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Version: 4.x.x

Gradle Plugin Tasks

GraphQL Kotlin Gradle Plugin provides functionality to generate a lightweight GraphQL HTTP client and generate GraphQL schema directly from your source code.

info

This plugin is dependent on Kotlin compiler plugin as it generates Kotlin source code that needs to be compiled.

Usage​

graphql-kotlin-gradle-plugin is published on Gradle Plugin Portal. In order to execute any of the provided tasks you need to first apply the plugin on your project.

Using plugins DSL syntax

plugins {
    id("com.expediagroup.graphql") version $graphQLKotlinVersion
}

Or by using legacy plugin application

buildscript {
  repositories {
    maven {
      url = uri("https://plugins.gradle.org/m2/")
    }
  }
  dependencies {
    classpath("com.expediagroup:graphql-kotlin-gradle-plugin:$graphQLKotlinVersion")
  }
}

apply(plugin = "com.expediagroup.graphql")

Extension​

GraphQL Kotlin Gradle Plugin uses an extension on the project named graphql of type GraphQLPluginExtension. This extension can be used to configure global options instead of explicitly configuring individual tasks. Once extension is configured, it will automatically download SDL/run introspection to generate GraphQL schema and subsequently generate all GraphQL clients. GraphQL Extension should be used by default, except for cases where you need to only run individual tasks.

// build.gradle.kts
import com.expediagroup.graphql.plugin.gradle.config.GraphQLScalar
import com.expediagroup.graphql.plugin.gradle.config.GraphQLSerializer
import com.expediagroup.graphql.plugin.gradle.graphql

graphql {
  client {
    // Boolean flag indicating whether or not selection of deprecated fields is allowed.
    allowDeprecatedFields = false
    // List of custom GraphQL scalar to converter mapping containing information about corresponding Java type and converter that should be used to serialize/deserialize values.
    customScalars = listOf(GraphQLScalar("UUID", "java.util.UUID", "com.example.UUIDScalarConverter"))
    // GraphQL server endpoint that will be used to for running introspection queries. Alternatively you can download schema directly from `sdlEndpoint`.
    endpoint = "http://localhost:8080/graphql"
    // Optional HTTP headers to be specified on an introspection query or SDL request.
    headers = mapOf("X-Custom-Header" to "Custom-Header-Value")
    // Target package name to be used for generated classes.
    packageName = "com.example.generated"
    // Custom directory containing query files, defaults to src/main/resources
    queryFileDirectory = "${project.projectDir}/src/main/resources/queries"
    // Optional list of query files to be processed, takes precedence over queryFileDirectory
    queryFiles = listOf(file("${project.projectDir}/src/main/resources/queries/MyQuery.graphql"))
    // JSON serializer that will be used to generate the data classes.
    serializer = GraphQLSerializer.JACKSON
    // GraphQL server SDL endpoint that will be used to download schema. Alternatively you can run introspection query against `endpoint`.
    sdlEndpoint = "http://localhost:8080/sdl"
    // Timeout configuration for introspection query/downloading SDL
    timeout {
        // Connect timeout in milliseconds
        connect = 5_000
        // Read timeout in milliseconds
        read = 15_000
    }
  }
  schema {
    // List of supported packages that can contain GraphQL schema type definitions
    packages = listOf("com.example")
  }
}

Tasks​

By default, graphql-kotlin-gradle-plugin lazily registers all its tasks which means that while they are known to the build, they are not created nor executed until something in the build needs the instantiated object (e.g. adding explicit dependency on those tasks or explicitly creating them). Configuring plugin through the graphql extension will automatically create all the corresponding tasks.

All graphql-kotlin-gradle-plugin tasks are grouped together under GraphQL task group and their names are prefixed with graphql. You can find detailed information about GraphQL kotlin tasks by running Gradle help --task <taskName> task.

$ gradle --tasks

GraphQL tasks
-------------
graphqlDownloadSDL - Download schema in SDL format from target endpoint.
graphqlGenerateClient - Generate HTTP client from the specified GraphQL queries.
graphqlGenerateSDL - Generate GraphQL schema in SDL format.
graphqlGenerateTestClient - Generate HTTP test client from the specified GraphQL queries.
graphqlIntrospectSchema - Run introspection query against target GraphQL endpoint and save schema locally.--&gt;

graphqlDownloadSDL​

Task that attempts to download GraphQL schema in SDL format from the specified endpoint and saves the underlying schema file as schema.graphql under build directory. In general, this task provides limited functionality by itself and could be used as an alternative to graphqlIntrospectSchema to generate input for the subsequent graphqlGenerateClient task.

Properties

PropertyTypeRequiredDescription
endpointStringyesTarget GraphQL server SDL endpoint that will be used to download schema.
Command line property is: endpoint.
headersMap<String, Any>Optional HTTP headers to be specified on a SDL request.
outputFileFileTarget GraphQL schema file to be generated.
Default value is: ${project.buildDir}/schema.graphql
timeoutConfigTimeoutConfigTimeout configuration (in milliseconds) to download schema from SDL endpoint before we cancel the request.
Default value are:
connect timeout = 5_000
read timeout = 15_000.

graphqlGenerateClient​

Task that generates GraphQL Kotlin client and corresponding data classes based on the provided GraphQL queries that are evaluated against target Graphql schema. Individual clients with their specific data models are generated for each query file and are placed under specified packageName. When this task is added to the project, either through explicit configuration or through the graphql extension, it will automatically configure itself as a dependency of a compileKotlin task and resulting generated code will be automatically added to the project main source set.

