feat: add startup and document save failure logs for improved debugging

src/main/scala/org/dbpedia/databus/ApiImpl.scala

@@ -18,13 +18,16 @@ import virtuoso.jdbc4.VirtuosoException
 
 import scala.util.{Failure, Success, Try}
 import scala.xml.Node
+import org.slf4j.LoggerFactory
 import collection.JavaConverters._
 
 
 class ApiImpl(config: Config) extends DatabusApi {
 
   import ApiImpl._
 
+  private lazy val log = LoggerFactory.getLogger(this.getClass)
+
   private val client: GitClient = initGitClient(config)
   private val defaultLang = Lang.JSONLD
   private lazy val sparqlClient: SparqlClient = SparqlClient.get(config)
@@ -165,6 +168,15 @@ class ApiImpl(config: Config) extends DatabusApi {
     } else {
       Success(Unit)
     }).flatMap(_ => client.commitSeveralFiles(username, fullFilenamesAndData))
+      .recoverWith {
+        case err: Throwable =>
+          try {
+            log.error(s"Failed to save files for user '$username' (${fullFilenamesAndData.keys.mkString(",")})", err)
+          } catch {
+            case _: Throwable => // ignore logging failures
+          }
+          Failure(err)
+      }
 
 
   private def deleteFileFromGit(username: String, path: String)(request: HttpServletRequest): Try[String] = {

src/main/scala/org/dbpedia/databus/JettyLauncher.scala

@@ -39,6 +39,13 @@ object JettyLauncher { // this is my entry object as specified in sbt project de
       .map(ApiImpl.Config.fromWebXml)
       .getOrElse(ApiImpl.Config.default)
 
+    if (config.gitLocalDir.isDefined) {
+      log.info(s"Using local git directory: ${config.gitLocalDir.get.toAbsolutePath}")
+      log.info("Attempting to cache local development context (if present)")
+    } else {
+      log.info("No local git directory configured; using remote git API (if configured)")
+    }
+
     val browserPath = "/file"
     val fileListHandler = config.gitLocalDir
       .flatMap(p => Try(fileBrowserContext(p, browserPath)).toOption)

src/main/scala/org/dbpedia/databus/SparqlClient.scala

@@ -146,14 +146,21 @@ class FusekiJDBCClient(host: String, port: Int, user: String, pass: String, data
 }
 
 object RdfConversions {
+  private lazy val log = LoggerFactory.getLogger(this.getClass)
 
   private val DefaultShaclLang = Lang.TTL
 
   def readModel(data: Array[Byte], lang: Lang): Try[Model] = Try {
     val model = ModelFactory.createDefaultModel()
     val dataStream = new ByteArrayInputStream(data)
-    RDFDataMgr.read(model, dataStream, lang)
-    model
+    try {
+      RDFDataMgr.read(model, dataStream, lang)
+      model
+    } catch {
+      case e: Throwable =>
+        log.error(s"Failed to parse input as ${lang.getName}: ${e.getMessage}")
+        throw e
+    }
   }
 
   def validateWithShacl(model: Model, shacl: Graph): Try[ValidationReport] =