graphql-engine/server/src-lib/Hasura/GraphQL/Execute/Mutation.hs
Antoine Leblanc 6e574f1bbe harmonize network manager handling
## 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
2023-02-22 15:55:54 +00:00

161 lines
6.6 KiB
Haskell

module Hasura.GraphQL.Execute.Mutation
( convertMutationSelectionSet,
)
where
import Data.Environment qualified as Env
import Data.HashMap.Strict qualified as Map
import Data.HashMap.Strict.InsOrd qualified as OMap
import Data.Tagged qualified as Tagged
import Hasura.Base.Error
import Hasura.GraphQL.Context
import Hasura.GraphQL.Execute.Action
import Hasura.GraphQL.Execute.Backend
import Hasura.GraphQL.Execute.Common
import Hasura.GraphQL.Execute.Instances ()
import Hasura.GraphQL.Execute.Remote
import Hasura.GraphQL.Execute.RemoteJoin.Collect qualified as RJ
import Hasura.GraphQL.Execute.Resolve
import Hasura.GraphQL.Namespace
import Hasura.GraphQL.ParameterizedQueryHash
import Hasura.GraphQL.Parser.Directives
import Hasura.GraphQL.Schema.Parser (runParse, toQErr)
import Hasura.GraphQL.Transport.HTTP.Protocol qualified as GH
import Hasura.Logging qualified as L
import Hasura.Metadata.Class
import Hasura.Prelude
import Hasura.QueryTags
import Hasura.RQL.IR
import Hasura.RQL.Types.Action
import Hasura.RQL.Types.Backend
import Hasura.RQL.Types.Common
import Hasura.RQL.Types.GraphqlSchemaIntrospection
import Hasura.RQL.Types.QueryTags
import Hasura.SQL.AnyBackend qualified as AB
import Hasura.Server.Prometheus (PrometheusMetrics (..))
import Hasura.Server.Types (RequestId (..))
import Hasura.Services
import Hasura.Session
import Hasura.Tracing qualified as Tracing
import Language.GraphQL.Draft.Syntax qualified as G
import Network.HTTP.Types qualified as HTTP
convertMutationAction ::
( MonadIO m,
MonadError QErr m,
MonadMetadataStorage m,
ProvidesNetwork m
) =>
Env.Environment ->
L.Logger L.Hasura ->
PrometheusMetrics ->
UserInfo ->
HTTP.RequestHeaders ->
Maybe GH.GQLQueryText ->
ActionMutation Void ->
m ActionExecutionPlan
convertMutationAction env logger prometheusMetrics userInfo reqHeaders gqlQueryText action = do
httpManager <- askHTTPManager
case action of
AMSync s ->
pure $ AEPSync $ resolveActionExecution httpManager env logger prometheusMetrics userInfo s actionExecContext gqlQueryText
AMAsync s ->
AEPAsyncMutation <$> resolveActionMutationAsync s reqHeaders userSession
where
userSession = _uiSession userInfo
actionExecContext = ActionExecContext reqHeaders (_uiSession userInfo)
convertMutationSelectionSet ::
forall m.
