[gradle] Enabling up-to-date checks and gradle caching for openapigenerator tasks (#6716)

appveyor.yml

@@ -15,14 +15,14 @@ install:
   # install gradle
   - ps: |
       Add-Type -AssemblyName System.IO.Compression.FileSystem
-      if (!(Test-Path -Path "C:\gradle" )) {
+      if (!(Test-Path -Path "C:\gradle\gradle-5.6.4" )) {
         (new-object System.Net.WebClient).DownloadFile(
-          'https://services.gradle.org/distributions/gradle-5.3.1-bin.zip',
+          'https://services.gradle.org/distributions/gradle-5.6.4-bin.zip',
           'C:\gradle-bin.zip'
         )
         [System.IO.Compression.ZipFile]::ExtractToDirectory("C:\gradle-bin.zip", "C:\gradle")
       }
-  - cmd: SET PATH=C:\maven\apache-maven-3.2.5\bin;C:\gradle\gradle-5.3.1\bin;%JAVA_HOME%\bin;%PATH%
+  - cmd: SET PATH=C:\maven\apache-maven-3.2.5\bin;C:\gradle\gradle-5.6.4\bin;%JAVA_HOME%\bin;%PATH%
   - cmd: SET MAVEN_OPTS=-Xmx4g
   - cmd: SET JAVA_OPTS=-Xmx4g
   - cmd: SET M2_HOME=C:\maven\apache-maven-3.2.5

modules/openapi-generator-gradle-plugin/README.adoc

@@ -61,6 +61,35 @@ task validateBadSpec(type: org.openapitools.generator.gradle.plugin.tasks.Valida
 task validateSpecs(dependsOn: ['validateGoodSpec', 'validateBadSpec'])
 ----
 
+[NOTE]
+====
+The tasks support Gradle Up-To-Date checking and Gradle Cache. Enable caching globally by setting `org.gradle.caching=true` in the `gradle.settings`
+file or by passing the command line property `--build-cache` when executing on the command line.
+
+Disable up-to-date checks and caching by setting the following property when using the extension:
+
+.Disable caching for extension
+[source,groovy]
+----
+tasks.withType(org.openapitools.generator.gradle.plugin.tasks.GenerateTask) {
+    outputs.upToDateWhen { false }
+    outputs.cacheIf { false }
+}
+----
+Disable up-to-date checks and caching for a custom task:
+
+.Disable caching for custom task
+[source,groovy]
+----
+task validateGoodSpec(type: org.openapitools.generator.gradle.plugin.tasks.ValidateTask){
+    outputs.upToDateWhen { false }
+    outputs.cacheIf { false }
+
+    inputSpec = "$rootDir/petstore-v3.0.yaml".toString()
+}
+----
+====
+
 == Plugin Setup
 
 //# RELEASE_VERSION

modules/openapi-generator-gradle-plugin/gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 #Thu Jan 30 22:14:34 EST 2020
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.2.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.4-all.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStorePath=wrapper/dists

modules/openapi-generator-gradle-plugin/samples/local-spec/README.md

@@ -1,18 +1,18 @@
 # Local Spec Sample
 
-This example assumes you have Gradle 4.7+ installed. No gradle wrapper is provided in samples.
+This example assumes you have Gradle 5.6.4+ installed. No gradle wrapper is provided in samples.
 
-First, publish the openapi-generator-gradle-plugin locally via `./gradlew assemble install` in the module directory.
+First, publish the openapi-generator-gradle-plugin locally via `./gradlew assemble publishToMavenLocal` in the module directory.
 
