[s3client] objectHead returns an IO[Option[...]]

If the remote file is missing then return None.

S3MetaDataEnricher.enrichWithS3MetaData now returns an IO[Either[File,
S3MetaData]]. If objectHead returns None, the this returns the file,
otherwise, the Some[Hash, LastModified] from objectHead is used to
create the S3MetaData as before.

src/main/scala/net/kemitix/s3thorp/ReactiveS3Client.scala

@@ -17,6 +17,6 @@ class ReactiveS3Client extends S3Client {
     for {
       response <- s3Client.headObject(request)
       // TODO catch 404 error when key doesn't exist
-    } yield (response.eTag(), response.lastModified())
+    } yield Some((response.eTag(), response.lastModified()))
   }
 }

src/main/scala/net/kemitix/s3thorp/S3Client.scala

@@ -5,6 +5,6 @@ import net.kemitix.s3thorp.Sync.{Hash, LastModified}
 
 trait S3Client {
 
-  def objectHead(bucket: String, key: String): IO[(Hash, LastModified)]
+  def objectHead(bucket: String, key: String): IO[Option[(Hash, LastModified)]]
 
 }

src/main/scala/net/kemitix/s3thorp/S3MetaDataEnricher.scala

@@ -12,14 +12,16 @@ trait S3MetaDataEnricher extends S3Client {
     s"${c.prefix}/${c.source.toPath.relativize(file.toPath)}"
   }
 
-  def enrichWithS3MetaData(c: Config): File => Stream[IO, S3MetaData] = {
+  def enrichWithS3MetaData(c: Config): File => Stream[IO, Either[File, S3MetaData]] = {
     val fileToString = generateKey(c)_
     file =>
       Stream.eval(for {
         _ <- putStrLn(s"enrich: $file")
         key = fileToString(file)
         head <- objectHead(c.bucket, key)
-        (hash, lastModified) = head
-      } yield S3MetaData(file, key, hash, lastModified))
+      } yield head.map {
+        case (hash,lastModified) =>
+          Right(S3MetaData(file, key, hash, lastModified))
+      }.getOrElse(Left(file)))
   }
 }

src/main/scala/net/kemitix/s3thorp/Sync.scala

@@ -24,12 +24,15 @@ class Sync(s3Client: S3Client) extends LocalFileStream with S3MetaDataEnricher {
     }
   } yield ()
 
-  private def uploadRequiredFilter: S3MetaData => Stream[IO, File] = s3Metadata => Stream.eval(for {
+  private def uploadRequiredFilter: Either[File, S3MetaData] => Stream[IO, File] = {
+    case Left(file) => Stream(file)
+    case Right(s3Metadata) =>
+      Stream.eval(for {
         _ <- putStrLn(s"upload required: ${s3Metadata.localFile}")
         //md5File(localFile)
         //filter(localHash => options.force || localHash != metadataHash)
       } yield s3Metadata.localFile)
-
+  }
   private def performUpload: File => Stream[IO, Promise[Unit]] =
     file => Stream.eval(for {
       _ <- putStrLn(s"upload: $file")

src/test/scala/net/kemitix/s3thorp/SyncSuite.scala

@@ -11,11 +11,11 @@ class SyncSuite extends FunSpec {
     val hash = "hash"
     val lastModified = Instant.now()
     val sync = new Sync(new S3Client {
-      override def objectHead(bucket: String, key: String) = IO((hash, lastModified))
+      override def objectHead(bucket: String, key: String) = IO(Some((hash, lastModified)))
     })
     describe("objectHead") {
       it("return the hash and lastModified expected") {
-        assertResult((hash, lastModified))(sync.objectHead("", "").unsafeRunSync())
+        assertResult(Some((hash, lastModified)))(sync.objectHead("", "").unsafeRunSync())
       }
     }
   }