( Tracing.MonadTrace m,
MonadIO m,
MonadError QErr m,
MonadMetadataStorage m,
MonadGQLExecutionCheck m,
MonadQueryTags m,
ProvidesNetwork m
) =>
Env.Environment ->
L.Logger L.Hasura ->
PrometheusMetrics ->
GQLContext ->
SQLGenCtx ->
UserInfo ->
HTTP.RequestHeaders ->
[G.Directive G.Name] ->
G.SelectionSet G.NoFragments G.Name ->
[G.VariableDefinition] ->
GH.GQLReqUnparsed ->
SetGraphqlIntrospectionOptions ->
RequestId ->
-- | Graphql Operation Name
Maybe G.Name ->
m (ExecutionPlan, ParameterizedQueryHash)
convertMutationSelectionSet
env
logger
prometheusMetrics
gqlContext
SQLGenCtx {stringifyNum}
userInfo
reqHeaders
directives
fields
varDefs
gqlUnparsed
introspectionDisabledRoles
reqId
maybeOperationName = do
mutationParser <-
onNothing (gqlMutationParser gqlContext) $
throw400 ValidationFailed "no mutations exist"
(resolvedDirectives, resolvedSelSet) <- resolveVariables varDefs (fromMaybe Map.empty (GH._grVariables gqlUnparsed)) directives fields
-- Parse the GraphQL query into the RQL AST
unpreparedQueries ::
RootFieldMap (MutationRootField UnpreparedValue) <-
liftEither $ mutationParser resolvedSelSet
-- Process directives on the mutation
_dirMap <- toQErr $ runParse (parseDirectives customDirectives (G.DLExecutable G.EDLMUTATION) resolvedDirectives)
let parameterizedQueryHash = calculateParameterizedQueryHash resolvedSelSet
resolveExecutionSteps rootFieldName rootFieldUnpreparedValue = do
case rootFieldUnpreparedValue of
RFDB sourceName exists ->
AB.dispatchAnyBackend @BackendExecute
exists
\(SourceConfigWith (sourceConfig :: SourceConfig b) queryTagsConfig (MDBR db)) -> do
let mReqId =
case _qtcOmitRequestId <$> queryTagsConfig of
-- we include the request id only if a user explicitly wishes for it to be included.
Just False -> Just reqId
_ -> Nothing
mutationQueryTagsAttributes = encodeQueryTags $ QTMutation $ MutationMetadata mReqId maybeOperationName rootFieldName parameterizedQueryHash
queryTagsComment = Tagged.untag $ createQueryTags @m mutationQueryTagsAttributes queryTagsConfig
(noRelsDBAST, remoteJoins) = RJ.getRemoteJoinsMutationDB db
dbStepInfo <- flip runReaderT queryTagsComment $ mkDBMutationPlan @b userInfo env stringifyNum sourceName sourceConfig noRelsDBAST reqHeaders maybeOperationName
pure $ ExecStepDB [] (AB.mkAnyBackend dbStepInfo) remoteJoins
RFRemote remoteField -> do
RemoteSchemaRootField remoteSchemaInfo resultCustomizer resolvedRemoteField <- runVariableCache $ resolveRemoteField userInfo remoteField
let (noRelsRemoteField, remoteJoins) = RJ.getRemoteJoinsGraphQLField resolvedRemoteField
pure $
buildExecStepRemote remoteSchemaInfo resultCustomizer G.OperationTypeMutation noRelsRemoteField remoteJoins (GH._grOperationName gqlUnparsed)
RFAction action -> do
let (noRelsDBAST, remoteJoins) = RJ.getRemoteJoinsActionMutation action
(actionName, _fch) <- pure $ case noRelsDBAST of
AMSync s -> (_aaeName s, _aaeForwardClientHeaders s)
AMAsync s -> (_aamaName s, _aamaForwardClientHeaders s)
plan <- convertMutationAction env logger prometheusMetrics userInfo reqHeaders (Just (GH._grQuery gqlUnparsed)) noRelsDBAST
pure $ ExecStepAction plan (ActionsInfo actionName _fch) remoteJoins -- `_fch` represents the `forward_client_headers` option from the action
-- definition which is currently being ignored for actions that are mutations
RFRaw customFieldVal -> flip onLeft throwError =<< executeIntrospection userInfo customFieldVal introspectionDisabledRoles
RFMulti lst -> do
allSteps <- traverse (resolveExecutionSteps rootFieldName) lst
pure $ ExecStepMulti allSteps
-- Transform the RQL AST into a prepared SQL query
txs <- flip OMap.traverseWithKey unpreparedQueries $ resolveExecutionSteps
return (txs, parameterizedQueryHash)