- Change the parquet compression from "Snappy" to "Gzip", as there is an unhandleable exception when the app is running inside a Docker Container and uses the "Snappy" compression.

- Code polishing.

installAndRun.sh

@@ -48,7 +48,7 @@ if [[ justInstall -eq 0 ]]; then
   gradle clean build
 
   if [[ shouldRunInDocker -eq 1 ]]; then
-    echo "Give the username for the Docker Hub:"
+    echo -e "\nGive the username for the Docker Hub:"
     read -r username
     echo -e "\nBuilding docker image..\n"
     sudo docker --version || handle_error "Docker was not found!" 3

src/main/java/eu/openaire/urls_controller/controllers/UrlController.java

@@ -8,7 +8,6 @@ import eu.openaire.urls_controller.payloads.requests.WorkerReport;
 import eu.openaire.urls_controller.payloads.responces.AssignmentsResponse;
 import eu.openaire.urls_controller.util.FileUtils;
 import eu.openaire.urls_controller.util.ParquetFileUtils;
-import org.apache.commons.io.FileDeleteStrategy;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -20,7 +19,6 @@ import org.springframework.web.bind.annotation.*;
 
 import javax.servlet.http.HttpServletRequest;
 import java.io.File;
-import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.sql.Connection;
@@ -299,16 +297,12 @@ public class UrlController {
             logger.error(errorMsg, e);
             return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(errorMsg);
         } finally {
-            try {
-                logger.debug("Deleting directory: " + currentParquetPath);
-                FileDeleteStrategy.FORCE.delete(new File(currentParquetPath));
-            } catch (IOException e) {
-                logger.error("", e);
-            }
+            logger.debug("Deleting directory: " + currentParquetPath);
+            fileUtils.deleteDirectory(new File(currentParquetPath));
         }
 
         logger.debug("Going to merge the parquet files for the tables which were altered.");
-        // When the uploaded parquet files are "loaded" into the tables, ther are actually moved into the directory which contains the data of the table.
+        // When the uploaded parquet files are "loaded" into the tables, they are actually moved into the directory which contains the data of the table.
 
         String mergeErrorMsg;
 

src/main/java/eu/openaire/urls_controller/util/ParquetFileUtils.java

@@ -314,7 +314,7 @@ public class ParquetFileUtils {
         }
 
         try (ParquetWriter<GenericRecord> writer = AvroParquetWriter.<GenericRecord>builder(outputFile).withSchema(schema)
-                                                                    .withCompressionCodec(CompressionCodecName.SNAPPY).build())
+                                                                    .withCompressionCodec(CompressionCodecName.GZIP).build())
         {
             //logger.debug("Going to write to \"" + fullFilePath + "\" the record list: " + recordList);  // DEBUG!
             for ( GenericRecord record : recordList ) {
@@ -322,7 +322,7 @@ public class ParquetFileUtils {
                 writer.write(record);
             }
         } catch (Throwable e) { // The simple "Exception" may not be thrown here, but an "Error" may be thrown. "Throwable" catches EVERYTHING!
-            logger.error("Problem when creating the \"ParquetWriter\" object or when writing a record with it!", e);
+            logger.error("Problem when creating the \"ParquetWriter\" object or when writing the records with it!", e);
             // At some point, I got an "NoSuchMethodError", because of a problem in the AvroSchema file: (java.lang.NoSuchMethodError: org.apache.avro.Schema.getLogicalType()Lorg/apache/avro/LogicalType;).
             // The error was with the schema: {"name": "date", "type" : ["null", {"type" : "long", "logicalType" : "timestamp-millis"}]},
             return false;

src/main/java/eu/openaire/urls_controller/util/S3ObjectStore.java

@@ -18,7 +18,7 @@ public class S3ObjectStore {
 
     private static final Logger logger = LoggerFactory.getLogger(S3ObjectStore.class);
 
-    private String s3Protocol = "s3://";
+    private final String s3Protocol = "s3://";
     @Value("${services.pdfaggregation.controller.s3.endpoint}")
     private String endpoint = null;   // This is useful to be "public", to test file-locations.
     @Value("${services.pdfaggregation.controller.s3.accessKey}")