code.
## Implementation
In practice, this PR introduces a `HasServerConfigCtx` instance for `CacheRWT`, the monad we use to build the cache, so we can retrieve the `ServerConfigCtx` in the implementation of `CacheRWM`. This contributes to reducing the amount of `HasServerConfigCtx` in the code: we can remove `SchemaUpdateT` altogether, and we can remove the `HasServerConfigCtx` instance of `Handler`. This makes `HasServerConfigCtx` almost **an implementation detail of the Metadata API**.
This first step is enough to achieve the goal of #8344: we can now build the schema cache in the app monad, since we no longer rely on `HasServerConfigCtx` to build it.
## Drawbacks
This PR does not attempt to remove the use of `ServerConfigCtx` itself in the schema cache build: doing so would make this PR much much bigger. Ideally, to avoid having all the static fields given as arrow-ish arguments to the cache, we could depend on `HasAppEnv` in the cache build, and use `AppContext` as an arrow argument. But making the cache build depend on the full `AppEnv` and `AppContext` creates a lot of circular imports; and since removing `ServerConfigCtx` itself isn't required to achieve #8344, this PR keeps it wholesale and defers cleaning it to a future PR.
A negative consequence of this is that we need an `Eq` instance on `ServerConfigCtx`, and that instance is inelegant.
## Future work
There are several further steps we can take in parallel after this is merged. First, again, we can make a new version of #8344, removing `CacheBuild`, FINALLY. As for `ServerConfigCtx`, we can split it / rename it to make ad-hoc structures. If it turns out that `ServerConfigCtx` is only ever used for the schema cache build, we could split it between `CacheBuildEnv` and `CacheBuildContext`, which will be subsets of `AppEnv` and `AppContext`, avoiding import loops.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8509
GitOrigin-RevId: 01b37cc3fd3490d6b117701e22fc4ac88b62b6b5
- Derive a few `instance`s
- Delete some dead code (methods and types)
- Delete some `INLINE` pragmas that are unlikely to have a big effect
- Monomorphize Postgres `LISTEN` code to avoid effect juggling
- Generalize some methods in `pg-client` so that others can be simplified
- Handle errors differently for `TxET` to deduplicate code
- Use `hoist` instead of specialized combinators such as `mapActionT`
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8130
GitOrigin-RevId: bc1e908b6c0869f440a214a76744e92d40fea1e6
This PR is on top of #7789.
### Description
This PR entirely rewrites the API of the Tracing library, to make `interpTraceT` a thing of the past. Before this change, we ran traces by sticking a `TraceT` on top of whatever we were doing. This had several major drawbacks:
- we were carrying a bunch of `TraceT` across the codebase, and the entire codebase had to know about it
- we needed to carry a second class constraint around (`HasReporterM`) to be able to run all of those traces
- we kept having to do stack rewriting with `interpTraceT`, which went from inconvenient to horrible
- we had to declare several behavioral instances on `TraceT m`
This PR rewrite all of `Tracing` using a more conventional model: there is ONE `TraceT` at the bottom of the stack, and there is an associated class constraint `MonadTrace`: any part of the code that happens to satisfy `MonadTrace` is able to create new traces. We NEVER have to do stack rewriting, `interpTraceT` is gone, and `TraceT` and `Reporter` become implementation details that 99% of the code is blissfully unaware of: code that needs to do tracing only needs to declare that the monad in which it operates implements `MonadTrace`.
In doing so, this PR revealed **several bugs in the codebase**: places where we were expecting to trace something, but due to the default instance of `HasReporterM IO` we would actually not do anything. This PR also splits the code of `Tracing` in more byte-sized modules, with the goal of potentially moving to `server/lib` down the line.
### Remaining work
This PR is a draft; what's left to do is:
- [x] make Pro compile; i haven't updated `HasuraPro/Main` yet
- [x] document Tracing by writing a note that explains how to use the library, and the meaning of "reporter", "trace" and "span", as well as the pitfalls
- [x] discuss some of the trade-offs in the implementation, which is why i'm opening this PR already despite it not fully building yet
- [x] it depends on #7789 being merged first
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/7791
GitOrigin-RevId: cadd32d039134c93ddbf364599a2f4dd988adea8
## Description
### I want to speak to the `Manager`
Oh boy. This PR is both fairly straightforward and overreaching, so let's break it down.
