### Description
This PR adds the ability to perform remote joins from remote schemas in the engine. To do so, we alter the definition of an `ExecutionStep` targeting a remote schema: the `ExecStepRemote` constructor now expects a `Maybe RemoteJoins`. This new argument is used when processing the execution step, in the transport layer (either `Transport.HTTP` or `Transport.WebSocket`).
For this `Maybe RemoteJoins` to be extracted from a parsed query, this PR also extends the `Execute.RemoteJoin.Collect` module, to implement "collection" from a selection set. Not only do those new functions extract the remote joins, but they also apply all necessary transformations to the selection sets (such as inserting the necessary "phantom" fields used as join keys).
Finally in `Execute.RemoteJoin.Join`, we make two changes. First, we now always look for nested remote joins, regardless of whether the join we just performed went to a source or a remote schema; and second we adapt our join tree logic according to the special cases that were added to deal with remote server edge cases.
Additionally, this PR refactors / cleans / documents `Execute.RemoteJoin.RemoteServer`. This is not required as part of this change and could be moved to a separate PR if needed (a similar cleanup of `Join` is done independently in #3894). It also introduces a draft of a new documentation page for this project, that will be refined in the release PR that ships the feature (either #3069 or a copy of it).
While this PR extends the engine, it doesn't plug such relationships in the schema, meaning that, as of this PR, the new code paths in `Join` are technically unreachable. Adding the corresponding schema code and, ultimately, enabling the metadata API will be done in subsequent PRs.
### Keeping track of concrete type names
The main change this PR makes to the existing `Join` code is to handle a new reserved field we sometimes use when targeting remote servers: the `__hasura_internal_typename` field. In short, a GraphQL selection set can sometimes "branch" based on the concrete "runtime type" of the object on which the selection happens:
```graphql
query {
author(id: 53478) {
... on Writer {
name
articles {
title
}
}
... on Artist {
name
articles {
title
}
}
}
}
```
If both of those `articles` are remote joins, we need to be able, when we get the answer, to differentiate between the two different cases. We do this by asking for `__typename`, to be able to decide if we're in the `Writer` or the `Artist` branch of the query.
To avoid further processing / customization of results, we only insert this `__hasura_internal_typename: __typename` field in the query in the case of unions of interfaces AND if we have the guarantee that we will processing the request as part of the remote joins "folding": that is, if there's any remote join in this branch in the tree. Otherwise, we don't insert the field, and we leave that part of the response untouched.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3810
GitOrigin-RevId: 89aaf16274d68e26ad3730b80c2d2fdc2896b96c
### Description
Several libraries define `catMaybes` as `mapMaybe id`. We had it defined in `Data.HashMap.Strict.Extended` already. This small PR also defines it in `Extended` modules for other containers and replaces every occurrence of `mapMaybe id` accordingly.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3884
GitOrigin-RevId: d222a2ca2f4eb9b725b20450a62a626d3886dbf4
### Description
There were several places in the codebase where we would either implement a generic container, or express the need for one. This PR extracts / creates all relevant containers, and adapts the relevant parts of the code to make use of said new generic containers. More specifically, it introduces the following modules:
- `Data.Set.Extended`, for new functions on `Data.Set`
- `Data.HashMap.Strict.Multi`, for hash maps that accept multiple values
- `Data.HashMap.Strict.NonEmpty`, for hash maps that can never be constructed as empty
- `Data.Trie`, for a generic implementation of a prefix tree
This PR makes use of those new containers in the following parts of the code:
- `Hasura.GraphQL.Execute.RemoteJoin.Types`
- `Hasura.RQL.Types.Endpoint*`
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3828
GitOrigin-RevId: e6c1b971bcb3f5ab66bc91d0fa4d0e9df7a0c6c6
#### TODO
- [x] fix `hashable >= 1.3.1` serialization ordering issue [^1]
- `test_graphql_mutations.py::TestGraphQLMutateEnums` was failing
- [x] fix `unordered-containers` serialization ordering issue [^2]
- `test_graphql_queries.py` was failing on Citus
- [ ] verify that no new failures have been introduced
- [ ] open issues to fix the above
- identify test cases that "leak" implementation details by depending on `hashable` instance ordering
- bump `hashable >= 1.3.1` and update test cases with new ordering OR modify them so that ordering is stable
- bump `unordered-containers >= 0.2.15.0` and update test cases with new ordering OR modify them so that ordering is stable
- one of the test cases was failing on string equality comparison for a generated Citus query
- we probably don't want to _actually_ do this unless there are _very specific_ guarantees we want to make about generated query structure
---
Just what it says on the tin.
https://github.com/hasura/graphql-engine-mono/pull/3538 updated the freeze file a few weeks ago, but it looks like the index state hadn't been updated since December so a lot of stuff that had newer versions didn't get updated.
