Publishing: Gitlab support

Add support for publishing [Helm charts in the Gitlab Package
Registry](https://docs.gitlab.com/ee/user/packages/helm_repository/#helm-charts-in-the-package-registry).

Author: iconoeugen

docs/publishing-charts.adoc

@@ -6,7 +6,9 @@ The `helm-publish` plugin allows you to publish your charts to remote repositori
 ====
 There is currently no "official" API to publish Helm charts; Helm defines only how charts should be
 served from a repository. The plugin directly supports several types of popular repository servers, including
-https://chartmuseum.com/[ChartMuseum], https://jfrog.com/artifactory/[Artifactory] and https://goharbor.io/[Harbor].
+https://chartmuseum.com/[ChartMuseum], https://jfrog.com/artifactory/[Artifactory],
+https://goharbor.io/[Harbor], https://blog.sonatype.com/nexus-as-a-container-registry[Nexus] and
+https://docs.gitlab.com/ce/user/packages/container_registry/[Gitlab].
 
 For other repository types that are not directly supported, you could try using the `custom` repository type,
 or consider creating a PR to add support for it.
@@ -127,6 +129,8 @@ The following repository types are supported:
 - `artifactory`
 - `chartMuseum`
 - `harbor`
+- `nexus`
+- `gitlab`
 - `custom`
 
 
@@ -285,6 +289,43 @@ helm {
 TIP: Nexus API
 https://help.sonatype.com/repomanager3/rest-and-integration-api/components-api#ComponentsAPI-UploadComponent[documentation].
 
+=== Gitlab Repositories
+
+The plugin provides direct support for Gitlab repositories. The Gitlab API `url` and the `projectId` must be set in the
+repository configuration block.
+
+[source,groovy,role="primary"]
+.Groovy
+----
+helm {
+    publishing {
+        repositories {
+            gitlab {
+                url = uri('https://gitlab.example.com/api/v4')
+                projectId = 1234
+            }
+        }
+    }
+}
+----
+
+[source,kotlin,role="secondary"]
+.Kotlin
+----
+helm {
+    publishing {
+        repositories {
+            gitlab {
+                url.set(uri("https://gitlab.example.com/api/v4"))
+                projectName.set(1234)
+            }
+        }
+    }
+}
+----
+TIP: Helm charts in the Gitlab Package Registry
+https://docs.gitlab.com/ee/user/packages/helm_repository/#helm-charts-in-the-package-registry[documentation].
+
 === Custom Repositories
 
 If your target repository is not directly supported but involves some sort of HTTP upload, you can try the `custom`

helm-publish-plugin/src/main/kotlin/org/unbrokendome/gradle/plugins/helm/publishing/dsl/GitlabHelmPublishingRepository.kt

@@ -0,0 +1,78 @@
+package org.unbrokendome.gradle.plugins.helm.publishing.dsl
+
+import okhttp3.MultipartBody
+import okhttp3.RequestBody
+import okhttp3.RequestBody.Companion.asRequestBody
+import org.gradle.api.model.ObjectFactory
+import org.gradle.api.provider.Property
+import org.unbrokendome.gradle.plugins.helm.dsl.credentials.internal.SerializableCredentials
+import org.unbrokendome.gradle.plugins.helm.dsl.credentials.internal.toSerializable
+import org.unbrokendome.gradle.plugins.helm.publishing.publishers.AbstractHttpHelmChartPublisher
+import org.unbrokendome.gradle.plugins.helm.publishing.publishers.HelmChartPublisher
+import org.unbrokendome.gradle.plugins.helm.publishing.publishers.PublisherParams
+import org.unbrokendome.gradle.plugins.helm.publishing.util.toMultipartBody
+import org.unbrokendome.gradle.pluginutils.property
+import java.io.File
+import java.net.URI
+import javax.inject.Inject
+
+
+interface GitlabHelmPublishingRepository : HelmPublishingRepository {
+    /**
+     * The ID of the Gitlab project.
+     */
+    val projectId: Property<Int>
+}
+
+
+private open class DefaultGitlabHelmPublishingRepository @Inject constructor(
+    name: String,
+    objects: ObjectFactory
+) : AbstractHelmPublishingRepository(objects, name), GitlabHelmPublishingRepository {
+
+    override val projectId: Property<Int> =
+        objects.property()
+
+    override val publisherParams: PublisherParams
+        get() = GitlabPublisherParams(
+            url = requireNotNull(url.orNull) { "url is required for Gitlab publishing repository" },
+            credentials = configuredCredentials.orNull?.toSerializable(),
+            projectId = requireNotNull(projectId.orNull) { "projectId is required for Gitlab publishing repository" }
+        )
+
+
+    private class GitlabPublisherParams(
+        private val url: URI,
+        private val credentials: SerializableCredentials?,
+        private var projectId: Int
+    ) : PublisherParams {
+
+        override fun createPublisher(): HelmChartPublisher =
+            GitlabPublisher(url, credentials, projectId)
+    }
+
+
+    private class GitlabPublisher(
+        url: URI,
+        credentials: SerializableCredentials?,
+        private val projectId: Int
+    ) : AbstractHttpHelmChartPublisher(url, credentials) {
+
+        override val uploadMethod: String
+            get() = "POST"
+
+        override fun uploadPath(chartName: String, chartVersion: String): String =
+            "/projects/$projectId/packages/helm/api/stable/charts"
+
+        override fun requestBody(chartFile: File): RequestBody =
+            MultipartBody.Builder().run {
+                setType(MultipartBody.FORM)
+                addFormDataPart("chart", chartFile.name, chartFile.asRequestBody(MEDIA_TYPE_GZIP))
+                build()
+            }
+    }
+}
+
+
+internal fun ObjectFactory.newGitlabHelmPublishingRepository(name: String): GitlabHelmPublishingRepository =
+    newInstance(DefaultGitlabHelmPublishingRepository::class.java, name)

helm-publish-plugin/src/main/kotlin/org/unbrokendome/gradle/plugins/helm/publishing/dsl/HelmPublishingRepositoryContainer.kt

@@ -68,6 +68,19 @@ interface HelmPublishingRepositoryContainer : PolymorphicDomainObjectContainer<H
         configuration: Action<NexusHelmPublishingRepository>
     ): NexusHelmPublishingRepository =
         nexus("default", configuration)
+
+    @JvmDefault
+    fun gitlab(
+        name: String,
+        configuration: Action<GitlabHelmPublishingRepository>
+    ): GitlabHelmPublishingRepository =
+        create(name, GitlabHelmPublishingRepository::class.java, configuration)
+
+    @JvmDefault
+    fun gitlab(
+        configuration: Action<GitlabHelmPublishingRepository>
+    ): GitlabHelmPublishingRepository =
+        gitlab("default", configuration)
 }
 
 
@@ -96,6 +109,9 @@ private open class DefaultHelmPublishingRepositoryContainer
         registerFactory(NexusHelmPublishingRepository::class.java) { name ->
             objects.newNexusHelmPublishingRepository(name)
         }
+        registerFactory(GitlabHelmPublishingRepository::class.java) { name ->
+            objects.newGitlabHelmPublishingRepository(name)
+        }
 
         // Default type is "custom"
         registerDefaultFactory { name ->