fix: Improved memory usage

src/main/java/it/gov/pagopa/receipt/pdf/datastore/GenerateReceiptPdf.java

@@ -132,7 +132,7 @@ public void processGenerateReceipt(
                 boolean generateOnlyDebtor = payerCF == null || payerCF.equals(debtorCF);
 
                 //Generate and save PDF
-                PdfGeneration pdfGeneration = service.handlePdfsGeneration(generateOnlyDebtor, receipt, bizEvent, debtorCF, payerCF);
+                PdfGeneration pdfGeneration = service.handlePdfsGeneration(generateOnlyDebtor, receipt, bizEvent, debtorCF, payerCF, logger);
 
                 //Write PDF blob storage metadata on receipt
                 numberOfSavedPdfs = service.addPdfsMetadataToReceipt(receipt, pdfGeneration);

src/main/java/it/gov/pagopa/receipt/pdf/datastore/client/ReceiptBlobClient.java

@@ -2,7 +2,9 @@
 
 import it.gov.pagopa.receipt.pdf.datastore.model.response.BlobStorageResponse;
 
+import java.io.InputStream;
+
 public interface ReceiptBlobClient {
 
-    BlobStorageResponse savePdfToBlobStorage(byte[] pdf, String fileName);
+    BlobStorageResponse savePdfToBlobStorage(InputStream pdf, String fileName);
 }

src/main/java/it/gov/pagopa/receipt/pdf/datastore/client/impl/PdfEngineClientImpl.java

@@ -5,22 +5,24 @@
 import it.gov.pagopa.receipt.pdf.datastore.model.request.PdfEngineRequest;
 import it.gov.pagopa.receipt.pdf.datastore.model.response.PdfEngineResponse;
 import it.gov.pagopa.receipt.pdf.datastore.utils.ObjectMapperUtils;
+import org.apache.commons.io.FileUtils;
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpStatus;
 import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.entity.ContentType;
 import org.apache.http.entity.mime.HttpMultipartMode;
 import org.apache.http.entity.mime.MultipartEntityBuilder;
-import org.apache.http.entity.mime.content.ByteArrayBody;
 import org.apache.http.entity.mime.content.StringBody;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.util.EntityUtils;
 
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
 
 /**
  * Client for the PDF Engine
@@ -67,13 +69,13 @@ public PdfEngineResponse generatePDF(PdfEngineRequest pdfEngineRequest) {
         //Generate client
         try (CloseableHttpClient client = this.httpClientBuilder.build()) {
             //Encode template and data
-            ByteArrayBody fileBody = new ByteArrayBody(pdfEngineRequest.getTemplate(), ZIP_FILE_NAME);
+
             StringBody dataBody = new StringBody(pdfEngineRequest.getData(), ContentType.APPLICATION_JSON);
 
             //Build the multipart request
             MultipartEntityBuilder builder = MultipartEntityBuilder.create();
             builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
-            builder.addPart(TEMPLATE_KEY, fileBody);
+            builder.addBinaryBody(TEMPLATE_KEY, pdfEngineRequest.getTemplate(), ContentType.create("application/zip"), ZIP_FILE_NAME);
             builder.addPart(DATA_KEY, dataBody);
             HttpEntity entity = builder.build();
 
@@ -82,9 +84,9 @@ public PdfEngineResponse generatePDF(PdfEngineRequest pdfEngineRequest) {
             request.setHeader(HEADER_AUTH_KEY, ocpAimSubKey);
             request.setEntity(entity);
 
-            handlePdfEngineResponse(pdfEngineResponse, client, request);
+            pdfEngineResponse = handlePdfEngineResponse(client, request);
         } catch (IOException e) {
-            pdfEngineResponse.setStatusCode(HttpStatus.SC_INTERNAL_SERVER_ERROR);
+            handleExceptionErrorMessage(pdfEngineResponse, e);
         }
 
         return pdfEngineResponse;
@@ -93,31 +95,66 @@ public PdfEngineResponse generatePDF(PdfEngineRequest pdfEngineRequest) {
     /**
      * Calls the PDF Engine and handles its response, updating the PdfEngineResponse accordingly
      *
-     * @param pdfEngineResponse Response output
-     * @param client            The previously generated client
-     * @param request           The request to the PDF engine
+     * @param client  The previously generated client
+     * @param request The request to the PDF engine
+     * @return pdf engine response
      */
-    private static void handlePdfEngineResponse(PdfEngineResponse pdfEngineResponse, CloseableHttpClient client, HttpPost request) {
+    private static PdfEngineResponse handlePdfEngineResponse(CloseableHttpClient client, HttpPost request) {
+        PdfEngineResponse pdfEngineResponse = new PdfEngineResponse();
         //Execute call
         try (CloseableHttpResponse response = client.execute(request)) {
             //Retrieve response
             HttpEntity entityResponse = response.getEntity();
 
