Trying lower implementation cost of getting S3 bytes

build.sbt

@@ -6,8 +6,6 @@ name := "facia-api-client"
 
 description := "Scala client for The Guardian's Facia JSON API"
 
-ThisBuild / scalaVersion := "2.13.14"
-
 val sonatypeReleaseSettings = Seq(
   // releaseVersion := fromAggregatedAssessedCompatibilityWithLatestRelease().value,
   releaseCrossBuild := true, // true if you cross-build the project for multiple Scala versions
@@ -42,14 +40,8 @@ lazy val fapiClient_core = (project in file("fapi-client-core")).settings(
   artifactProducingSettings(supportScala3 = true)
 )
 
-lazy val fapiClient_s3_sdk_v2 = (project in file("fapi-s3-sdk-v2")).dependsOn(fapiClient_core).settings(
-  libraryDependencies += eTagCachingS3SdkV2,
-  artifactProducingSettings(supportScala3 = true)
-)
-
 lazy val root = (project in file(".")).aggregate(
     fapiClient_core,
-    fapiClient_s3_sdk_v2,
     faciaJson_play28,
     faciaJson_play29,
     faciaJson_play30,

facia-json/src/main/scala/com/gu/facia/client/ApiClient.scala

@@ -1,7 +1,7 @@
 package com.gu.facia.client
 
 import com.gu.etagcaching.FreshnessPolicy.AlwaysWaitForRefreshedValue
-import com.gu.etagcaching.aws.s3.ObjectId
+import com.gu.etagcaching.aws.s3.{ObjectId, S3ByteArrayFetching}
 import com.gu.etagcaching.fetching.Fetching
 import com.gu.etagcaching.{ConfigCache, ETagCache}
 import com.gu.facia.client.models.{CollectionJson, ConfigJson}
@@ -52,29 +52,31 @@ object ApiClient {
       throw JsonDeserialisationError(s"Could not deserialize JSON")
     }
 
+  /**
+   * @param s3Fetching eg `S3ObjectFetching.byteArrayWith(s3AsyncClient)`
+   */
   def withCaching(
     bucket: String,
     environment: Environment,
-    s3Fetching: Fetching[ObjectId, Array[Byte]], // Eg S3ObjectFetching(s3AsyncClient, Bytes).mapResponse(_.asByteArray())
+    s3Fetching: S3ByteArrayFetching,
     configureCollectionCache: ConfigCache = _.maximumSize(10000) // at most 1GB RAM worst case
-  )(implicit ec: ExecutionContext): ApiClient =
-    new ApiClient {
-      private val fetching =
-        s3Fetching.keyOn[String](path => ObjectId(bucket, path))
+  )(implicit ec: ExecutionContext): ApiClient = new ApiClient {
+    private val fetching =
+      s3Fetching.keyOn[String](path => ObjectId(bucket, path))
 
-      def eTagCache[B: Format](configureCache: ConfigCache) = new ETagCache(
-        fetching.thenParsing(parseBytes[B]),
-        AlwaysWaitForRefreshedValue,
-        configureCache
-      )
+    def eTagCache[B: Format](configureCache: ConfigCache) = new ETagCache(
+      fetching.thenParsing(parseBytes[B]),
+      AlwaysWaitForRefreshedValue,
+      configureCache
+    )
 
-      private val configCache = eTagCache[ConfigJson](_.maximumSize(1))
-      private val collectionCache = eTagCache[CollectionJson](configureCollectionCache)
+    private val configCache = eTagCache[ConfigJson](_.maximumSize(1))
+    private val collectionCache = eTagCache[CollectionJson](configureCollectionCache)
 
-      override def config: Future[ConfigJson] =
-        configCache.get(environment.configS3Path).map(getOrWarnAboutMissingConfig)
+    override def config: Future[ConfigJson] =
+      configCache.get(environment.configS3Path).map(getOrWarnAboutMissingConfig)
 
-      override def collection(id: String): Future[Option[CollectionJson]] =
-        collectionCache.get(environment.collectionS3Path(id))
-    }
+    override def collection(id: String): Future[Option[CollectionJson]] =
+      collectionCache.get(environment.collectionS3Path(id))
+  }
 }

fapi-client-core/src/main/scala/com/gu/facia/client/package.scala

@@ -0,0 +1,16 @@
+package com.gu.facia
+
+import com.gu.etagcaching.aws.s3.ObjectId
+import com.gu.etagcaching.fetching.Fetching
+
+package object client {
+  /**
+   * AWS SDK v2
+   *
+   * Add "com.gu.etag-caching" %% "aws-s3-sdk-v2" as dependency,
+   * import com.gu.etagcaching.aws.sdkv2.s3.S3ObjectFetching
+   *
+   * S3ObjectFetching.byteArrayWith(s3AsyncClient)
+   */
+  type S3FetchBehaviour = Fetching[ObjectId, Array[Byte]]
+}

fapi-client/src/test/scala/lib/IntegrationTestConfig.scala

@@ -30,11 +30,13 @@ trait IntegrationTestConfig extends ExecutionContext {
   def credentialsForDevAndCI(devProfile: String, ciCreds: AwsCredentialsProvider): AwsCredentialsProviderChain =
     AwsCredentialsProviderChain.of(ciCreds, ProfileCredentialsProvider.builder().profileName(devProfile).build())
 
+  private val s3AsyncClient: S3AsyncClient = S3AsyncClient.builder()
+    .region(Region.EU_WEST_1)
+    .credentialsProvider(credentialsForDevAndCI(awsProfileName, EnvironmentVariableCredentialsProvider.create())).build()
+
   implicit val apiClient: ApiClient = ApiClient.withCaching(
     "facia-tool-store",
     Environment.Dev,
-    S3ObjectFetching(S3AsyncClient.builder()
-      .region(Region.EU_WEST_1)
-      .credentialsProvider(credentialsForDevAndCI(awsProfileName, EnvironmentVariableCredentialsProvider.create())).build(), Bytes).mapResponse(_.asByteArray())
+    S3ObjectFetching.byteArrayWith(s3AsyncClient)
   )
 }

fapi-s3-sdk-v2/src/main/scala/com/gu/facia/client/aws/sdkv2/s3/AwsSdkV2.scala

@@ -10,6 +10,6 @@ import software.amazon.awssdk.services.s3.model.NoSuchKeyException
 
 case class AwsSdkV2(s3AsyncClient: S3AsyncClient) extends S3FetchBehaviour {
   override val fetching: Fetching[ObjectId, Array[Byte]] =
-    S3ObjectFetching(s3AsyncClient, Bytes).mapResponse(_.asByteArray())
+    com.gu.etagcaching.aws.sdkv2.s3.S3ObjectFetching.byteArrayWith(s3AsyncClient)
 
 }

project/dependencies.scala

@@ -2,7 +2,7 @@ import sbt._
 
 object Dependencies {
   val capiVersion = "32.0.0"
-  val eTagCachingVersion = "5.0.1"
+  val eTagCachingVersion = "5.0.3-SNAPSHOT"
 
   val awsS3SdkV1 = "com.amazonaws" % "aws-java-sdk-s3" % "1.12.765"
   val eTagCachingS3Base = "com.gu.etag-caching" %% "aws-s3-base" % eTagCachingVersion