Properties

PropertyTypeRequiredDescription
allowDeprecatedFieldsBooleanBoolean flag indicating whether selection of deprecated fields is allowed or not.
Default value is: false.
Command line property is: allowDeprecatedFields.
customScalarsList<GraphQLScalar>List of custom GraphQL scalar to converter mappings containing information about corresponding Java type and converter that should be used to serialize/deserialize values.
packageNameStringyesTarget package name for generated code.
Command line property is: packageName.
queryFilesFileCollectionList of query files to be processed. Instead of a list of files to be processed you can specify queryFileDirectory directory instead. If this property is specified it will take precedence over the corresponding directory property.
queryFileDirectoryStringDirectory file containing GraphQL queries. Instead of specifying a directory you can also specify list of query file by using queryFiles property instead.
Default value is: src/main/resources.
Command line property is: queryFileDirectory.
serializerGraphQLSerializerJSON serializer that will be used to generate the data classes.
Default value is: GraphQLSerializer.JACKSON.
schemaFileFileschemaFileName or schemaFile has to be providedGraphQL schema file that will be used to generate client code.
schemaFileNameStringschemaFileName or schemaFile has to be providedPath to GraphQL schema file that will be used to generate client code.
Command line property is: schemaFileName.

By default, this task will generate Jackson compatible data models. See client serialization documentation for details on how to update this process to use kotlinx.serialization instead.

graphqlGenerateSDL​

Task that generates GraphQL schema in SDL format from your source code using reflections. Utilizes graphql-kotlin-schema-generator to generate the schema from classes implementing graphql-kotlin-server marker Query, Mutation and Subscription interfaces. In order to limit the amount of packages to scan, this task requires users to provide a list of packages that can contain GraphQL types.

Properties

PropertyTypeRequiredDescription
packagesList<String>yesList of supported packages that can be scanned to generate SDL.
schemaFileFileTarget GraphQL schema file to be generated.
Default value is: ${project.buildDir}/schema.graphql

By default, this task will attempt to generate the schema using NoopSchemaGeneratorHooks. If you need to customize your schema generation process, you will need to provide your custom instance of SchemaGeneratorHooksProvider service provider. Service provider can be provided as part of your project, included in one of your project dependencies or through explicitly provided artifact to the graphqlSDL configuration.

dependencies {
    graphqlSDL("com.expediagroup:graphql-kotlin-federated-hooks-provider:$graphQLKotlinVersion")
}

graphqlGenerateTestClient​

Task that generates GraphQL Kotlin test client and corresponding data classes based on the provided GraphQL queries that are evaluated against target Graphql schema. Individual test clients with their specific data models are generated for each query file and are placed under specified packageName. When this task is added to the project it will automatically configure itself as a dependency of a compileTestKotlin task and resulting generated code will be automatically added to the project test source set.

Properties

PropertyTypeRequiredDescription
allowDeprecatedFieldsBooleanBoolean flag indicating whether selection of deprecated fields is allowed or not.
Default value is: false.
Command line property is: allowDeprecatedFields.
customScalarsList<GraphQLScalar>List of custom GraphQL scalar to converter mappings containing information about corresponding Java type and converter that should be used to serialize/deserialize values.
packageNameStringyesTarget package name for generated code.
Command line property is: packageName.
queryFilesFileCollectionList of query files to be processed. Instead of a list of files to be processed you can specify queryFileDirectory directory instead. If this property is specified it will take precedence over the corresponding directory property.
queryFileDirectoryStringDirectory file containing GraphQL queries. Instead of specifying a directory you can also specify list of query file by using queryFiles property instead.
Default value is: src/test/resources.
Command line property is: queryFileDirectory.
serializerGraphQLSerializerJSON serializer that will be used to generate the data classes.
Default value is: GraphQLSerializer.JACKSON.
schemaFileFileschemaFileName or schemaFile has to be providedGraphQL schema file that will be used to generate client code.
schemaFileNameStringschemaFileName or schemaFile has to be providedPath to GraphQL schema file that will be used to generate client code.
Command line property is: schemaFileName.

By default, this task will generate Jackson compatible data models. See client serialization documentation for details on how to update this process to use kotlinx.serialization instead.

graphqlIntrospectSchema​

Task that executes GraphQL introspection query against specified endpoint and saves the underlying schema file as schema.graphql under build directory. In general, this task provides limited functionality by itself and instead should be used to generate input for the subsequent graphqlGenerateClient task.

Properties

PropertyTypeRequiredDescription
endpointStringyesTarget GraphQL server endpoint that will be used to execute introspection queries.
Command line property is: endpoint.
headersMap<String, Any>Optional HTTP headers to be specified on an introspection query.
outputFileFileTarget GraphQL schema file to be generated.
Default value is: ${project.buildDir}/schema.graphql
timeoutConfigTimeoutConfigTimeout configuration (in milliseconds) to download schema from SDL endpoint before we cancel the request.
Default value are:
connect timeout = 5_000
read timeout = 15_000.