feat(server): serve maven-metadata.xml (#1360)

Part of #1318.

Author: krzema12

jit-binding-server/src/main/kotlin/io/github/typesafegithub/workflows/jitbindingserver/Main.kt

@@ -5,6 +5,7 @@ import io.github.typesafegithub.workflows.actionbindinggenerator.domain.ActionCo
 import io.github.typesafegithub.workflows.mavenbinding.Artifact
 import io.github.typesafegithub.workflows.mavenbinding.JarArtifact
 import io.github.typesafegithub.workflows.mavenbinding.TextArtifact
+import io.github.typesafegithub.workflows.mavenbinding.buildPackageArtifacts
 import io.github.typesafegithub.workflows.mavenbinding.buildVersionArtifacts
 import io.ktor.http.ContentType
 import io.ktor.http.HttpStatusCode
@@ -81,6 +82,29 @@ fun main() {
                 }
             }
 
+            route("/binding/{owner}/{name}/{file}") {
+                get {
+                    val owner = call.parameters["owner"]!!
+                    val name = call.parameters["name"]!!
+                    val file = call.parameters["file"]!!
+                    val actionCoords =
+                        ActionCoords(
+                            owner = owner,
+                            name = name,
+                            version = "irrelevant",
+                        )
+                    val bindingArtifacts = actionCoords.buildPackageArtifacts(githubToken = System.getenv("GITHUB_TOKEN"))
+                    if (file in bindingArtifacts) {
+                        when (val artifact = bindingArtifacts[file]) {
+                            is String -> call.respondText(artifact)
+                            else -> call.respondText(text = "Not found", status = HttpStatusCode.NotFound)
+                        }
+                    } else {
+                        call.respondText(text = "Not found", status = HttpStatusCode.NotFound)
+                    }
+                }
+            }
+
             get("/status") {
                 call.respondText("OK")
             }

maven-binding-builder/build.gradle.kts

@@ -1,9 +1,16 @@
 plugins {
     buildsrc.convention.`kotlin-jvm`
+    kotlin("plugin.serialization")
 }
 
 dependencies {
     implementation("org.jetbrains.kotlin:kotlin-compiler")
     api(projects.actionBindingGenerator)
+    implementation(platform("io.ktor:ktor-bom:2.3.10"))
+    implementation("io.ktor:ktor-client-core")
+    implementation("io.ktor:ktor-client-cio")
+    implementation("io.ktor:ktor-client-content-negotiation")
+    implementation("io.ktor:ktor-serialization-kotlinx-json")
+
     runtimeOnly(projects.githubWorkflowsKt)
 }

maven-binding-builder/src/main/kotlin/io/github/typesafegithub/workflows/mavenbinding/MavenMetadataBuilding.kt

@@ -0,0 +1,91 @@
+package io.github.typesafegithub.workflows.mavenbinding
+
+import io.ktor.client.HttpClient
+import io.ktor.client.call.body
+import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.client.request.bearerAuth
+import io.ktor.client.request.get
+import io.ktor.serialization.kotlinx.json.json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+import java.time.Instant
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+
+internal suspend fun buildMavenMetadataFile(
+    owner: String,
+    name: String,
+    githubToken: String,
+): String {
+    val lastUpdated =
+        DateTimeFormatter.ofPattern("yyyyMMddHHmmss")
+            .withZone(ZoneId.systemDefault())
+            .format(Instant.now())
+    val availableMajorVersions =
+        fetchAvailableVersions(owner = owner, name = name, githubToken = githubToken)
+            .filter { !it.contains(".") }
+    val newest = availableMajorVersions.maxBy { it.removePrefix("v") }
+    return """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <metadata>
+          <groupId>$owner</groupId>
+          <artifactId>$name</artifactId>
+          <versioning>
+            <latest>$newest</latest>
+            <release>$newest</release>
+            <versions>
+${availableMajorVersions.joinToString(separator = "\n") {
+        "              <version>$it</version>"
+    }}
+            </versions>
+            <lastUpdated>$lastUpdated</lastUpdated>
+          </versioning>
+        </metadata>
+        """.trimIndent()
+}
+
+private suspend fun fetchAvailableVersions(
+    owner: String,
+    name: String,
+    githubToken: String,
+): List<String> =
+    listOf(
+        apiTagsUrl(owner = owner, name = name),
+        apiBranchesUrl(owner = owner, name = name),
+    ).flatMap { url -> fetchGithubRefs(url, githubToken) }
+        .map { it.ref.substringAfterLast("/") }
+
+private suspend fun fetchGithubRefs(
+    url: String,
+    githubToken: String,
+): List<GithubRef> =
+    httpClient.get(urlString = url) {
+        bearerAuth(githubToken)
+    }.body()
+
+private val httpClient by lazy {
+    HttpClient {
+        install(ContentNegotiation) {
+            json(
+                Json {
+                    ignoreUnknownKeys = true
+                },
+            )
+        }
+    }
+}
+
+private fun apiTagsUrl(
+    owner: String,
+    name: String,
+): String = "https://api.github.com/repos/$owner/$name/git/matching-refs/tags/v"
+
+private fun apiBranchesUrl(
+    owner: String,
+    name: String,
+): String = "https://api.github.com/repos/$owner/$name/git/matching-refs/heads/v"
+
+@Serializable
+data class GithubRef(
+    val ref: String,
+)

maven-binding-builder/src/main/kotlin/io/github/typesafegithub/workflows/mavenbinding/PackageArtifactsBuilding.kt

@@ -0,0 +1,10 @@
+package io.github.typesafegithub.workflows.mavenbinding
+
+import io.github.typesafegithub.workflows.actionbindinggenerator.domain.ActionCoords
+
+suspend fun ActionCoords.buildPackageArtifacts(githubToken: String): Map<String, String> {
+    val mavenMetadata = buildMavenMetadataFile(owner = owner, name = name, githubToken = githubToken)
+    return mapOf(
+        "maven-metadata.xml" to mavenMetadata,
+    )
+}