During the "generalization" of the code, we removed the [generated instances](9d63187803 (diff-7b8382ab20e441fa214586be491eb6f7ca904d8b20ed97894c16a339be45219aL72)) of `Eq` and `Hashable` in favour of manually written ones, because for a time we were struggling with `AnyBackend`.
In the process, we lost one constructor, `MOEndpoint`. It's unlikely to have ever been an issue, since duplicate endpoints are unlikely, but it is nonetheless wrong.
This PR simply goes back to default derived instances, now that we can, fixing the problem and making the code simpler.
---
However, after filing this PR, I realized **it broke rest endpoint tests**. Upon closer inspection, it turns out that while we had proper checks in place, because of this bug we were actually failing _differently_ during metadata checks. This PR actually improves error messages for invalid endpoint configurations?! 🙀
This is a tiny bit scary. ^^'
https://github.com/hasura/graphql-engine-mono/pull/1762
GitOrigin-RevId: c4897d1f3ae92d18c44c87d2f58258c66f716686
### Description
In our haste to generalize everything for MSSQL, we put every single "suspicious" type in Backend, including ones that weren't required. `Alias` is one of those: it's only used in a type alias, and is actually just an implementation detail of the translation layer. This PR removes it.
https://github.com/hasura/graphql-engine-mono/pull/1759
GitOrigin-RevId: fb348934ec65a51aae7f95d93c83c3bb704587b5
### Description
This PR removes all `fmapX` and `traverseX` functions from RQL.IR, favouring instead `Functor` and `Traversable` instances throughout the code. This was a relatively straightforward change, except for two small pain points: `AnnSelectG` and `AnnInsert`. Both were parametric over two types `a` and `v`, making it impossible to make them traversable functors... But it turns out that in every single use case, `a ~ f v`. By changing those types to take such an `f :: Type -> Type` as an argument instead of `a :: Type` makes it possible to make them functors.
The only small difference is for `AnnIns`, I had to introduce one `Identity` transformation for one of the `f` parameters. This is relatively straightforward.
### Notes
This PR fixes the most verbose BigQuery hint (`let` instead of `<- pure`).
https://github.com/hasura/graphql-engine-mono/pull/1668
GitOrigin-RevId: e632263a8c559aa04aeae10dcaec915b4a81ad1a
### Context
One of the ways we use the Backend type families is to use `Void` for all types for which a backend has no representation; this allows us to make some branches of our metadata and IR unrepresentable, making some functions total, where they would have to handle those unsupported cases otherwise.
However, one of the biggest features, functions, cannot be cut that way, due to one of the constraints on `FunctionName b`: the metadata generator requires it to have an `Arbitrary` instance, and `Arbitrary` does not have a recovery mechanism which would allow for a `Void` instance...
### Description
This PR solves this problem and removes the `Arbitrary` constraints in `Backend`. To do so, it introduces a new typeclass: `PartialArbitrary`, which is very similar to `Arbitrary`, except that it returns a `Maybe (Gen a)`, allowing for `Void` to have a well-formed instance. An `Arbitrary` instance for `Metadata` can easily be retrieved with `arbitrary = fromJust . partialArbitrary`.
Furthermore, `PartialArbitrary` has a generic implementation, inspired by the one in `generic-arbitrary`, which automatically prunes branches that return `Nothing`, allowing to automatically construct most types. Types that don't have a type parameter and therefore can't contain `Void` can easily get their `PartialArbitrary` instance from `Arbitrary` with `partialArbitrary = Just arbitrary`. This is what a default overlappable instance provides.
In conjunction with other cleanups in #1666, **this allows for Void function names**.
### Notes
While this solves the stated problem, there are other possible solutions we could explore, such as:
- switching from QuickCheck to a library that supports that kind of pruning natively
- removing the test altogether, and dropping all notion of Arbitrary from the code
There are also several things we could do with the Generator module:
- move it out of RQL.DDL.Metadata, to some place that makes more sense
- move ALL Arbitrary instances in the code to it, since nothing else uses Arbitrary
- or, to the contrary, move all those Arbitrary instances alongside their types, to avoid an orphan instance
https://github.com/hasura/graphql-engine-mono/pull/1667
GitOrigin-RevId: 88e304ea453840efb5c0d39294639b8b30eefb81
### Description
This PR fixes a major issue in the JSON instances of `AnyBackend`: they were not symmetrical! `FromJSON` always made the assumption that the value was an object, and that it contained a "kind" field if it happened to not be a Postgres value. `ToJSON` did NOT insert said field in the output, and did not enforce that the output was an object.
....however, it worked, because nowhere in the code did we yet rely on those being symmetrical. They are both used only once:
- `parseJSON` was used to decode a `Metadata` object, but the matching `toJSON` instance, which is heavily customized, does insert the "kind" field properly
- `toJSON` was only used on the `SchemaCache`, which has no corresponding `FromJSON` instance, since we only serialize it in debug endpoints
This PR makes no attempt at making the instances symmetrical. Instead, it implements simpler functions, and pushes the problem of identifying the proper backend (if any) to the call sites.