             //Handles response
             if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK && entityResponse != null) {
-                InputStream inputStream = entityResponse.getContent();
+                try (InputStream inputStream = entityResponse.getContent()) {
+                    pdfEngineResponse.setStatusCode(HttpStatus.SC_OK);
 
-                pdfEngineResponse.setStatusCode(HttpStatus.SC_OK);
-                pdfEngineResponse.setPdf(inputStream.readAllBytes());
+                    saveTempPdf(pdfEngineResponse, inputStream);
+                }
             } else {
                 pdfEngineResponse.setStatusCode(HttpStatus.SC_INTERNAL_SERVER_ERROR);
 
                 handleErrorResponse(pdfEngineResponse, response, entityResponse);
             }
+        } catch (Exception e) {
+            handleExceptionErrorMessage(pdfEngineResponse, e);
+        }
 
-        } catch (IOException e) {
-            pdfEngineResponse.setStatusCode(HttpStatus.SC_INTERNAL_SERVER_ERROR);
+        return pdfEngineResponse;
+    }
+
+    /**
+     * Saves pdf as temporary file
+     *
+     * @param pdfEngineResponse Pdf engine response
+     * @param inputStream       InputStream pdf
+     * @throws IOException In case of error to save
+     */
+    private static void saveTempPdf(PdfEngineResponse pdfEngineResponse, InputStream inputStream) throws IOException {
+        File tempDirectory = new File("temp");
+        if (!tempDirectory.exists()) {
+            Files.createDirectory(tempDirectory.toPath());
         }
+
+        File targetFile = File.createTempFile("tempFile", ".pdf", tempDirectory);
+
+        FileUtils.copyInputStreamToFile(inputStream, targetFile);
+
+        pdfEngineResponse.setTempPdfPath(targetFile.getAbsolutePath());
+        pdfEngineResponse.setTempDirectoryPath(tempDirectory.getAbsolutePath());
+    }
+
+    /**
+     * Handles error message in case of error thrown
+     *
+     * @param pdfEngineResponse Pdf engine respone
+     * @param e                 Error thrown
+     */
+    private static void handleExceptionErrorMessage(PdfEngineResponse pdfEngineResponse, Exception e) {
+        pdfEngineResponse.setStatusCode(HttpStatus.SC_INTERNAL_SERVER_ERROR);
+        pdfEngineResponse.setErrorMessage(String.format("Exception thrown during pdf generation process: %s", e));
     }
 
     /**
@@ -128,9 +165,16 @@ private static void handlePdfEngineResponse(PdfEngineResponse pdfEngineResponse,
      * @param entityResponse    Response content from the PDF Engine
      * @throws IOException in case of error encoding to string
      */
-    private static void handleErrorResponse(PdfEngineResponse pdfEngineResponse, CloseableHttpResponse response, HttpEntity entityResponse) throws IOException {
+    private static void handleErrorResponse(
+            PdfEngineResponse pdfEngineResponse,
+            CloseableHttpResponse response,
+            HttpEntity entityResponse
+    ) throws IOException {
         //Verify if unauthorized
-        if (response.getStatusLine().getStatusCode() == HttpStatus.SC_UNAUTHORIZED) {
+        if (response != null &&
+                response.getStatusLine() != null &&
+                response.getStatusLine().getStatusCode() == HttpStatus.SC_UNAUTHORIZED
+        ) {
             pdfEngineResponse.setErrorMessage("Unauthorized call to PDF engine function");
 
         } else if (entityResponse != null) {

src/main/java/it/gov/pagopa/receipt/pdf/datastore/client/impl/ReceiptBlobClientImpl.java

@@ -11,7 +11,7 @@
 import it.gov.pagopa.receipt.pdf.datastore.client.ReceiptBlobClient;
 import it.gov.pagopa.receipt.pdf.datastore.model.response.BlobStorageResponse;
 
-import java.io.ByteArrayInputStream;
+import java.io.InputStream;
 
 /**
  * Client for the Blob Storage
@@ -55,7 +55,7 @@ public static ReceiptBlobClientImpl getInstance() {
      * @param fileName Filename to save the PDF with
      * @return blob storage response with PDF metadata or error message and status
      */
-    public BlobStorageResponse savePdfToBlobStorage(byte[] pdf, String fileName) {
+    public BlobStorageResponse savePdfToBlobStorage(InputStream pdf, String fileName) {
 
