A few minor bug fixes.
Fixed a bug that could prevent subscriptions for operating correctly.
A new schema compile option, :executor, has been added;
this is an Executor used primarily when invoking
ResolverResultPromise callbacks. If omitted, a default executor is provided.
Most applications, especially those that make heavy use of
com.walmartlabs.lacinia.resolve/resolve-promise, will want to provide their own executor.
Subscription streamer functions can now be wrapped to implement field definition directives using a new schema compilation option.
Subscription streamer functions can now access the field selections (via the preview api).
This release features some significant efficiency improvements inside Lacinia.
New options have been added to com.walmartlabs.lacina.schema/compile that turn off certain checks and features
to boost performance even further.
- Previously, a resolver, including a default resolver, could return a map containing a value that was
a
ResolverResult, and Lacinia would de-reference it; this is no longer allowed, resolvers must return a value (or a value delivered by aResolverResult). A map that contains a ResolverResult is not a value. However, a value may be wrapped (.e.g, callingwith-error), as before.
A new function, com.walmartlabs.lacinia.schema/select-type, allows a type within the compiled schema to be selected;
this exposes the type, fields, arguments, and so forth, much like GraphQL introspection, but at the Clojure API level.
Some additions and incompatible changes have been made to the protocols in the com.walmartlabs.lacinia.selection
namespace; these protocols are not meant to be implemented except by the library, and prior code (from 0.38) will be
largely source compatible with the new names. Further such changes are expected.
Lacinia now detects infinite cycles caused by fragments directly, or indirectly, referring to themselves .
Previously, when multiple fragments selected the same field within a single object, the later fragments would overwrite the earlier fragments; this has now been addressed and fragments merge together as expected.
A deps.edn for the project has been added.
Optional request tracing is now designed to be compatible with Apollo GraphQL's implementation.
New support for Apollo GraphQL Federation.
The default objects names for storing operations are now Query, Mutation, and Subscription, and these must be
objects (not unions), as per the GraphQL specification.
Added function com.walmartlabs.lacinia.executor/selection which provides access to
the details about the selection, including directives and nested selections.
A new schema compilation option can be used to implement field definition directives by wrapping
field resolvers; the selection API can expose information about the field, including a field's
type system directives.
Fixed an issue where a Schema Definition Language that contained
the literal values true, false, or null would fail to parse.
Lacinia now correctly conforms to the GraphQL specification related to Errors and Non-Nullability.
It is now possible to use query variables inside a list or input object type.
Added new function com.walmartlabs.lacinia.util/inject-streamers, used to
add streamers to a schema (typically, one parsed from a GraphQL schema document).
Likewise, inject-scalar-transformers injects :parse and :serialize keys into a
scalar (complementing the inject-enum-transformers function added in 0.36.0).
Combined, these functions (plus inject-descriptions) replace the attach argument
to com.walmartlabs.lacinia.parser.schema/parse-schema which is now deprecated.
The schema parser has been updated, to allow input values (within input types) to specify defaults, and to support extending input types.
The preview API functions (selections-seq2, etc.) now recognize the @include and
@skip directives.
Exceptions thrown by resolver functions are now caught and wrapped as new exceptions that identify the field, query location and path, and field arguments. This also applies to exceptions thrown when processing the result, such as an invalid enum value returned from a resolver function.
Resolver functions can now return maps whose values are themselves ResolverResults. This can, in some cases, be easier than coordinating a parent resolver and a nested resolver.
It is now possible to provide :parse and :serialize functions for
enum types, allowing a mapping between your application's model and
the GraphQL model.
Capturing of lacinia resolver execution times has been significantly changed in an incompatible way (this feature is still experimental).
The Lacinia execution model has changed slightly to support setting a timeout on execution; most of the work now executes in a different thread. We've also increased Lacinia's ability to split work across multiple threads, along with some tiny performance improvements.
Lacinia now uses the fully qualified field and argument name as :extension data
when reporting errors in fields, field arguments, and variables.
The new function com.walmartlabs.lacinia.executor/parsed-query->context
makes it possible to use the preview API functions in the executor
namespace even before the query is executed, for example, from
a Pedestal interceptor.
New preview API function com.walmartlabs.lacinia.executor/selections-seq2
improves on selections-seq, returning the name, alias, and arguments of
each selected field.
GraphQL Schema Definition Language documents can now contain empty types, and use
extend type.
The handling of nulls, omitted variables and arguments, and default values has changed to adhere to the latest version of the specification. Non-null arguments may now have defaults, and nullable variables may be provided to non-null arguments (though a null value will cause an exception prior to query execution).
