Move invoice generation to billing bucket and improve emailing

This moves the new pipeline's invoice generation to the billing bucket, under the 'invoices/yyyy-MM' subdirectory.

This also changes the invoice e-mail to use a multipart message that attaches the invoice to the e-mail, to guarantee the correct MIME type and download.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=181746191

java/google/registry/billing/BillingEmailUtils.java

@@ -14,15 +14,29 @@
 
 package google.registry.billing;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.appengine.tools.cloudstorage.GcsFilename;
 import com.google.common.collect.ImmutableList;
+import com.google.common.io.CharStreams;
+import google.registry.billing.BillingModule.InvoiceDirectoryPrefix;
 import google.registry.config.RegistryConfig.Config;
+import google.registry.gcs.GcsUtils;
 import google.registry.util.FormattingLogger;
+import google.registry.util.Retrier;
 import google.registry.util.SendEmailService;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
 import javax.inject.Inject;
+import javax.mail.BodyPart;
 import javax.mail.Message;
 import javax.mail.Message.RecipientType;
 import javax.mail.MessagingException;
+import javax.mail.Multipart;
 import javax.mail.internet.InternetAddress;
+import javax.mail.internet.MimeBodyPart;
+import javax.mail.internet.MimeMultipart;
 import org.joda.time.YearMonth;
 
 /** Utility functions for sending emails involving monthly invoices. */
@@ -31,55 +45,104 @@ class BillingEmailUtils {
   private final SendEmailService emailService;
   private final YearMonth yearMonth;
   private final String alertSenderAddress;
+  private final String alertRecipientAddress;
   private final ImmutableList<String> invoiceEmailRecipients;
-  // TODO(larryruili): Replace this bucket after verifying 2017-12 output.
-  private final String beamBucketUrl;
+  private final String billingBucket;
+  private final String invoiceDirectoryPrefix;
+  private final GcsUtils gcsUtils;
+  private final Retrier retrier;
 
   @Inject
   BillingEmailUtils(
       SendEmailService emailService,
       YearMonth yearMonth,
       @Config("alertSenderEmailAddress") String alertSenderAddress,
+      @Config("alertRecipientEmailAddress") String alertRecipientAddress,
       @Config("invoiceEmailRecipients") ImmutableList<String> invoiceEmailRecipients,
-      @Config("apacheBeamBucketUrl") String beamBucketUrl) {
+      @Config("billingBucket") String billingBucket,
+      @InvoiceDirectoryPrefix String invoiceDirectoryPrefix,
+      GcsUtils gcsUtils,
+      Retrier retrier) {
     this.emailService = emailService;
     this.yearMonth = yearMonth;
     this.alertSenderAddress = alertSenderAddress;
+    this.alertRecipientAddress = alertRecipientAddress;
     this.invoiceEmailRecipients = invoiceEmailRecipients;
-    this.beamBucketUrl = beamBucketUrl;
+    this.billingBucket = billingBucket;
+    this.invoiceDirectoryPrefix = invoiceDirectoryPrefix;
+    this.gcsUtils = gcsUtils;
+    this.retrier = retrier;
   }
 
   private static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();
 
-  /**
-   * Sends a link to the generated overall invoice in GCS.
-   *
-   * <p>Note the users receiving the e-mail should have access to the object or bucket, via an
-   * authorization mechanism such as IAM.
-   */
-  void emailInvoiceLink() {
-    // TODO(larryruili): Add read permissions for appropriate buckets.
-    try {
-      String beamBucket = beamBucketUrl.replaceFirst("gs://", "");
-      Message msg = emailService.createMessage();
-      msg.setFrom(new InternetAddress(alertSenderAddress));
-      for (String recipient : invoiceEmailRecipients) {
-        msg.addRecipient(RecipientType.TO, new InternetAddress(recipient));
-      }
-      msg.setSubject(String.format("Domain Registry invoice data %s", yearMonth.toString()));
-      msg.setText(
-          String.format(
-              "Link to invoice on GCS:\nhttps://storage.cloud.google.com/%s/%s",
-              beamBucket,
+  /** Sends an e-mail to all expected recipients with an attached overall invoice from GCS. */
+  void emailOverallInvoice() {
+    retrier.callWithRetry(
+        () -> {
+          String invoiceFile =
               String.format(
-                  "%s%s-%s.csv",
-                  BillingModule.RESULTS_DIRECTORY_PREFIX,
-                  BillingModule.OVERALL_INVOICE_PREFIX,
-                  yearMonth.toString())));
-      emailService.sendMessage(msg);
-    } catch (MessagingException e) {
-      // TODO(larryruili): Replace with retrier with final failure email settings.
-      logger.warning(e, "E-mail service failed due to %s");
-    }
+                  "%s-%s.csv", BillingModule.OVERALL_INVOICE_PREFIX, yearMonth.toString());
+          GcsFilename invoiceFilename =
+              new GcsFilename(billingBucket, invoiceDirectoryPrefix + invoiceFile);
+          try (InputStream in = gcsUtils.openInputStream(invoiceFilename)) {
+            Message msg = emailService.createMessage();
+            msg.setFrom(new InternetAddress(alertSenderAddress));
+            for (String recipient : invoiceEmailRecipients) {
+              msg.addRecipient(RecipientType.TO, new InternetAddress(recipient));
+            }
+            msg.setSubject(String.format("Domain Registry invoice data %s", yearMonth.toString()));
+            Multipart multipart = new MimeMultipart();
+            BodyPart textPart = new MimeBodyPart();
+            textPart.setText(
+                String.format(
+                    "Attached is the %s invoice for the domain registry.", yearMonth.toString()));
+            multipart.addBodyPart(textPart);
+            BodyPart invoicePart = new MimeBodyPart();
+            String invoiceData = CharStreams.toString(new InputStreamReader(in, UTF_8));
+            invoicePart.setContent(invoiceData, "text/csv; charset=utf-8");
+            invoicePart.setFileName(invoiceFile);
+            multipart.addBodyPart(invoicePart);
+            msg.setContent(multipart);
+            msg.saveChanges();
+            emailService.sendMessage(msg);
+          }
+        },
+        new Retrier.FailureReporter() {
+          @Override
+          public void beforeRetry(Throwable thrown, int failures, int maxAttempts) {}
+
+          @Override
+          public void afterFinalFailure(Throwable thrown, int failures) {
+            sendAlertEmail(
+                String.format("Emailing invoice failed due to %s", thrown.getMessage()));
+          }
+        },
+        IOException.class,
+        MessagingException.class);
+  }
+
+  /** Sends an e-mail to the provided alert e-mail address indicating a billing failure. */
+  void sendAlertEmail(String body) {
+    retrier.callWithRetry(
+        () -> {
+          Message msg = emailService.createMessage();
+          msg.setFrom(new InternetAddress(alertSenderAddress));
+          msg.addRecipient(RecipientType.TO, new InternetAddress(alertRecipientAddress));
+          msg.setSubject(String.format("Billing Pipeline Alert: %s", yearMonth.toString()));
+          msg.setText(body);
+          emailService.sendMessage(msg);
+          return null;
+        },
+        new Retrier.FailureReporter() {
+          @Override
+          public void beforeRetry(Throwable thrown, int failures, int maxAttempts) {}
+
+          @Override
+          public void afterFinalFailure(Throwable thrown, int failures) {
+            logger.severe(thrown, "The alert e-mail system failed.");
+          }
+        },
+        MessagingException.class);
   }
 }