 Then, run the following tasks in this example directory.
 
 ```bash
-gradle openApiGenerate
+gradle openApiGenerate              # expected outcome: BUILD SCCESSFUL
-gradle openApiMeta
+gradle openApiMeta                  # expected outcome: BUILD SCCESSFUL
-gradle openApiValidate
+gradle openApiValidate              # expected outcome: BUILD FAILED 
-gradle buildGoSdk
+gradle buildGoSdk                   # expected outcome: BUILD SCCESSFUL
-gradle buildDotnetSdk
+gradle buildDotnetSdk               # expected outcome: BUILD SCCESSFUL
-gradle generateGoWithInvalidSpec
+gradle generateGoWithInvalidSpec    # expected outcome: BUILD FAILED 
 ```
 
 The samples can be tested against other versions of the plugin using the `openApiGeneratorVersion` property. For example:

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/OpenApiGeneratorPlugin.kt

@@ -55,9 +55,9 @@ class OpenApiGeneratorPlugin : Plugin<Project> {
             )
 
             val generators = extensions.create(
-                "openApiGenerators",
+                    "openApiGenerators",
-                OpenApiGeneratorGeneratorsExtension::class.java,
+                    OpenApiGeneratorGeneratorsExtension::class.java,
-                project
+                    project
             )
 
             generate.outputDir.set("$buildDir/generate-resources/main")

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/extensions/OpenApiGeneratorGenerateExtension.kt

@@ -317,7 +317,7 @@ open class OpenApiGeneratorGenerateExtension(project: Project) {
     }
 
     @Suppress("MemberVisibilityCanBePrivate")
-    fun applyDefaults(){
+    fun applyDefaults() {
         releaseNote.set("Minor update")
         modelNamePrefix.set("")
         modelNameSuffix.set("")

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/tasks/GenerateTask.kt

@@ -19,7 +19,14 @@ package org.openapitools.generator.gradle.plugin.tasks
 import org.gradle.api.DefaultTask
 import org.gradle.api.GradleException
 import org.gradle.api.provider.Property
+import org.gradle.api.tasks.CacheableTask
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputFile
 import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.Optional
+import org.gradle.api.tasks.OutputDirectory
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
 import org.gradle.api.tasks.TaskAction
 import org.gradle.api.tasks.options.Option
 import org.gradle.internal.logging.text.StyledTextOutput
@@ -32,7 +39,6 @@ import org.openapitools.codegen.DefaultGenerator
 import org.openapitools.codegen.config.CodegenConfigurator
 import org.openapitools.codegen.config.GlobalSettings
 
-
 /**
  * A task which generates the desired code.
  *
@@ -43,63 +49,73 @@ import org.openapitools.codegen.config.GlobalSettings
  * @author Jim Schubert
  */
 @Suppress("UnstableApiUsage")
+@CacheableTask
 open class GenerateTask : DefaultTask() {
 
     /**
      * The verbosity of generation
      */
-    @get:Internal
+    @Optional
+    @Input
     val verbose = project.objects.property<Boolean>()
 
     /**
      * Whether or not an input specification should be validated upon generation.
      */
-    @get:Internal
+    @Optional
+    @Input
     val validateSpec = project.objects.property<Boolean>()
 
     /**
      * The name of the generator which will handle codegen. (see "openApiGenerators" task)
      */
-    @get:Internal
+    @Optional
+    @Input
     val generatorName = project.objects.property<String>()
 
     /**
      * The output target directory into which code will be generated.
      */
-    @get:Internal
+    @Optional
+    @get:OutputDirectory
     val outputDir = project.objects.property<String>()
 
     @Suppress("unused")
     @get:Internal
     @set:Option(option = "input", description = "The input specification.")
+    @Input
     var input: String? = null
         set(value) {
             inputSpec.set(value)
         }
-    
+
     /**
      * The Open API 2.0/3.x specification location.
      */
-    @get:Internal
+    @get:InputFile
+    @PathSensitive(PathSensitivity.RELATIVE)
     val inputSpec = project.objects.property<String>()
 
     /**
      * The template directory holding a custom template.
      */
-    @get:Internal
+    @Optional
+    @Input
     val templateDir = project.objects.property<String?>()
 
     /**
      * Adds authorization headers when fetching the OpenAPI definitions remotely.
      * Pass in a URL-encoded string of name:header with a comma separating multiple values
      */
-    @get:Internal
+    @Optional
+    @Input
     val auth = project.objects.property<String>()
 
