GraphQL Java implementation
We are pleased to announce the release of graphql-java v22.0.
Thanks to everyone in the community who contributed to the release, whether that was code, helping to report issues, or participating in discussions.
This is a breaking change release.
The graphql-java team takes breaking changes very seriously but in the name of performance we have made some significant breaking changes in this release.
Past releases have been very much performance focused and this one is no different. However, this release is aiming to reduce memory pressure more than reduce pure CPU usage. When the graphql-java engine is running, if it produces less objects it will ultimately run faster because of reduced memory pressure and less garbage to collect.
The engine has been changed in two major ways that reduce memory pressure.
The first was that all values that come back got wrapped internally into a ExecutionResult
object where the data
attribute was the value. This was a carry over from some very early GraphQL code but was unnecessary and hence has been removed. The follow on effect of this is that some graphql.execution.ExecutionStrategy
protected methods and graphql.execution.instrumentation.Instrumentation
methods used to receive and return ExecutionResult
values and no longer do, which is an API breaking change. We have made this breaking changes in the name of memory pressure performance.
The second major change is that the engine no longer exclusively uses java.util.concurrent.CompletableFuture
s when composing together results. Let us explain the past code first so we can discuss the new code.
CompletableFuture
is a fantastic construct because it represents a promise to a value and it can also hold an exceptional state inside itself. Async programming with CompletableFuture
is viral. If stage 1 of some compute process returns a CompletableFuture
then stage 2 and 3 and 4 are likely to as well to ensure everything is asynchronous.
We use to take values that were not asynchronous (such as DataFetcher that returned a simple in memory object) and wrap them in a CompletableFuture
so that all of the other code composed together using CompletableFuture
methods like .thenApply()
and .thenCompose
and so on. The code is cleaner if you use all CompletableFuture
code patterns.
However many objects in a GraphQL request are not asynchronous but rather materialised objects in memory. Scalars, enums and list are often just values immediately available to be used and allocating a CompletableFuture
makes the code easier to write but it has a memory pressure cost.
So we have sacrificed cleaner code for more memory performant code.
graphql-java engine graphql.execution.ExecutionStrategy
methods now just return Object
where that object might be either a CompletableFuture
or a materialised value.
private Object /*CompletableFuture<FetchedValue> | FetchedValue>*/
fetchField(GraphQLFieldDefinition fieldDef, ExecutionContext executionContext, ExecutionStrategyParameters parameters) {
Notice we have lost type safety here. In the past this would have only been CompletableFuture<FetchedValue>
and hence been both type safe and async composable.
Now the caller of that method has to handle the async case where it might be a CompletableFuture<FetchedValue>
AND the materialised value case where it might be a FetchedValue
but as most simple fields in GraphQL are in fact materialised values, this is worth the less clean code.
DataFetchers
can of course continue to return CompletableFuture
values and they will be handled in a polymorphic manner.
The upshot of all this work is that the graphql-java engine allocated way less CompletableFuture
values and hence reduces the amount of memory used.
The above changes now mean means that before graphql.execution.instrumentation.InstrumentationContext
used to be given a CompletableFuture
but now no longer does
void onDispatched(CompletableFuture<T> result);
is now
void onDispatched();
if you previously used the CompletableFuture
to know when something was completed, well InstrumentationContext
has the same semantics because it's completed method is similar in that it presents a value or an exception
void onCompleted(T result, Throwable t);
graphql.execution.instrumentation.Instrumentation
also had a lot of deprecated methods in place and these have been removed since the more performant shape of passing in graphql.execution.instrumentation.InstrumentationState
has been in place for quite a few releases.
Some of the methods that received ExecutionResult
wrapped values have also changed as mentioned above.
Instrumentation
is probably the area that needs the most attention in terms of breaking changes. If you have not moved off the deprecated methods, your custom Instrumentation
s will no longer compile or run.
Our friends at Netflix provided a PR that interns certain key strings like "field names" so that we create less String instances when processing field names in queries that we know must be previously interned in the schema.
https://github.com/graphql-java/graphql-java/pull/3504
Support for the @defer
directive has been added in an experimental fashion. While @defer
is still not in the released GraphQL specification, we have judged it mature enough to support at this stage and the graphql-js
reference implementation has support for it.
https://github.com/graphql/graphql-wg/blob/main/rfcs/DeferStream.md
At this stage we have not yet supported @stream
but this is likely to be included in a future release.