---
EDIT: I should add, the motivation for doing this in the first place is that `hspec > 2.8.4` now supports specifying filtering spec trees based on patterns provided by the `HSPEC_MATCH` environment variable.
For example, one could have a script that executes the following:
```
HSPEC_MATCH="PostgreSQL" \
ghcid \
--command \
'cabal repl graphql-engine:test:tests-hspec \
--repl-option -O0 \
--repl-option -fobject-code' \
--test "main"
```
...which will loop on typechecking the `tests-hspec` component, and then as soon as it passes (i.e. no warnings or errors) will run _only_ the `PostgreSQL` sub-components.
[^1]: `hashable >= 1.3.1.0` [updated its default salts](https://github.com/haskell-unordered-containers/hashable/pull/196), which [broke serialization ordering](https://github.com/haskell/aeson/issues/837)
[^2]: `unordered-containers >= 0.2.16.0` [introduced changes to some of its internal functions](https://hackage.haskell.org/package/unordered-containers-0.2.16.0/changelog) which seem like they could have affected serialization stability
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3672
GitOrigin-RevId: bbd1d48c73db4021913f0b5345b7315a8d6525d3
- consistent qualified imports
- less convoluted initialization of pro logging HTTP manager
- pass pro HTTP manager directly instead of via Has
- remove some dead healthcheck code
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3639
GitOrigin-RevId: dfa7b9c62d1842a07a8514cdb77f1ed86064fb06
### Description
This PR is the result of a discussion in #3363. Namely, we would like to remove all uses of `unsafeMkName`, or at the very least document every single one of them, to avoid similar issues. To do so, this PR does the following:
- it adds a hlint suggestion not to use that function:
- suggestions don't mark the PR as failed, but will be shown at review time
- it is possible to disable that hint with `{- HLINT ignore myFunction "unsafe" -}`
- wherever possible, it removes uses of `unsafeMkName` in favour of `mkName`
- it adds a comment with a tracking issue for the two remaining uses:
- #3478
- #3479
### Remaining work
- discuss whether this hint should make the linter step fail, since the linter step isn't required to merge anyway, and there is a way to disable the hint wherever we think the use of that function is acceptable
- check that none of those uses were load-bearing and result in errors now
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3480
GitOrigin-RevId: 0a7e3e9d1a48185764c04ab61e34b58273af347c
The only real use was for the dubious multitenant option
--consoleAssetsVersion, which actually overrode not just
the assets version. I.e., as far as I can tell, if you pass
--consoleAssetsVersion to multitenant, that version will
also make it into e.g. HTTP client user agent headers as
the proper graphql-engine version.
I'm dropping that option, since it seems unused in production
and I don't want to go to the effort of fixing it, but am happy
to look into that if folks feels strongly that it should be
kept.
(Reason for attacking this is that I was looking into http
client things around blacklisting, and the versioning thing
is a bit painful around http client headers.)
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/2458
GitOrigin-RevId: a02b05557124bdba9f65e96b3aa2746aeee03f4a
This commit applies ormolu to the whole Haskell code base by running `make format`.
For in-flight branches, simply merging changes from `main` will result in merge conflicts.
To avoid this, update your branch using the following instructions. Replace `<format-commit>`
by the hash of *this* commit.
$ git checkout my-feature-branch
$ git merge <format-commit>^ # and resolve conflicts normally
$ make format
$ git commit -a -m "reformat with ormolu"
$ git merge -s ours post-ormolu
https://github.com/hasura/graphql-engine-mono/pull/2404
GitOrigin-RevId: 75049f5c12f430c615eafb4c6b8e83e371e01c8e
### 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
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
