### Motivation
While we strive to write clear code, we have historically struggled at Hasura with having very different styles and standards across the codebase. There's been efforts to standardize our coding style, we have an official styleguide that isn't maintained as closely as it should... We still have some work in front of us.
However, in the last ~year or so, there's been a huge push towards incrementally improving the situation. As part of this we've been blocking PRs that don't add enough comments, or don't improve the files that they touch.
While looking at `Hasura.GraphQL.Analyse`, it became apparent that this file did not meet the engineering standards that I would expect to see addressed during a code review. Some ways in which I think it falls short:
- lack of documentation
- no clear distinction between public / internal components
- "unidiomatic" Haskell code (such as using `Either Result Error`)
While there's no problem with a file looking like this during development, those issues should have been caught at review time. The fact that they weren't indicates a problem in our process that we will need to address: code quality and maintainability is paramount, and we all need to do our part.
### Description
This PR rewrites all of `Hasura.GraphQL.Analyze`, and adapts `Hasura.Server.OpenAPI` accordingly where needed. I've attempted to clarify names and add documentation based on my understanding of the code, and to clean what was unused (such as field variables). I don't think this PR is good enough as is, and I welcome criticism where I got my comments wrong / am happy to help y'all add more.
This PR makes one small change in the way error messages are reported (and adjusts the corresponding test accordingly); each error message is now prefixed with the path within the selection set:
```
⚠️ $.test.foo.bar.baz.mizpelled: field 'mizpelled' not found in object 'Baz'
```
### Note
This PR is currently **on top of #3962**. You can preview the changes in isolation by [diffing the branches](https://github.com/hasura/graphql-engine-mono/compare/nicuveo/clean-rest-endpoint-inconsistency-check..nicuveo/rewrite-analysis).
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3963
Co-authored-by: paritosh-08 <85472423+paritosh-08@users.noreply.github.com>
GitOrigin-RevId: 5ec38e0e753f0c12096a350db0737658495e2f15
## Description
Some of the documentation/organizational changes I was putting into the suggestions for #3624 were a bit too convoluted for GitHub's suggestion interface, so I'm putting them here instead.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3910
Co-authored-by: Solomon <24038+solomon-b@users.noreply.github.com>
GitOrigin-RevId: 06e0cb08bd18e7f8b21452df0697cfd80bc56fde
### Motivation
#2338 introduced a way to validate REST queries against the metadata after a change, to properly report any inconsistency that would emerge from a change in the underlying structure of our schema. However, the way this was done was quite complex and error-prone. Namely: we would use the generated schema parsers to statically execute an introspection query, similar to the one we use for remote schemas, then parse the resulting bytestring as it were coming from a remote schema.
This led to several issues: the code was using remote schema primitives, and was associated with remote schema code, despite being unrelated, which led to absurd situations like creating fake `Variable`s whose type was also their name. A lot of the code had to deal with the fact that we might fail to re-parse our own schema. Additionally, some of it was dead code, that for some reason GHC did not warn about? But more fundamentally, this architecture decision creates a dependency between unrelated pieces of the engine: modifying the internal processing of root fields or the introspection of remote schemas now risks impacting the unrelated `OpenAPI` feature.
### Description
This PR decouples that process from the remote schema introspection logic and from the execution engine by making `Analyse` and `OpenAPI` work on the generic `G.SchemaIntrospection` instead. To accomplish this, it:
- adds `GraphQL.Parser.Schema.Convert`, to convert from our "live" schema back to a flat `SchemaIntrospection`
- persists in the schema cache the `admin` introspection generated when building the schema, and uses it both for validation and for generating the `OpenAPI`.
