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
Generate more Metadata Inconsistencies instead of startup failures. Specifically this means that
- errors retrieving the main query of an executable GraphQL document, and
- errors during fragment inlining
no longer fail irrecoverably.
This also makes more parts of `buildSchemaCacheRule` into pure code, which is always nice.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/7234
GitOrigin-RevId: aebf636c2fb1aad1c2df9a37f7d0b67c1ee40c42
Dependencies seem to get concatenated very often, so let's use a data structure that supports efficient concatenation.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/7050
GitOrigin-RevId: 6331963f99f17d1b908a6038318d8c4834cf4dd7
## Description ✍️
This PR introduces a new feature to enable/disable event triggers during logical replication of table data for PostgreSQL and MS-SQL data sources. We introduce a new field `trigger_on_replication` in the `*_create_event_trigger` metadata API. By default the event triggers will not fire for logical data replication.
## Changelog ✍️
__Component__ : server
__Type__: feature
__Product__: community-edition
### Short Changelog
Add option to enable/disable event triggers on logically replicated tables
### Related Issues ✍
https://github.com/hasura/graphql-engine/issues/8814https://hasurahq.atlassian.net/browse/GS-252
### Solution and Design
- By default, triggers do **not** fire when the session mode is `replica` in Postgres, so if the `triggerOnReplication` is set to `true` for an event trigger we run the query `ALTER TABLE #{tableTxt} ENABLE ALWAYS TRIGGER #{triggerNameTxt};` so that the trigger fires always irrespective of the `session_replication_role`
- By default, triggers do fire in case of replication in MS-SQL, so if the `triggerOnReplication` is set to `false` for an event trigger we add a clause `NOT FOR REPLICATION` to the the SQL when the trigger is created/altered, which sets the `is_not_for_replication` for the trigger as `true` and it does not fire during logical replication.
### Steps to test and verify ✍
- Run hspec integration tests for HGE
## Server checklist ✍
### Metadata ✍
Does this PR add a new Metadata feature?
- ✅ Yes
- Does `export_metadata`/`replace_metadata` supports the new metadata added?
- ✅
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6953
Co-authored-by: Puru Gupta <32328846+purugupta99@users.noreply.github.com>
Co-authored-by: Sean Park-Ross <94021366+seanparkross@users.noreply.github.com>
GitOrigin-RevId: 92731328a2bbdcad2302c829f26f9acb33c36135
Mostly trying to avoid tricky `Arrows` syntax, and unnecessary use of the `Hasura.Incremental` framework.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6997
GitOrigin-RevId: 9a2f5883e7e29af164e1581049ae003afec2cbe4
I encountered this dead code while doing other things: it's a type class with a single method which is never called. Deleting the type class allows us to simplify `TableCoreCacheRT` and `TableCacheRT`
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/7075
GitOrigin-RevId: 121320349c478a93717b0706037553d8406cbfa9
This increases the speed of `create_query_collection` and `add_collection_to_allowlist` by a factor ~~10~~ 65, by caching the in-memory GraphQL schema. This speedup also applies more broadly to Metadata changes relating to:
- allowlists
- query collections
- cron triggers
- REST endpoints
- API limits
- metrics config
- GraphQL introspection options
- TLS allow lists
- OpenTelemetry
When is construction of the in-memory GraphQL schema cached between Metadata operations?
Before this PR, **never**! It's rebuilt fully, for every role, on every Metadata operation.
However, there are many Metadata operations that don't influence the GraphQL schema. So we should be caching its construction.
The `Hasura.Incremental` framework allows us to cache such constructions: whenever we have an arrow `Rule m a b`, where `a` is the input to the arrow and `b` the output, we can use the `Inc.cache` combinator to obtain a new arrow which is only re-executed when the input `a` changes in a material way. To test this, `a` needs an `Eq` instance. (Before hasura/graphql-engine-mono#6877, this was a `Cacheable` type class which has now been removed.)
We can't simply apply `Inc.cache` to the "Steps 3 and 4" in `buildSchemaCacheRule`, because the inputs (components of `BuildOutputs` such as `SourceCache`) don't have an `Eq` instance.
So the changes to `buildSchemaCacheRule` restructure the code so that the input to "Step 1", namely the Metadata, can be used as a caching key instead, so that `Inc.cache` can be applied to the whole sequence of steps.