For most network access, we need a [`HTTP.Manager`](https://hackage.haskell.org/package/http-client-0.1.0.0/docs/Network-HTTP-Client-Manager.html). It is created only once, at the top level, when starting the engine, and is then threaded through the application to wherever we need to make a network call. As of main, the way we do this is not standardized: most of the GraphQL execution code passes it "manually" as a function argument throughout the code. We also have a custom monad constraint, `HasHttpManagerM`, that describes a monad's ability to provide a manager. And, finally, several parts of the code store the manager in some kind of argument structure, such as `RunT`'s `RunCtx`.
This PR's first goal is to harmonize all of this: we always create the manager at the root, and we already have it when we do our very first `runReaderT`. Wouldn't it make sense for the rest of the code to not manually pass it anywhere, to not store it anywhere, but to always rely on the current monad providing it? This is, in short, what this PR does: it implements a constraint on the base monads, so that they provide the manager, and removes most explicit passing from the code.
### First come, first served
One way this PR goes a tiny bit further than "just" doing the aforementioned harmonization is that it starts the process of implementing the "Services oriented architecture" roughly outlined in this [draft document](https://docs.google.com/document/d/1FAigqrST0juU1WcT4HIxJxe1iEBwTuBZodTaeUvsKqQ/edit?usp=sharing). Instead of using the existing `HasHTTPManagerM`, this PR revamps it into the `ProvidesNetwork` service.
The idea is, again, that we should make all "external" dependencies of the engine, all things that the core of the engine doesn't care about, a "service". This allows us to define clear APIs for features, to choose different implementations based on which version of the engine we're running, harmonizes our many scattered monadic constraints... Which is why this service is called "Network": we can refine it, moving forward, to be the constraint that defines how all network communication is to operate, instead of relying on disparate classes constraint or hardcoded decisions. A comment in the code clarifies this intent.
### Side-effects? In my Haskell?
This PR also unavoidably touches some other aspects of the codebase. One such example: it introduces `Hasura.App.AppContext`, named after `HasuraPro.Context.AppContext`: a name for the reader structure at the base level. It also transforms `Handler` from a type alias to a newtype, as `Handler` is where we actually enforce HTTP limits; but without `Handler` being a distinct type, any code path could simply do a `runExceptT $ runReader` and forget to enforce them.
(As a rule of thumb, i am starting to consider any straggling `runReaderT` or `runExceptT` as a code smell: we should not stack / unstack monads haphazardly, and every layer should be an opaque `newtype` with a corresponding run function.)
## Further work
In several places, i have left TODOs when i have encountered things that suggest that we should do further unrelated cleanups. I'll write down the follow-up steps, either in the aforementioned document or on slack. But, in short, at a glance, in approximate order, we could:
- delete `ExecutionCtx` as it is only a subset of `ServerCtx`, and remove one more `runReaderT` call
- delete `ServerConfigCtx` as it is only a subset of `ServerCtx`, and remove it from `RunCtx`
- remove `ServerCtx` from `HandlerCtx`, and make it part of `AppContext`, or even make it the `AppContext` altogether (since, at least for the OSS version, `AppContext` is there again only a subset)
- remove `CacheBuildParams` and `CacheBuild` altogether, as they're just a distinct stack that is a `ReaderT` on top of `IO` that contains, you guessed it, the same thing as `ServerCtx`
- move `RunT` out of `RQL.Types` and rename it, since after the previous cleanups **it only contains `UserInfo`**; it could be bundled with the authentication service, made a small implementation detail in `Hasura.Server.Auth`
- rename `PGMetadaStorageT` to something a bit more accurate, such as `App`, and enforce its IO base
This would significantly simply our complex stack. From there, or in parallel, we can start moving existing dependencies as Services. For the purpose of supporting read replicas entitlement, we could move `MonadResolveSource` to a `SourceResolver` service, as attempted in #7653, and transform `UserAuthenticationM` into a `Authentication` service.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/7736
GitOrigin-RevId: 68cce710eb9e7d752bda1ba0c49541d24df8209f
## Description
This PR removes `MetadataStorageT`, and cleans up all top-level error handling. In short: this PR changes `MonadMetadataStorage` to explicitly return a bunch of `Either QErr a`, instead of relying on the stack providing a `MonadError QErr`. Since we implement that class on the base monad *below any ExceptT*, this removes a lot of very complicated instances that make assumptions about the shape of the stack.
On the back of this, we can remove several layers of ExceptT from the core of the code, including the one in `RunT`, which allows us to remove several instances of `liftEitherM . runExceptT`.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/7689
GitOrigin-RevId: 97d600154d690f58c0b93fb4cc2d30fd383fd8b8