### Known issues and limitations
This adds a bit of memory pressure to the engine, as we persist the entire schema in the schema cache. This might be acceptable in the short-term, but we have several potential ideas going forward should this be a problem:
- cache the result of `Analyze`: when it becomes possible to build the `OpenAPI` purely with the result of `Analyze` without any additional schema information, then we could cache that instead, reducing the footprint
- caching the `OpenAPI`: if it doesn't need to change every time the endpoint is queried, then it should be possible to cache the entire `OpenAPI` object instead of the schema
- cache a copy of the `FieldParsers` used to generate the schema: as those are persisted through the GraphQL `Context`, and are the only input required to generate the `Schema`, making them accessible in the schema cache would allow us to have the exact same feature with no additional memory cost, at the price of a slightly slower and more complicated process (need to rebuild the `Schema` every time we query the OpenAPI endpoint)
- cache nothing at all, and rebuild the admin schema from scratch every time.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3962
Co-authored-by: paritosh-08 <85472423+paritosh-08@users.noreply.github.com>
GitOrigin-RevId: a8b9808170b231fdf6787983b4a9ed286cde27e0
### Description
This is it! This PR enables the Metadata API for remote relationships from remote schemas, adds tests, ~~adds documentation~~, adds an entry to the Changelog. This is the release PR that enables the feature.
### Checklist
- [ ] Tests:
- [x] RS-to-Postgres (high level)
- [x] RS-to-RS (high level)
- [x] From RS specifically (testing for edge cases)
- [x] Metadata API tests
- [ ] Unit testing the actual engine?
- [x] Changelog entry
- [ ] Documentation?
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3974
Co-authored-by: Vamshi Surabhi <6562944+0x777@users.noreply.github.com>
Co-authored-by: Vishnu Bharathi <4211715+scriptnull@users.noreply.github.com>
Co-authored-by: jkachmar <8461423+jkachmar@users.noreply.github.com>
GitOrigin-RevId: c9aebf12e6eebef8d264ea831a327b968d4be9d2
### Description
This PR extends the `RemoteSchema` parsers to also include remote relationships. This include a significant refactoring of the top level schema building blocks, since remote schemas can no longer be built in isolation: they have to be built within the same run of `MonadSchema` as the sources. It is originally taken from the changes in #3069 and was slightly adapted.
I highly recommend turning OFF whitespace in the Github UI for `Schema.hs`, since I've adjusted the indentation of two large functions.
### Warning
Given the lack of a feature flag, this PR technically **enables the feature**. While the metadata API is not plugged in, a savvy user could use `replace_metadata` to set a metadata that contains remote joins from remote schemas, and they would be enabled. Is this acceptable?
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3811
GitOrigin-RevId: a5b00f865cdb8890b0fc02b139c2ebd48929f138
### Description
This small PR improves the representation of an endpoint method from `Text` to an enum of the supported methods. Additionally, it cleans some of the instances defined on surrounding types (such as Postgres-specific instances on Endpoint types).
Due to a name conflict, this makes `RQL.Types.Endpoint` impossible to re-export from `RQL.Types`, which in turn forces several other modules to import it explicitly, which I think is fine since we want to ultimately get rid of `RQL.Types`.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3965
GitOrigin-RevId: 33869007d0d818ddf486fb61d1f6099f9dad7570
<!-- Thank you for ss in the Title above ^ -->
## Description ✍️
<!-- Please fill this se-->
<!-- Describe the changes from a user's perspective -->
Add some documentation on `ActionFieldG` type.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3945
GitOrigin-RevId: d9543ed7a8fe3ccfe9f5267c3a2ac71fb040f4db
### Description
This PR improves the `Collect` module by re-ordering the functions to make clear what is public API and what is internal implementation. Furthermore, it makes use of `traverseOf` and `traverseFields` to reduce duplication. To do so, it also introduces a few more lenses in the rest of the codebase, and uses this opportunity to harmonize some structures that were not following our naming convention.
While the diff is massive, a lot of it is just code moving around; the file is now divided into separate sections:
- entry points: IR types for which we want to run the collection
- internal monadic structure
- internal traversals: functions that do nothing but drill down further
- actual transformations: the three cases where we do actually have work to do: selection sets on which we do want to insert join columns, extract remote relationships... those functions are left unchanged by this PR
- internal helpers
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3863
GitOrigin-RevId: f7cbecfae9eed9737b62acfa5848bfcf9d4651f6
### 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
…rmance
It makes sense to try to utilize multiple threads for metadata
operations since we expect them to come one at a time (and likely at
lower load periods anyway).