     /**
      * Sets specified global properties.
      */
-    @get:Internal
+    @Optional
+    @Input
     val globalProperties = project.objects.mapProperty<String, String>()
 
     /**
@@ -107,159 +123,185 @@ open class GenerateTask : DefaultTask() {
      * File content should be in a json format { "optionKey":"optionValue", "optionKey1":"optionValue1"...}
      * Supported options can be different for each language. Run config-help -g {generator name} command for language specific config options.
      */
-    @get:Internal
+    @Optional
+    @Input
     val configFile = project.objects.property<String>()
 
     /**
      * Specifies if the existing files should be overwritten during the generation.
      */
-    @get:Internal
+    @Optional
+    @Input
     val skipOverwrite = project.objects.property<Boolean?>()
 
     /**
      * Package for generated classes (where supported)
      */
-    @get:Internal
+    @Optional
+    @Input
     val packageName = project.objects.property<String>()
 
     /**
      * Package for generated api classes
      */
-    @get:Internal
+    @Optional
+    @Input
     val apiPackage = project.objects.property<String>()
 
     /**
      * Package for generated models
      */
-    @get:Internal
+    @Optional
+    @Input
     val modelPackage = project.objects.property<String>()
 
     /**
      * Prefix that will be prepended to all model names. Default is the empty string.
      */
-    @get:Internal
+    @Optional
+    @Input
     val modelNamePrefix = project.objects.property<String>()
 
     /**
      * Suffix that will be appended to all model names. Default is the empty string.
      */
-    @get:Internal
+    @Optional
+    @Input
     val modelNameSuffix = project.objects.property<String>()
 
     /**
      * Sets instantiation type mappings.
      */
-    @get:Internal
+    @Optional
+    @Input
     val instantiationTypes = project.objects.mapProperty<String, String>()
 
     /**
      * Sets mappings between OpenAPI spec types and generated code types.
      */
-    @get:Internal
+    @Optional
+    @Input
     val typeMappings = project.objects.mapProperty<String, String>()
 
     /**
      * Sets additional properties that can be referenced by the mustache templates in the format of name=value,name=value.
      * You can also have multiple occurrences of this option.
      */
-    @get:Internal
+    @Optional
+    @Input
     val additionalProperties = project.objects.mapProperty<String, String>()
 
     /**
      * Sets server variable for server URL template substitution, in the format of name=value,name=value.
      * You can also have multiple occurrences of this option.
      */
-    @get:Internal
+    @Optional
+    @Input
     val serverVariables = project.objects.mapProperty<String, String>()
 
     /**
      * Specifies additional language specific primitive types in the format of type1,type2,type3,type3. For example: String,boolean,Boolean,Double.
      */
-    @get:Internal
+    @Optional
+    @Input
     val languageSpecificPrimitives = project.objects.listProperty<String>()
 
     /**
      * Specifies mappings between a given class and the import that should be used for that class.
      */
-    @get:Internal
+    @Optional
+    @Input
     val importMappings = project.objects.mapProperty<String, String>()
 
     /**
      * Root package for generated code.
      */
-    @get:Internal
+    @Optional
+    @Input
     val invokerPackage = project.objects.property<String>()
 
     /**
      * GroupId in generated pom.xml/build.gradle or other build script. Language-specific conversions occur in non-jvm generators.
      */
-    @get:Internal
+    @Optional
+    @Input
     val groupId = project.objects.property<String>()
 
     /**
      * ArtifactId in generated pom.xml/build.gradle or other build script. Language-specific conversions occur in non-jvm generators.
      */
-    @get:Internal
+    @Optional
+    @Input
     val id = project.objects.property<String>()
 
     /**
      * Artifact version in generated pom.xml/build.gradle or other build script. Language-specific conversions occur in non-jvm generators.
      */
-    @get:Internal
+    @Optional
+    @Input
     val version = project.objects.property<String>()
 
     /**
      * Reference the library template (sub-template) of a generator.
      */
-    @get:Internal
+    @Optional
+    @Input
     val library = project.objects.property<String?>()
 