There are quite a few API breaking changes in this release. In fact there are 22 PRs containing breaking API changes.
We have made changes to String, Boolean, Float, and Int parseValue
coercion, to be consistent with the reference JS implementation. The key change is parseValue
is now stricter on accepted inputs.
parseValue
now requires input of type String
. For example, a Number
input 123
or a Boolean
input true
will no longer be accepted.parseValue
now requires input of type Boolean
. For example, a String
input "true"
will no longer be accepted.parseValue
now requires input of type Number
. For example, a String
input "3.14"
will no longer be accepted.parseValue
now requires input of type Number
. For example, a String
input "42"
will no longer be accepted.This is a breaking change. To help you migrate, in version 21.0, we introduced the InputInterceptor https://github.com/graphql-java/graphql-java/pull/3188 (and an implementation LegacyCoercingInputInterceptor https://github.com/graphql-java/graphql-java/pull/3218) to provide a migration pathway. You can use this interceptor to monitor and modify values.
For more, see https://github.com/graphql-java/graphql-java/pull/3553 JS reference implementation: https://github.com/graphql/graphql-js/blob/main/src/type/scalars.ts
Many methods that have been deprecated for a long time, sometimes even up to 6 years, have finally been removed.
The CompletableFuture
unwrapping work mentioned above changed many methods in the graphql.execution.ExecutionStrategy
classes but we don't expect this affect many people since very few people write their own engines.
That CompletableFuture
unwrapping work also had knock on effects as mentioned above on graphql.execution.instrumentation.Instrumentation
and hence this is the most likely place for there to be compatibility challenges in existing code.
The code to dispatch org.dataloader.DataLoader
s used to be an instrumentation called DataLoadersDataLoaderDispatcherInstrumentation
and it was automatically added at runtime. This approach has been removed.
The equivalent code is now built into the graphql-java engine itself. DataLoader
s can now always be used without any special setup. This also allows the code to be more performant in how DataLoader
s are dispatched.
Previously, the graphql-java engine would log at DEBUG level certain errors or when fields get fetched. This has not proven used for from a support point to the graphql-java team and also has a compliance cost in that user generated content (UGC) and personally identifying information (PII) could end up being logged, which may not be allowed under regimes like European General Data Protection Regulation (GDPR).
If you want to log now we suggest you invest in a Instrumentation
that logs key events and you can there for log what you want and in a compliant manner of your choosing.
https://github.com/graphql-java/graphql-java/pull/3403
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v21.5...v22.0
This is a special release to add further limits to introspection queries.
This release contains a backport of PR #3539.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v21.4...v21.5
This is a special release to add further limits to introspection queries.
This release contains a backport of PR #3539.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v20.8...v20.9
This is a special release to add further limits to introspection queries.
This release contains a backport of PR #3539.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v19.10...v19.11
This is a special release to help control introspection queries.
This release adds a default check for introspection queries, to check that they are sensible. This feature is a backport of https://github.com/graphql-java/graphql-java/pull/3526 and https://github.com/graphql-java/graphql-java/pull/3527.
This release also adds an optional maximum result nodes limit, which is a backport of https://github.com/graphql-java/graphql-java/pull/3525.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v21.3...v21.4
This is a special release to help control introspection queries.
This release adds a default check for introspection queries, to check that they are sensible. This feature is a backport of https://github.com/graphql-java/graphql-java/pull/3526 and https://github.com/graphql-java/graphql-java/pull/3527.
This release also adds an optional maximum result nodes limit, which is a backport of https://github.com/graphql-java/graphql-java/pull/3525.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v20.7...v20.8
This is a special release to help control introspection queries.
This release adds a default check for introspection queries, to check that they are sensible. This feature is a backport of https://github.com/graphql-java/graphql-java/pull/3526 and https://github.com/graphql-java/graphql-java/pull/3527.
This release also adds an optional maximum result nodes limit, which is a backport of https://github.com/graphql-java/graphql-java/pull/3525.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v19.9...v19.10
A small bugfix release on top of 21.2, which includes correct unwrapping of non-null input types for @oneOf
.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v21.2...v21.3
This is a small bugfix release which includes a backport of PR #3334, which fixes a type unwrapping bug.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v19.8...v19.9
This is a small bugfix release which includes a backport of PR #3334, which fixes a type unwrapping bug.
Full Changelog: https://github.com/graphql-java/graphql-java/compare/v20.6...v20.7