It is now possible to compile a schema with introspection disabled; this may be useful in production in some cases (though it prevents tools such as GraphiQL from operating).
selections-tree has changed; the value for a key is now a vector of nodes
(each possibly nil) rather than just a single node; this is to account for
the fact that a selection set may reference the same field, using different
aliases (and different arguments and sub-selections).
The built-in scalar types have been tightened up to more closely match the
spec; this means that some previously allowed input values (in a request)
or raw values (as provided by field resolvers) may now generate an error; for
example, previously, the Int scalar could parse a string value into an integer.
Remember it is possible to override built-in scalar types; if you
have clients that provide unsupported data (such as strings for Int fields),
you can provide an override of any built-in scalar to be more forgiving.
Added a schema compile option, :promote-nils-to-empty-list?, which converts
nils resolved from list fields back into empty lists (use only if you
have existing clients that break when they see those nils).
The com.walmartlabs.schema/coercion-failure function has been deprecated,
scalar parse and serialize functions can simply throw an exception rather
than invoke coercion-failure.
This release, regrettably, has some backwards incompatible changes (notice the 0. at the front
of the version number).
The necessary changes to existing applications are expected to be minor and localized.
Previous releases of the Schema Definition Language parser
wrapped the entire document with { and }.
This is not correct, and such documents are not valid SDL.
This release fixes that, but it means that any existing SDL documents will not parse correctly until the outermost curly braces are removed.
This release revamps how custom scalars are implemented. These changes make scalars more flexible, allowing for use cases that were previously not possible.
- The :parse and :serialize callbacks for scalars are no longer clojure.spec conformers, but are simple functions
- The :parse callback may now be passed non-strings, such as numbers or even maps
- The callbacks should not throw an exception, but should invoke
com.walmartlabs.lacinia.schema/coercion-failure. - Callbacks may also return nil to indicate a coercion failure
Schemas that use custom scalars will not compile until the scalars are updated (you'll see a clojure.spec validation exception).
Limited support for custom directives.
This release replaces the dependency on org.flatland/ordered with vendored copies of the code in an internal namespace. This is to enable compatibility with JDK 11.
Previously, there were places where a field resolver might return nil for a nullable list, and the nil was converted to an empty list. That no longer happens, the nil stays nil.
Added new resolver result modifiers, com.walmartlabs.lacinia.resolve/with-extensions
and with-warning.
A field resolver that returns a list of values may now wrap the individual
items in the list with com.walmartlabs.lacinia.resolve/with-context
(or with-error).
Changes have started to bring Lacinia into compliance with the June 2018 version of the GraphQL specification.
Lacinia now supports block strings (via """) in query and schema documents.
In addition, descriptions are now supported inside schema documents; a string (or block string) before an element in the schema becomes the documentation for that element.
The error maps inside the :error key are now structured according to the June 2018 spec;
the top level keys are :message, :locations, :path, and
:extensions (which contains any other keys in the error map supplied
by the field resolver).
The behavior of the :scalars option to com.walmartlabs.lacina.parser.schema/parse-schema
has changed slightly; the values provided are now merged with any scalar
data defined in the schema document.
Previously, the supplied value overwrote what was parsed.
Removed a potential race condition related to asynchronous field resolvers.
A change to how GraphQL schema documentation is attached.
Previously, arguments were refered to as :MyType.my_field/arg_name
but with this release, we've changed it to :MyType/my_field.arg_name.
It is now possible, when parsing a schema from SDL via
com.walmartlabs.lacinia.parser.schema/parse-schema, to
attach descriptions to interfaces, enums, scalars, and unions.
Previously, only objects and input objects could have descriptions attached.
New function com.walmartlabs.lacinia.util/inject-resolvers is an alternate way
to attach resolvers to a schema.
It is now possible to combine external documentation, from a Markdown file,
into an EDN schema.
See com.walmartlabs.lacinia.parser.docs/parse-docs and
Closed Issues
com.walmartlabs.lacinia.util/inject-descriptions.
Lacinia now supports the :roots key in the input schema, which makes
it possible to define query, mutation, or subscription operations
in terms of the fields of an explicitly named object in the schema.
This aligns Lacinia better with other implementations of GraphQL.
Lacinia is now based on Clojure 1.9, though it can also be used with Clojure 1.8.
Added the com.walmartlabs.lacinia.parser/summarize-query function,
which is used to summarize a query without distractions such as
aliases and field arguments. This is used to group similar
queries together when doing performance analysis.
Query parsing logic has been rewritten entirely, for performance and maintenance reasons. As a side effect, location information for query errors is more accurate.
Enum validation has changed: field resolvers may now return a keyword, symbol, or string. Internally, the value is converted to a keyword before being added to the response map.
However, field resolvers that return an invalid value for an enum field results in a thrown exception: previously, this was handled as a field error.
It is now possible to mark fields (including operations) and enum values as deprecated.