As noted, although we build roles in parallel now, the admin role is
still a bottleneck. For replace_metadata on huge_schema, on my machine
I get:
BEFORE: 22.7 sec
AFTER: 13.5 sec
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3911
GitOrigin-RevId: 4d4ee6ac8b5506603e70e4fc666a3aacc054d493
### 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
### Description
This PR is one further step towards remote joins from remote schemas. It introduces a custom partial AST to represent queries to remote schemas in the IR: we now need to augment what used to be a straightforward GraphQL AST with additional information for remote join fields.
This PR does the minimal amount of work to adjust the rest of the code accordingly, using `Void` in all places that expect a type representing remote relationships.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3794
GitOrigin-RevId: 33fc317731aace71f82ad158a1951ea93350d6cc
No logic in this PR, just tidying things up (renaming the backend from `Experimental` to `DataWrapper`).
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3779
GitOrigin-RevId: f11acf563ccd8b9f16bc23c5e92da392aa4cfb2c
I discovered and removed instances of Boolean Blindness about whether json numbers should be stringified or not.
Although quite far-reaching, this is a completely mechanical change and should have no observable impact outside the server code.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3763
GitOrigin-RevId: c588891afd8a6923a135c736f6581a43a2eddbc7
TL;DR
---
We go from this:
```haskell
(|
withRecordInconsistency
( (|
modifyErrA
( do
(info, dependencies) <- liftEitherA -< buildRelInfo relDef
recordDependencies -< (metadataObject, schemaObject, dependencies)
returnA -< info
)
|) (addTableContext @b table . addRelationshipContext)
)
|) metadataObject
```
to this:
```haskell
withRecordInconsistencyM metadataObject $ do
modifyErr (addTableContext @b table . addRelationshipContext) $ do
(info, dependencies) <- liftEither $ buildRelInfo relDef
recordDependenciesM metadataObject schemaObject dependencies
return info
```
Background
---
We use Haskell's `Arrows` language extension to gain some syntactic sugar when working with `Arrow`s. `Arrow`s are a programming abstraction comparable to `Monad`s.
Unfortunately the syntactic sugar provided by this language extension is not very sweet.
This PR shows how we can sometimes avoid using `Arrow`s altogether, without loss of functionality or correctness. It is a demo of a technique that can be used to cut down the amount of `Arrows`-based code in our codebase by about half.
Approach
---
Although _in general_ not every `Monad` is an `Arrow`, specific `Arrow` instantiations are exactly as powerful as their `Monad` equivalents. Otherwise they wouldn't be very equivalent, would they?
Just like `liftEither` interprets the `Either e` monad into an arbitrary monad implementing `MonadError e`, we add `interpA` which interprets certain concrete monads such as `Writer w` into specific arrows, e.g. ones satisfying `ArrowWriter w`. This means that the part of the code that only uses such interpretable effects can be written _monadically_, and then used in _arrow_ constructions down the line.
This approach cannot be used for arrow effects which do not have a monadic equivalent. In our codebase, the only instance of this is `ArrowCache m`, implemented by the `Rule m` arrow. So code written with `ArrowCache m` in the context cannot be rewritten monadically using this technique.
See also
---
- #1827
- #2210
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3543
Co-authored-by: jkachmar <8461423+jkachmar@users.noreply.github.com>
GitOrigin-RevId: eb79619c95f7a571bce99bc144ce42ee65d08505
There are three minor cleanups here:
- The first argument to the `setMetadataInCatalog` method is always `Just`. It is thus important to avoid `Maybe`, because this means that a crucial piece of code (saving metadata) is completely untested.
- Rather than spelling them out, we can derive the `Semigroup`/`Monoid` instances for `MetadataModifier` through the `Endo` type.
- I've renamed the name of the getter of the `MetadataModifier` newtype to **r**unMetadataModifier. Using record puns, this allows us to write:
```diff
- putMetadata $ unMetadataModifier metadataModifier metadata
+ putMetadata $ runMetadataModifier metadata
```
which is nicer to read.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3703
GitOrigin-RevId: fd36b3c5202017f5afc943c01dfdd7c82c099bdd
We build the GraphQL schema by combining building blocks such as `tableSelectionSet` and `columnParser`. These building blocks individually build `{InputFields,Field,}Parser` objects. Those object specify the valid GraphQL schema.