     /**
      * Git host, e.g. gitlab.com.
      */
-    @get:Internal
+    @Optional
+    @Input
     val gitHost = project.objects.property<String?>()
 
     /**
      * Git user ID, e.g. openapitools.
      */
-    @get:Internal
+    @Optional
+    @Input
     val gitUserId = project.objects.property<String?>()
 
     /**
      * Git repo ID, e.g. openapi-generator.
      */
-    @get:Internal
+    @Optional
+    @Input
     val gitRepoId = project.objects.property<String?>()
 
     /**
      * Release note, default to 'Minor update'.
      */
-    @get:Internal
+    @Optional
+    @Input
     val releaseNote = project.objects.property<String?>()
 
     /**
      * HTTP user agent, e.g. codegen_csharp_api_client, default to 'OpenAPI-Generator/{packageVersion}/{language}'
      */
-    @get:Internal
+    @Optional
+    @Input
     val httpUserAgent = project.objects.property<String?>()
 
     /**
      * Specifies how a reserved name should be escaped to.
      */
-    @get:Internal
+    @Optional
+    @Input
     val reservedWordsMappings = project.objects.mapProperty<String, String>()
 
     /**
      * Specifies an override location for the .openapi-generator-ignore file. Most useful on initial generation.
      */
-    @get:Internal
+    @Optional
+    @Input
     val ignoreFileOverride = project.objects.property<String?>()
 
     /**
      * Remove prefix of operationId, e.g. config_getId => getId
      */
-    @get:Internal
+    @Optional
+    @Input
     val removeOperationIdPrefix = project.objects.property<Boolean?>()
 
     /**
@@ -271,7 +313,8 @@ open class GenerateTask : DefaultTask() {
      *   in others being disabled. That is, OpenAPI Generator considers any one of these to define a subset of generation.
      *   For more control over generation of individual files, configure an ignore file and refer to it via [ignoreFileOverride].
      */
-    @get:Internal
+    @Optional
+    @Input
     val apiFilesConstrainedTo = project.objects.listProperty<String>()
 
     /**
@@ -281,7 +324,8 @@ open class GenerateTask : DefaultTask() {
      *   in others being disabled. That is, OpenAPI Generator considers any one of these to define a subset of generation.
      *   For more control over generation of individual files, configure an ignore file and refer to it via [ignoreFileOverride].
      */
-    @get:Internal
+    @Optional
+    @Input
     val modelFilesConstrainedTo = project.objects.listProperty<String>()
 
     /**
@@ -294,7 +338,8 @@ open class GenerateTask : DefaultTask() {
      *   in others being disabled. That is, OpenAPI Generator considers any one of these to define a subset of generation.
      *   For more control over generation of individual files, configure an ignore file and refer to it via [ignoreFileOverride].
      */
-    @get:Internal
+    @Optional
+    @Input
     val supportingFilesConstrainedTo = project.objects.listProperty<String>()
 
     /**
@@ -305,7 +350,8 @@ open class GenerateTask : DefaultTask() {
      * For more control over generation of individual files, configure an ignore file and
      * refer to it via [ignoreFileOverride].
      */
-    @get:Internal
+    @Optional
+    @Input
     val generateModelTests = project.objects.property<Boolean>()
 
     /**
@@ -316,7 +362,8 @@ open class GenerateTask : DefaultTask() {
      * For more control over generation of individual files, configure an ignore file and
      * refer to it via [ignoreFileOverride].
      */
-    @get:Internal
+    @Optional
+    @Input
     val generateModelDocumentation = project.objects.property<Boolean>()
 
     /**
@@ -327,7 +374,8 @@ open class GenerateTask : DefaultTask() {
      * For more control over generation of individual files, configure an ignore file and
      * refer to it via [ignoreFileOverride].
      */
-    @get:Internal
+    @Optional
+    @Input
     val generateApiTests = project.objects.property<Boolean>()
 
