feat(server): cache version artifacts if metadata is requested (#1908)

Fixes #1899

Author: Vampire

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

@@ -24,12 +24,17 @@ import io.ktor.server.routing.route
 import io.micrometer.core.instrument.Tag
 import io.micrometer.core.instrument.binder.cache.CaffeineCacheMetrics
 import io.micrometer.prometheusmetrics.PrometheusMeterRegistry
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
 import kotlin.time.Duration.Companion.hours
 
 private val logger = logger { }
 
 typealias ArtifactResult = Result<Map<String, Artifact>>
 
+private val prefetchScope = CoroutineScope(Dispatchers.IO)
+
 private val bindingsCache =
     Caffeine
         .newBuilder()
@@ -98,6 +103,12 @@ private fun Route.getArtifact(
     }
 }
 
+internal fun prefetchBindingArtifacts(coords: Collection<ActionCoords>) {
+    prefetchScope.launch {
+        bindingsCache.getAll(coords)
+    }
+}
+
 private suspend fun ApplicationCall.toBindingArtifacts(refresh: Boolean): Map<String, Artifact>? {
     val actionCoords = parameters.extractActionCoords(extractVersion = true)
 

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

@@ -28,7 +28,7 @@ private val metadataCache =
         .recordStats()
         .asLoadingCache<ActionCoords, MetadataResult> {
             runCatching {
-                it.buildPackageArtifacts(githubAuthToken = getGithubAuthToken())
+                it.buildPackageArtifacts(githubAuthToken = getGithubAuthToken(), ::prefetchBindingArtifacts)
             }
         }
 

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

@@ -18,13 +18,15 @@ internal suspend fun ActionCoords.buildMavenMetadataFile(
         name: String,
         githubAuthToken: String?,
     ) -> Either<String, List<Version>> = ::fetchAvailableVersions,
+    prefetchBindingArtifacts: (Collection<ActionCoords>) -> Unit = {},
 ): String? {
     val availableVersions =
         fetchAvailableVersions(owner, name, githubAuthToken)
             .getOrElse {
                 logger.error { it }
                 emptyList()
             }.filter { it.isMajorVersion() || (significantVersion < FULL) }
+    prefetchBindingArtifacts(availableVersions.map { copy(version = "$it") })
     val newest = availableVersions.maxOrNull() ?: return null
     val lastUpdated =
         DateTimeFormatter

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

@@ -2,8 +2,15 @@ package io.github.typesafegithub.workflows.mavenbinding
 
 import io.github.typesafegithub.workflows.actionbindinggenerator.domain.ActionCoords
 
-suspend fun ActionCoords.buildPackageArtifacts(githubAuthToken: String): Map<String, String> {
-    val mavenMetadata = buildMavenMetadataFile(githubAuthToken = githubAuthToken) ?: return emptyMap()
+suspend fun ActionCoords.buildPackageArtifacts(
+    githubAuthToken: String,
+    prefetchBindingArtifacts: (Collection<ActionCoords>) -> Unit,
+): Map<String, String> {
+    val mavenMetadata =
+        buildMavenMetadataFile(
+            githubAuthToken = githubAuthToken,
+            prefetchBindingArtifacts = prefetchBindingArtifacts,
+        ) ?: return emptyMap()
     return mapOf(
         "maven-metadata.xml" to mavenMetadata,
         "maven-metadata.xml.md5" to mavenMetadata.md5Checksum(),