         //Create the container and return a container client object
         BlobContainerClient blobContainerClient = this.blobServiceClient.getBlobContainerClient(containerName);
@@ -67,7 +67,7 @@ public BlobStorageResponse savePdfToBlobStorage(byte[] pdf, String fileName) {
         //Upload the blob
         Response<BlockBlobItem> blockBlobItemResponse = blobClient.uploadWithResponse(
                 new BlobParallelUploadOptions(
-                        new ByteArrayInputStream(pdf)
+                        pdf
                 ), null, null);
 
         BlobStorageResponse blobStorageResponse = new BlobStorageResponse();

src/main/java/it/gov/pagopa/receipt/pdf/datastore/model/request/PdfEngineRequest.java

@@ -4,6 +4,8 @@
 import lombok.NoArgsConstructor;
 import lombok.Setter;
 
+import java.io.InputStream;
+
 /**
  * Model class for PDF engine request
  */
@@ -12,7 +14,7 @@
 @NoArgsConstructor
 public class PdfEngineRequest {
 
-    byte[] template;
+    InputStream template;
     String data;
     boolean applySignature;
 }

src/main/java/it/gov/pagopa/receipt/pdf/datastore/model/response/PdfEngineResponse.java

@@ -12,7 +12,8 @@
 @NoArgsConstructor
 public class PdfEngineResponse {
 
-    byte[] pdf;
+    String tempDirectoryPath;
+    String tempPdfPath;
     int statusCode;
     String errorMessage;
 

src/main/java/it/gov/pagopa/receipt/pdf/datastore/service/GenerateReceiptPdfService.java

@@ -20,6 +20,8 @@
 import lombok.NoArgsConstructor;
 import org.apache.http.HttpStatus;
 
+import java.io.*;
+import java.nio.file.Files;
 import java.time.LocalDateTime;
 import java.util.logging.Logger;
 
@@ -38,7 +40,7 @@ public class GenerateReceiptPdfService {
      * @param payerCF            Payer fiscal code
      * @return PdfGeneration object with the PDF metadata from the Blob Storage or relatives error messages
      */
-    public PdfGeneration handlePdfsGeneration(boolean generateOnlyDebtor, Receipt receipt, BizEvent bizEvent, String debtorCF, String payerCF) {
+    public PdfGeneration handlePdfsGeneration(boolean generateOnlyDebtor, Receipt receipt, BizEvent bizEvent, String debtorCF, String payerCF, Logger logger) {
         PdfGeneration pdfGeneration = new PdfGeneration();
 
         if (generateOnlyDebtor) {
@@ -48,7 +50,7 @@ public PdfGeneration handlePdfsGeneration(boolean generateOnlyDebtor, Receipt re
                             receipt.getMdAttach().getUrl() == null ||
                             receipt.getMdAttach().getUrl().isEmpty())
             ) {
-                pdfGeneration.setDebtorMetadata(generatePdf(bizEvent, debtorCF, true));
+                pdfGeneration.setDebtorMetadata(generatePdf(bizEvent, debtorCF, true, logger));
             }
         } else {
             //Generate debtor's partial PDF
@@ -57,15 +59,15 @@ public PdfGeneration handlePdfsGeneration(boolean generateOnlyDebtor, Receipt re
                             receipt.getMdAttach().getUrl() == null ||
                             receipt.getMdAttach().getUrl().isEmpty())
             ) {
-                pdfGeneration.setDebtorMetadata(generatePdf(bizEvent, debtorCF, false));
+                pdfGeneration.setDebtorMetadata(generatePdf(bizEvent, debtorCF, false, logger));
             }
             //Generate payer's complete PDF
             if (payerCF != null &&
                     (receipt.getMdAttachPayer() == null ||
                             receipt.getMdAttachPayer().getUrl() == null ||
                             receipt.getMdAttachPayer().getUrl().isEmpty())
             ) {
-                pdfGeneration.setPayerMetadata(generatePdf(bizEvent, payerCF, true));
+                pdfGeneration.setPayerMetadata(generatePdf(bizEvent, payerCF, true, logger));
             }
         }
 
@@ -80,7 +82,7 @@ public PdfGeneration handlePdfsGeneration(boolean generateOnlyDebtor, Receipt re
      * @param completeTemplate Boolean that indicates what template to use
      * @return PDF metadata retrieved from Blob Storage or relative error message
      */
-    private PdfMetadata generatePdf(BizEvent bizEvent, String fiscalCode, boolean completeTemplate) {
+    private PdfMetadata generatePdf(BizEvent bizEvent, String fiscalCode, boolean completeTemplate, Logger logger) {
         PdfEngineRequest request = new PdfEngineRequest();
         PdfMetadata response = new PdfMetadata();
 