Compiled schemas now print and pretty-print as #CompiledSchema<>.
Added the FieldResolver protocol that allows a Clojure record, such as a Component, to act as a field resolver.
Field resolvers for enum types are now required to return a keyword, and that keyword must match one of the values defined for the enum. Previously, Lacinia failed to perform any checks in this case, which could result in invalid data present in the result map.
Added com.walmartlabs.lacina.resolve/wrap-resolver-result which makes it easier
to wrap an existing resolver function, but safely manipulate the resolved
value.
Fixes a bug that prevented operation names from working when a query defined only a single operation.
Previously, the reserved words 'query', 'mutation', and 'subscription' could not be used as the name of an operation, variable, field, etc. The grammar and parser have been changed to allow this.
Lacinia has a new API for parsing a GraphQL schema as an alternative to using Lacinia's EDN format.
Simplified a clojure.spec to prevent a potential runtime error
Could not locate clojure/test/check/generators__init.class or clojure/test/check/generators.clj on classpath.
This would occur when the :default-field-resolver option was specified, and org.clojure/test.check was
not on the classpath (it is a side-effect of having com.walmartlabs.lacina/compile
be always instrumented).
A number of small optimizations have been made, shaving a few milliseconds off selections on very large lists.
Object fields and field arguments may now inherit their description from corresponding fields and field arguments of an implemented interface.
There is now a mechanism to allow a ResolverResult callback to be invoked in a application-provided executor or thread pool.
Lacinia now includes support for GraphQL subscriptions.
Lacinia no longer catches and reports exceptions inside field resolvers.
It is now possible for a field resolver to modify the application context passed to all nested field resolvers (at any depth).
The :decorator option to com.walmartlabs.lacinia.schema/compile has been
removed. This is a feature, added in 0.17.0, that can be better implemented
in application code.
The callback provided to the
com.walmartlabs.lacinia.resolve/on-deliver! protocol method has
changed to only accept a single value.
Previously, the callback received a resolved value and an nilable error map.
This method is not intended for use in application code.
The com.walmartlabs.lacinia.schema/compile function is now always instrumented.
This means that non-conforming schemas will fail with a spec verification exception.
com.walmartlabs.lacinia.schema/tag-with-type now uses metadata in the majority of cases
(as it did in 0.16.0), resorting to a wrapper type only when
the value is a Java object that doesn't support metadata.
Queries with repeated identical fields (same alias and arguments) will now be merged together along with their subselections.
Fixed Selections API functions throwing a NullPointerException on Introspective meta fields.
Upgraded to clojure-future-spec 1.9.0-alpha17.
Lacinia now better implements the specification, in terms of parsing and serializing scalars.
The default mapping from field name to field resolver has simplified;
it is now a direct mapping, without converting underscores to dashes.
The old behavior is still available via an option to
com.walmartlabs.lacinia.schema/compile.
The function com.walmartlabs.lacinia.schema/tag-with-type has changed; it
now returns a special wrapper value (rather than the same value with
different metadata). This is to allow resolved values that do not
support metadata, such as Java objects.
The related function com.walmartlabs.lacinia.schema/type-tag has been removed.
Please update your applications carefully.
compile now has a new option, :decorator.
The decorator is a callback applied to all non-default field resolvers.
The primary use case is to adapt the return value of a field resolver,
for example, from a core.async channel to a Lacinia ResolverResult.
New function: com.walmartlabs.lacinia.parser/operations: extracts
from a parsed query the type (mutation or query) and the set of
operations.
Several new experimental functions were added to com.walmartlabs.lacinia.executor to
expose details about the selections tree; these functions can be invoked
from a field resolver to preview what fields will be selected below
the field.
The function com.walmartlabs.lacinia.schema/as-conformer is now public.
New function com.walmartlabs.lacinia/execute-parsed-query-async.
Lacinia can now, optionally, collect timing information about
field resolver functions. This information is returned in the
:extensions :timings key of the response.
Field resolvers can now operate synchronously or asynchronously.
This release fleshes out the Lacinia type system to be fully compliant with the
GraphQL type system.
Previously, there were significant limitations when combining list and non-null modifiers on types.
The internal representation of enum values has changed from String to Keyword. You will now see a Keyword, not a String, supplied as the value of an enum-typed argument or variable. You may need to make small changes to your field resolvers.
This release adds some very small performance improvements.
Field resolver functions may now return sets (where the schema type is a list). Previously this generated a runtime error.
There is a change to the signature of the
com.walmartlabs.lacinia.executor/execute-query function
that will not affect the majority of users.
We have removed an unused dependency on org.clojure/tools.macro.
And, of course, smaller fixes and improvements to the documentation.
Lucky 13 is our first publicly available version of Lacinia. It is still alpha and still subject to change, however.