Make SchemaGenerator closeable (#643)

Extracting separate changes from #641 that cleans up the resources used when creating a new schema generator. Hopefully this will help with our unit test out of memory issues

Co-authored-by: Shane Myrick <[email protected]>

Author: smyrick

graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/federation/toFederatedSchema.kt

@@ -38,5 +38,7 @@ fun toFederatedSchema(
     subscriptions: List<TopLevelObject> = emptyList()
 ): GraphQLSchema {
     val generator = FederatedSchemaGenerator(config)
-    return generator.generateSchema(queries, mutations, subscriptions)
+    return generator.use {
+        it.generateSchema(queries, mutations, subscriptions)
+    }
 }

graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/SchemaGenerator.kt

@@ -28,6 +28,7 @@ import graphql.schema.GraphQLCodeRegistry
 import graphql.schema.GraphQLDirective
 import graphql.schema.GraphQLSchema
 import graphql.schema.GraphQLType
+import java.io.Closeable
 import java.util.concurrent.ConcurrentHashMap
 import kotlin.reflect.KClass
 import kotlin.reflect.KType
@@ -39,7 +40,7 @@ import kotlin.reflect.full.createType
  * This class maintains the state of the schema while generation is taking place. It is passed into the internal functions
  * so they can use the cache and add additional types and directives into the schema as they parse the Kotlin code.
  */
-open class SchemaGenerator(internal val config: SchemaGeneratorConfig) {
+open class SchemaGenerator(internal val config: SchemaGeneratorConfig) : Closeable {
 
     internal val additionalTypes = mutableSetOf<KType>()
     internal val classScanner = ClassScanner(config.supportedPackages)
@@ -100,4 +101,20 @@ open class SchemaGenerator(internal val config: SchemaGeneratorConfig) {
 
         return graphqlTypes.toSet()
     }
+
+    /**
+     * Clear the generator type cache, reflection scan, additional types,
+     * and the saved directives. You may want call this after you have
+     * called [generateSchema] and performed some other actions which is why
+     * we have a separate method to explicitly clear.
+     *
+     * If you use the built in [com.expediagroup.graphql.toSchema], we will handle
+     * clean up of resources for you.
+     */
+    override fun close() {
+        classScanner.close()
+        cache.clear()
+        additionalTypes.clear()
+        directives.clear()
+    }
 }

graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/state/ClassScanner.kt

@@ -19,10 +19,11 @@ package com.expediagroup.graphql.generator.state
 import io.github.classgraph.ClassGraph
 import io.github.classgraph.ClassInfo
 import io.github.classgraph.ClassInfoList
+import java.io.Closeable
 import kotlin.reflect.KClass
 import kotlin.reflect.jvm.jvmName
 
-internal class ClassScanner(supportedPackages: List<String>) {
+internal class ClassScanner(supportedPackages: List<String>) : Closeable {
 
     @Suppress("Detekt.SpreadOperator")
     private val scanResult = ClassGraph()
@@ -41,7 +42,7 @@ internal class ClassScanner(supportedPackages: List<String>) {
 
     fun getClassesWithAnnotation(annotation: KClass<*>) = scanResult.getClassesWithAnnotation(annotation.jvmName).map { it.loadClass().kotlin }
 
-    fun close() = scanResult.close()
+    override fun close() = scanResult.close()
 
     @Suppress("Detekt.SwallowedException")
     private fun getImplementingClasses(classInfo: ClassInfo) =

graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/toSchema.kt

@@ -38,5 +38,7 @@ fun toSchema(
     subscriptions: List<TopLevelObject> = emptyList()
 ): GraphQLSchema {
     val generator = SchemaGenerator(config)
-    return generator.generateSchema(queries, mutations, subscriptions)
+    return generator.use {
+        it.generateSchema(queries, mutations, subscriptions)
+    }
 }

graphql-kotlin-schema-generator/src/test/kotlin/com/expediagroup/graphql/testSchemaConfig.kt

@@ -22,7 +22,7 @@ import com.expediagroup.graphql.hooks.SchemaGeneratorHooks
 import io.mockk.every
 import io.mockk.spyk
 
-val defaultSupportedPackages = listOf("com.expediagroup")
+val defaultSupportedPackages = listOf("com.expediagroup.graphql")
 val testSchemaConfig = SchemaGeneratorConfig(defaultSupportedPackages)
 
 fun getTestSchemaConfigWithHooks(hooks: SchemaGeneratorHooks) = SchemaGeneratorConfig(defaultSupportedPackages, hooks = hooks)