     /**
@@ -338,21 +386,23 @@ open class GenerateTask : DefaultTask() {
      * For more control over generation of individual files, configure an ignore file and
      * refer to it via [ignoreFileOverride].
      */
-    @get:Internal
+    @Optional
+    @Input
     val generateApiDocumentation = project.objects.property<Boolean>()
 
     /**
      * A special-case setting which configures some generators with XML support. In some cases,
      * this forces json OR xml, so the default here is false.
      */
-    @get:Internal
+    @Optional
+    @Input
     val withXml = project.objects.property<Boolean>()
 
-
     /**
      * To write all log messages (not just errors) to STDOUT
      */
-    @get:Internal
+    @Optional
+    @Input
     val logToStderr = project.objects.property<Boolean>()
 
     /**
@@ -361,13 +411,15 @@ open class GenerateTask : DefaultTask() {
      * LANG_POST_PROCESS_FILE (e.g. GO_POST_PROCESS_FILE, SCALA_POST_PROCESS_FILE). Please open an issue if your target
      * generator does not support this functionality.
      */
-    @get:Internal
+    @Optional
+    @Input
     val enablePostProcessFile = project.objects.property<Boolean>()
 
     /**
      * To skip spec validation. When true, we will skip the default behavior of validating a spec before generation.
      */
-    @get:Internal
+    @Optional
+    @Input
     val skipValidateSpec = project.objects.property<Boolean>()
 
     /**
@@ -375,19 +427,22 @@ open class GenerateTask : DefaultTask() {
      * definitions generated as top-level Array-of-items, List-of-items, Map-of-items definitions.
      * When true, A model representation either containing or extending the array,list,map (depending on specific generator implementation) will be generated.
      */
-    @get:Internal
+    @Optional
+    @Input
     val generateAliasAsModel = project.objects.property<Boolean>()
 
     /**
      * A dynamic map of options specific to a generator.
      */
-    @get:Internal
+    @Optional
+    @Input
     val configOptions = project.objects.mapProperty<String, String>()
 
     /**
      * Templating engine: "mustache" (default) or "handlebars" (beta)
      */
-    @get:Internal
+    @Optional
+    @Input
     val engine = project.objects.property<String?>()
 
     private fun <T : Any?> Property<T>.ifNotEmpty(block: Property<T>.(T) -> Unit) {

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/tasks/MetaTask.kt

@@ -19,15 +19,18 @@ package org.openapitools.generator.gradle.plugin.tasks
 import com.samskivert.mustache.Mustache
 import org.gradle.api.DefaultTask
 import org.gradle.api.GradleException
-import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.CacheableTask
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.OutputDirectory
 import org.gradle.api.tasks.TaskAction
 import org.gradle.internal.logging.text.StyledTextOutput
 import org.gradle.internal.logging.text.StyledTextOutputFactory
 import org.gradle.kotlin.dsl.property
-import org.openapitools.codegen.*
+import org.openapitools.codegen.CodegenConfig
-import org.openapitools.codegen.api.TemplatePathLocator
+import org.openapitools.codegen.CodegenConstants
+import org.openapitools.codegen.SupportingFile
+import org.openapitools.codegen.TemplateManager
 import org.openapitools.codegen.templating.CommonTemplateContentLocator
-import org.openapitools.codegen.templating.GeneratorTemplateContentLocator
 import org.openapitools.codegen.templating.MustacheEngineAdapter
 import org.openapitools.codegen.templating.TemplateManagerOptions
 import java.io.File
@@ -39,15 +42,16 @@ import java.nio.charset.Charset
  *
  * @author Jim Schubert
  */
+@CacheableTask
 open class MetaTask : DefaultTask() {
 
-    @get:Internal
+    @get:Input
     val generatorName = project.objects.property<String>()
 
-    @get:Internal
+    @get:Input
     val packageName = project.objects.property<String>()
 
-    @get:Internal
+    @get:OutputDirectory
     val outputFolder = project.objects.property<String>()
 