Since the GraphQL schema is role-dependent, at some point we need to know what fragment of the GraphQL schema a specific role is allowed to access, and this is stored in `{Sel,Upd,Ins,Del}PermInfo` objects.
We have passed around these permission objects as function arguments to the schema building blocks since we first started dealing with permissions during the PDV refactor - see hasura/graphql-engine@5168b99e46 in hasura/graphql-engine#4111. This means that, for instance, `tableSelectionSet` has as its type:
```haskell
tableSelectionSet ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (Parser 'Output n (AnnotatedFields b))
```
There are three reasons to change this.
1. We often pass a `Maybe (xPermInfo b)` instead of a proper `xPermInfo b`, and it's not clear what the intended semantics of this is. Some potential improvements on the data types involved are discussed in issue hasura/graphql-engine-mono#3125.
2. In most cases we also already pass a `TableInfo b`, and together with the `MonadRole` that is usually also in scope, this means that we could look up the required permissions regardless: so passing the permissions explicitly undermines the "single source of truth" principle. Breaking this principle also makes the code more difficult to read.
3. We are working towards role-based parsers (see hasura/graphql-engine-mono#2711), where the `{InputFields,Field,}Parser` objects are constructed in a role-invariant way, so that we have a single object that can be used for all roles. In particular, this means that the schema building blocks _need_ to be constructed in a role-invariant way. While this PR doesn't accomplish that, it does reduce the amount of role-specific arguments being passed, thus fixing hasura/graphql-engine-mono#3068.
Concretely, this PR simply drops the `xPermInfo b` argument from almost all schema building blocks. Instead these objects are looked up from the `TableInfo b` as-needed. The resulting code is considerably simpler and shorter.
One way to interpret this change is as follows. Before this PR, we figured out permissions at the top-level in `Hasura.GraphQL.Schema`, passing down the obtained `xPermInfo` objects as required. After this PR, we have a bottom-up approach where the schema building blocks themselves decide whether they want to be included for a particular role.
So this moves some permission logic out of `Hasura.GraphQL.Schema`, which is very complex.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3608
GitOrigin-RevId: 51a744f34ec7d57bc8077667ae7f9cb9c4f6c962
spec: https://github.com/hasura/graphql-engine-mono/pull/2278
Briefly:
- extend metadata so that allowlist entries get a new scope field
- update `add_collection_to_allowlist` to accept this new scope field,
and adds `update_scope_of_collection_in_allowlist` to change the scope
- scope can be global or role-based; a collection is available for every
role if it is global, and available to every listed role if it is role-based
- graphql-engine-oss is aware of role-based allowlist metadata; collections
with non-global scope are treated as if they weren't in the allowlist
To run the tests:
- `cabal run graphql-engine-tests -- unit --match Allowlist`
- py-tests against pro:
- launch `graphql-engine-pro` with `HASURA_GRAPHQL_ADMIN_SECRET` and `HASURA_GRAPHQL_ENABLE_ALLOWLIST`
- `pytest test_allowlist_queries.py --hge-urls=... --pg-urls=... --hge-key=... --test-allowlist-queries --pro-tests`
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/2477
Co-authored-by: Anon Ray <616387+ecthiender@users.noreply.github.com>
Co-authored-by: Robert <132113+robx@users.noreply.github.com>
GitOrigin-RevId: 01f8026fbe59d8701e2de30986511a452fce1a99
## Description
This PR is a subset of #3069, that does roughly that #3031 was aiming to do: add the schema cache building phase for relationships from remote servers. This PR does not change any of the code that *uses* remote relationships, meaning we ignore the added schema cache information. It also contains dependency-tracking code, which was originally missing from #3031; in turn, this pulls some of the metadata API as well, since we identify remote relationships by how they were created.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3540
GitOrigin-RevId: ed962b6d07fd4adbf0a71e0d79736a4e8b422fea