### Notes
Additionally, it cleans up some instances that were manually written where they could be auto-generated. In the process, this PR changes the semantics of `Show`, since the stock derived instance will include the constructor name, where before it was skipped. I think it is preferable.
https://github.com/hasura/graphql-engine-mono/pull/1672
GitOrigin-RevId: 0a1580a0e0f01c25b8c9fee7612dba6e7de055d5
### Description
This PR adds the required IR for DB to DB joins, based on @paf31 and @0x777 's `feature/db-to-db` branch.
To do so, it also refactors the IR to introduce a new type parameter, `r`, which is used to recursively constructs the `v` parameter of remote QueryDBs. When collecting remote joins, we replace `r` with `Const Void`, indicating at the type level that there cannot be any leftover remote join.
Furthermore, this PR refactors IR.Select for readability, moves some code from IR.Root to IR.Select to avoid having to deal with circular dependencies, and makes it compile by adding `error` in all new cases in the execution pipeline.
The diff doesn't make it clear, but most of Select.hs is actually unchanged. Declarations have just been reordered by topic, in the following order:
- type declarations
- instance declarations
- type aliases
- constructor functions
- traverse functions
https://github.com/hasura/graphql-engine-mono/pull/1580
Co-authored-by: Phil Freeman <630306+paf31@users.noreply.github.com>
GitOrigin-RevId: bbdcb4119cec8bb3fc32f1294f91b8dea0728721
Remote relationships are now supported on SQL Server and BigQuery. The major change though is the re-architecture of remote join execution logic. Prior to this PR, each backend is responsible for processing the remote relationships that are part of their AST.
This is not ideal as there is nothing specific about a remote join's execution that ties it to a backend. The only backend specific part is whether or not the specification of the remote relationship is valid (i.e, we'll need to validate whether the scalars are compatible).
The approach now changes to this:
1. Before delegating the AST to the backend, we traverse the AST, collect all the remote joins while modifying the AST to add necessary join fields where needed.
1. Once the remote joins are collected from the AST, the database call is made to fetch the response. The necessary data for the remote join(s) is collected from the database's response and one or more remote schema calls are constructed as necessary.
1. The remote schema calls are then executed and the data from the database and from the remote schemas is joined to produce the final response.
### Known issues
1. Ideally the traversal of the IR to collect remote joins should return an AST which does not include remote join fields. This operation can be type safe but isn't taken up as part of the PR.
1. There is a lot of code duplication between `Transport/HTTP.hs` and `Transport/Websocket.hs` which needs to be fixed ASAP. This too hasn't been taken up by this PR.
1. The type which represents the execution plan is only modified to handle our current remote joins and as such it will have to be changed to accommodate general remote joins.
1. Use of lenses would have reduced the boilerplate code to collect remote joins from the base AST.
1. The current remote join logic assumes that the join columns of a remote relationship appear with their names in the database response. This however is incorrect as they could be aliased. This can be taken up by anyone, I've left a comment in the code.
### Notes to the reviewers
I think it is best reviewed commit by commit.
1. The first one is very straight forward.
1. The second one refactors the remote join execution logic but other than moving things around, it doesn't change the user facing functionality. This moves Postgres specific parts to `Backends/Postgres` module from `Execute`. Some IR related code to `Hasura.RQL.IR` module. Simplifies various type class function signatures as a backend doesn't have to handle remote joins anymore
1. The third one fixes partial case matches that for some weird reason weren't shown as warnings before this refactor
1. The fourth one generalizes the validation logic of remote relationships and implements `scalarTypeGraphQLName` function on SQL Server and BigQuery which is used by the validation logic. This enables remote relationships on BigQuery and SQL Server.
https://github.com/hasura/graphql-engine-mono/pull/1497
GitOrigin-RevId: 77dd8eed326602b16e9a8496f52f46d22b795598
This reverts the remote schema type customisation and namespacing feature temporarily as we test for certain conditions.
GitOrigin-RevId: f8ee97233da4597f703970c3998664c03582d8e7
>
### Description
>
### Changelog
- [x] `CHANGELOG.md` is updated with user-facing content relevant to this PR. If no changelog is required, then add the `no-changelog-required` label.
### Affected components
- [x] Server
### Related Issues
->
Fixes#1528
### Solution and Design
>
Only replace connection configuration instead of replacing entire metadata with empty one.
GitOrigin-RevId: f9a16dcc7b1219ec1af915bf083622fcb7dde69a
event catalog:
- `hdb_catalog` is no longer automatically created
- catalog is initialised when the first event trigger is created
- catalog initialisation is done during the schema cache build, using `ArrowCache` so it is only run in response to a change to the set of event triggers
event queue:
- `processEventQueue` thread is prevented from starting when `HASURA_GRAPHQL_EVENTS_FETCH_INTERVAL=0`
- `processEventQueue` thread only processes sources for which at least one event trigger exists in some table in the source
Co-authored-by: Anon Ray <616387+ecthiender@users.noreply.github.com>
GitOrigin-RevId: 73f256465d62490cd2b59dcd074718679993d4fe