     @Suppress("unused")
@@ -92,9 +96,9 @@ open class MetaTask : DefaultTask() {
                 val outputFile = File(destinationFolder, it.destinationFilename)
 
                 val templateProcessor = TemplateManager(
-                    TemplateManagerOptions(false, false),
+                        TemplateManagerOptions(false, false),
-                    MustacheEngineAdapter(),
+                        MustacheEngineAdapter(),
-                    arrayOf(CommonTemplateContentLocator("codegen"))
+                        arrayOf(CommonTemplateContentLocator("codegen"))
                 )
 
                 val template = templateProcessor.getFullTemplateContents(it.templateFile)

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/tasks/ValidateTask.kt

@@ -23,7 +23,12 @@ import io.swagger.v3.parser.core.models.ParseOptions
 import org.gradle.api.DefaultTask
 import org.gradle.api.GradleException
 import org.gradle.api.logging.Logging
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputFile
 import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.Optional
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
 import org.gradle.api.tasks.TaskAction
 import org.gradle.api.tasks.options.Option
 import org.gradle.internal.logging.text.StyledTextOutput
@@ -49,10 +54,12 @@ import org.openapitools.codegen.validations.oas.RuleConfiguration
  * @author Jim Schubert
  */
 open class ValidateTask : DefaultTask() {
-    @get:Internal
+    @get:InputFile
+    @PathSensitive(PathSensitivity.RELATIVE)
     var inputSpec = project.objects.property<String>()
 
-    @get:Internal
+    @Optional
+    @Input
     var recommend = project.objects.property<Boolean?>()
 
     @Suppress("unused")
@@ -75,12 +82,11 @@ open class ValidateTask : DefaultTask() {
 
         val options = ParseOptions()
         options.isResolve = true
-        
+
         val result = OpenAPIParser().readLocation(spec, null, options)
         val messages = result.messages.toSet()
         val out = services.get(StyledTextOutputFactory::class.java).create("openapi")
 
-
         val ruleConfiguration = RuleConfiguration()
         ruleConfiguration.isEnableRecommendations = recommendations
 

modules/openapi-generator-gradle-plugin/src/test/kotlin/GenerateTaskDslTest.kt

@@ -7,7 +7,7 @@ import java.io.File
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 
-class GenerateTaskDslTest : TestBase()  {
+class GenerateTaskDslTest : TestBase() {
     override var temp: File = createTempDir(javaClass.simpleName)
 
     private val defaultBuildGradle = """
@@ -46,18 +46,18 @@ class GenerateTaskDslTest : TestBase()  {
         assertTrue(result.output.contains("Successfully generated code to"), "User friendly generate notice is missing.")
 
         listOf(
-            "build/kotlin/.openapi-generator-ignore",
+                "build/kotlin/.openapi-generator-ignore",
-            "build/kotlin/docs/PetsApi.md",
+                "build/kotlin/docs/PetsApi.md",
-            "build/kotlin/docs/Error.md",
+                "build/kotlin/docs/Error.md",
-            "build/kotlin/docs/Pet.md",
+                "build/kotlin/docs/Pet.md",
-            "build/kotlin/README.md",
+                "build/kotlin/README.md",
-            "build/kotlin/build.gradle",
+                "build/kotlin/build.gradle",
-            "build/kotlin/.openapi-generator/VERSION",
+                "build/kotlin/.openapi-generator/VERSION",
-            "build/kotlin/settings.gradle",
+                "build/kotlin/settings.gradle",
-            "build/kotlin/src/main/kotlin/org/openapitools/example/model/Pet.kt",
+                "build/kotlin/src/main/kotlin/org/openapitools/example/model/Pet.kt",
-            "build/kotlin/src/main/kotlin/org/openapitools/example/model/Error.kt",
+                "build/kotlin/src/main/kotlin/org/openapitools/example/model/Error.kt",
-            "build/kotlin/src/main/kotlin/org/openapitools/example/api/PetsApi.kt",
+                "build/kotlin/src/main/kotlin/org/openapitools/example/api/PetsApi.kt",
-            "build/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt"
+                "build/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt"
         ).map {
             val f = File(temp, it)
             assertTrue(f.exists() && f.isFile, "An expected file was not generated when invoking the generation.")
@@ -67,6 +67,61 @@ class GenerateTaskDslTest : TestBase()  {
                 "Expected a successful run, but found ${result.task(":openApiGenerate")?.outcome}")
     }
 