That works to cache construction of the GraphQL schema, but it means that now only those Metadata operations that _don't_ influence any of the products of steps 1-4 can use a cached build of the GraphQL schema. The most important intermediate product is `BuildOutputs`. So now the exercise becomes to minimize the amount of stuff stored in `BuildOutputs`, so that as many Metadata operations as possible can be handled outside of the codepath that produces a GraphQL schema.
Per hasura/graphql-engine-mono#6609, the `BuildOutputs` structure is too big, and stores things unnecessarily. Refer to the PR description there for reasoning - the same logic applies to this PR, and simply goes a few steps further. In doing so, it can benefit from hasura/graphql-engine-mono#6765, which allows us to verify at compile time that certain Schema Cache building steps _don't_ generate "Metadata dependencies". If a certain Metadata dependency is never generated, we don't need to handle that case in `deleteMetadataObject`. Thus such intermediate products don't need to be passed through `resolveDependencies`, and thus they don't need to be stored in `BuildOutputs`, and thus their rebuild won't trigger a GraphQL schema rebuild.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6613
GitOrigin-RevId: 27d2e69d3461bd4c32f08febef9995c0369fab3a
What is the `Cacheable` type class about?
```haskell
class Eq a => Cacheable a where
unchanged :: Accesses -> a -> a -> Bool
default unchanged :: (Generic a, GCacheable (Rep a)) => Accesses -> a -> a -> Bool
unchanged accesses a b = gunchanged (from a) (from b) accesses
```
Its only method is an alternative to `(==)`. The added value of `unchanged` (and the additional `Accesses` argument) arises _only_ for one type, namely `Dependency`. Indeed, the `Cacheable (Dependency a)` instance is non-trivial, whereas every other `Cacheable` instance is completely boilerplate (and indeed either generated from `Generic`, or simply `unchanged _ = (==)`). The `Cacheable (Dependency a)` instance is the only one where the `Accesses` argument is not just passed onwards.
The only callsite of the `unchanged` method is in the `ArrowCache (Rule m)` method. That is to say that the `Cacheable` type class is used to decide when we can re-use parts of the schema cache between Metadata operations.
So what is the `Cacheable (Dependency a)` instance about? Normally, the output of a `Rule m a b` is re-used when the new input (of type `a`) is equal to the old one. But sometimes, that's too coarse: it might be that a certain `Rule m a b` only depends on a small part of its input of type `a`. A `Dependency` allows us to spell out what parts of `a` are being depended on, and these parts are recorded as values of types `Access a` in the state `Accesses`.
If the input `a` changes, but not in a way that touches the recorded `Accesses`, then the output `b` of that rule can be re-used without recomputing.
So now you understand _why_ we're passing `Accesses` to the `unchanged` method: `unchanged` is an equality check in disguise that just needs some additional context.
But we don't need to pass `Accesses` as a function argument. We can use the `reflection` package to pass it as type-level context. So the core of this PR is that we change the instance declaration from
```haskell
instance (Cacheable a) => Cacheable (Dependency a) where
```
to
```haskell
instance (Given Accesses, Eq a) => Eq (Dependency a) where
```
and use `(==)` instead of `unchanged`.
If you haven't seen `reflection` before: it's like a `MonadReader`, but it doesn't require a `Monad`.
In order to pass the current `Accesses` value, instead of simply passing the `Accesses` as a function argument, we need to instantiate the `Given Accesses` context. We use the `give` method from the `reflection` package for that.
```haskell
give :: forall r. Accesses -> (Given Accesses => r) -> r
unchanged :: (Given Accesses => Eq a) => Accesses -> a -> a -> Bool
unchanged accesses a b = give accesses (a == b)
```
With these three components in place, we can delete the `Cacheable` type class entirely.
The remainder of this PR is just to remove the `Cacheable` type class and its instances.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6877
GitOrigin-RevId: 7125f5e11d856e7672ab810a23d5bf5ad176e77f
- Avoid a few banana brackets `(| ... |)`, often by just using local `let` bindings
- Use proper `Arrows` syntax rather than helpers like `>->`
- Use monadic `do` syntax instead of `Arrows` syntax where possible
- Avoid `traverseA @Maybe`, in favor of a `case`
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6751
GitOrigin-RevId: c07b22a1a259db6d135486ec71a716705e280717