@@ -90,12 +92,9 @@ private PdfMetadata generatePdf(BizEvent bizEvent, String fiscalCode, boolean co
 
         String fileName = completeTemplate ? completeTemplateFileName : partialTemplateFileName;
 
-        try {
-            //File to byte[]
-            byte[] htmlTemplate = GenerateReceiptPdf.class.getClassLoader().getResourceAsStream(fileName).readAllBytes();
-
+        try (InputStream templateStream = GenerateReceiptPdf.class.getClassLoader().getResourceAsStream(fileName)) {
             //Build the request
-            request.setTemplate(htmlTemplate);
+            request.setTemplate(templateStream);
             request.setData(ObjectMapperUtils.writeValueAsString(TemplateMapperUtils.convertReceiptToPdfData(bizEvent)));
 
             request.setApplySignature(false);
@@ -109,7 +108,7 @@ private PdfMetadata generatePdf(BizEvent bizEvent, String fiscalCode, boolean co
                 //Save the PDF
                 String pdfFileName = bizEvent.getId() + fiscalCode;
 
-                handleSaveToBlobStorage(response, pdfEngineResponse, pdfFileName);
+                handleSaveToBlobStorage(pdfEngineResponse, response, pdfFileName, logger);
 
             } else {
                 //Handle PDF generation error
@@ -129,18 +128,20 @@ private PdfMetadata generatePdf(BizEvent bizEvent, String fiscalCode, boolean co
     /**
      * Handles saving PDF to Blob Storage
      *
-     * @param response          Pdf metadata containing response
-     * @param pdfEngineResponse Response from the pdf engine
-     * @param pdfFileName       Filename composed of biz-event id and user fiscal code
+     * @param response    Pdf metadata containing response
+     * @param pdfFileName Filename composed of biz-event id and user fiscal code
      */
-    private void handleSaveToBlobStorage(PdfMetadata response, PdfEngineResponse pdfEngineResponse, String pdfFileName) {
+    private void handleSaveToBlobStorage(PdfEngineResponse pdfEngineResponse, PdfMetadata response, String pdfFileName, Logger logger) {
         BlobStorageResponse blobStorageResponse;
 
         ReceiptBlobClientImpl blobClient = ReceiptBlobClientImpl.getInstance();
 
+        String tempPdfPath = pdfEngineResponse.getTempPdfPath();
+        String tempDirectoryPath = pdfEngineResponse.getTempDirectoryPath();
+
         //Save to Blob Storage
-        try {
-            blobStorageResponse = blobClient.savePdfToBlobStorage(pdfEngineResponse.getPdf(), pdfFileName);
+        try (BufferedInputStream pdfStream = new BufferedInputStream(new FileInputStream(tempPdfPath))) {
+            blobStorageResponse = blobClient.savePdfToBlobStorage(pdfStream, pdfFileName);
 
             if (blobStorageResponse.getStatusCode() == com.microsoft.azure.functions.HttpStatus.CREATED.value()) {
                 //Update PDF metadata
@@ -160,6 +161,39 @@ private void handleSaveToBlobStorage(PdfMetadata response, PdfEngineResponse pdf
             response.setStatusCode(ReasonErrorCode.ERROR_BLOB_STORAGE.getCode());
             response.setErrorMessage("Error saving pdf to blob storage : " + e);
         }
+
+        deleteTempFolderAndFile(tempPdfPath, tempDirectoryPath, logger);
+    }
+
+    /**
+     * Delete temporary file and director created for the generated PDF
+     *
+     * @param tempPdfPath       Path to the temp PDF file
+     * @param tempDirectoryPath Path to the temp directory containing the PDF file
+     * @param logger            Logger
+     */
+    private static void deleteTempFolderAndFile(String tempPdfPath, String tempDirectoryPath, Logger logger) {
+        String logMsg;
+
+        File tempFile = new File(tempPdfPath);
+        if (tempFile.exists()) {
+            try {
+                Files.delete(tempFile.toPath());
+            } catch (IOException e) {
+                logMsg = String.format("Error deleting temporary pdf file from file system: %s", e);
+                logger.warning(logMsg);
+            }
+        }
+
+        File tempDirectory = new File(tempDirectoryPath);
+        if (tempDirectory.exists()) {
+            try {
+                Files.delete(tempDirectory.toPath());
+            } catch (IOException e) {
+                logMsg = String.format("Error deleting temporary pdf directory from file system: %s", e);
+                logger.warning(logMsg);
+            }
+        }
     }