+    @Test
+    fun `openApiGenerate should used up-to-date instead of regenerate`() {
+        // Arrange
+        val projectFiles = mapOf(
+                "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0.yaml")
+        )
+        withProject(defaultBuildGradle, projectFiles)
+
+        // Act
+        val resultFirstRun = GradleRunner.create()
+                .withProjectDir(temp)
+                .withArguments("openApiGenerate")
+                .withPluginClasspath()
+                .build()
+        val resultSecondRun = GradleRunner.create()
+                .withProjectDir(temp)
+                .withArguments("openApiGenerate")
+                .withPluginClasspath()
+                .build()
+
+        // Assert
+        assertTrue(resultFirstRun.output.contains("Task ':openApiGenerate' is not up-to-date"), "First run should not be up-to-date")
+        assertTrue(resultSecondRun.output.contains("Task :openApiGenerate UP-TO-DATE"), "Task of second run should be up-to-date")
+    }
+
+    @Test
+    fun `openApiGenerate should use cache instead of regenerate`() {
+        // Arrange
+        val projectFiles = mapOf(
+                "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0.yaml")
+        )
+        withProject(defaultBuildGradle, projectFiles)
+
+        // Act
+        val resultFirstRun = GradleRunner.create()
+                .withProjectDir(temp)
+                .withArguments("openApiGenerate", "--build-cache")
+                .withPluginClasspath()
+                .build()
+
+        // delete the build directory from the last run
+        File(temp, "build/kotlin").deleteRecursively()
+
+        // re-run
+        val resultSecondRun = GradleRunner.create()
+                .withProjectDir(temp)
+                .withArguments("openApiGenerate", "--build-cache")
+                .withPluginClasspath()
+                .build()
+
+        // Assert
+        assertTrue(resultFirstRun.output.contains("Task ':openApiGenerate' is not up-to-date"), "First run should not be up-to-date")
+        assertTrue(resultSecondRun.output.contains("Task :openApiGenerate FROM-CACHE"), "Task of second run should be from cache")
+    }
+
     @Test
     fun `openApiValidate should fail on invalid spec`() {
         // Arrange
@@ -128,10 +183,10 @@ class GenerateTaskDslTest : TestBase()  {
     }
 
     @Test
-    fun `openapiGenerate should attempt to set handlebars when specified as engine`(){
+    fun `openapiGenerate should attempt to set handlebars when specified as engine`() {
         // Arrange
         val projectFiles = mapOf(
-            "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0.yaml")
+                "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0.yaml")
         )
 
         withProject("""
@@ -151,16 +206,16 @@ class GenerateTaskDslTest : TestBase()  {
 
         // Act
         val result = GradleRunner.create()
-            .withProjectDir(temp)
+                .withProjectDir(temp)
-            .withArguments("openApiGenerate", "--stacktrace")
+                .withArguments("openApiGenerate", "--stacktrace")
-            .withPluginClasspath()
+                .withPluginClasspath()
-            .buildAndFail()
+                .buildAndFail()
 
         // Assert
         // rather than write out full handlebars generator templates, we'll just test that the configurator has set handlebars as the engine.
         assertTrue(result.output.contains("HandlebarsException"), "Stack should expose an exception for missing templates.")
         assertTrue(result.output.contains("handlebars"), "Build should have attempted to use handlebars.")
         assertEquals(TaskOutcome.FAILED, result.task(":openApiGenerate")?.outcome,
-            "Expected a failed run, but found ${result.task(":openApiGenerate")?.outcome}")
+                "Expected a failed run, but found ${result.task(":openApiGenerate")?.outcome}")
     }
 }