package mireka.transmission.queue;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.util.Arrays;
import java.util.NavigableSet;
import java.util.Properties;
import java.util.TreeSet;
import javax.annotation.concurrent.GuardedBy;
import mireka.MailData;
import mireka.smtp.EnhancedStatus;
import mireka.transmission.Mail;
import mireka.transmission.queue.dataprop.DataProperties;
import mireka.util.StreamCopier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* FileDirStore stores scheduled mails in the file system in a single directory.
* Mails are stored in two files. A properties file contains the envelope
* information and a binary file contains the message content. In order to
* provide some consistency in case of a system failure, the two files are
* created and deleted in a specific order. On creation first the message
* content file is saved, then the properties file. On deletion the order is the
* opposite, the properties file is deleted first. The two files have the same
* name but with different extension (.properties and .eml). The name is the
* scheduled date with an additional serial number if it is necessary, so it
* become a unique.
*/
public class FileDirStore {
private final Logger logger = LoggerFactory.getLogger(FileDirStore.class);
private File dir;
/**
* The allowed count of mails in the store.
*/
private int maxSize = 2000;
/**
* The mail names currently allocated, in the usual circumstances these
* corresponds to the mails currently scheduled and are residing in the
* directory. If a mail for some reason cannot be deleted, then its name
* will remain in this collection, until a system restart.
*/
@GuardedBy("this")
private final NavigableSet<MailName> mailNames = new TreeSet<MailName>();
/**
* True if {@link #initializeAndQueryMailNamesOrderedBySchedule()} is called
* and it was successful. This must be the first operation which is called
* on a new instance.
*/
@GuardedBy("this")
private boolean initialized;
/**
* use this constructor with setters
*/
public FileDirStore() {
// nothing to do
}
public FileDirStore(File dir, int maxQueueSize) {
this.dir = dir;
this.maxSize = maxQueueSize;
}
/**
* this function must be called before any other method, and it cannot be
* called more then once.
*
* @throws QueueStorageException
* if the store cannot be initialized for some reason.
*/
public synchronized MailName[] initializeAndQueryMailNamesOrderedBySchedule()
throws QueueStorageException {
try {
MailName[] mailNamesArray = queryMailNames();
mailNames.addAll(Arrays.asList(mailNamesArray));
initialized = true;
logger.info("Mail store initialized with " + mailNamesArray.length
+ " mails in " + dir);
return mailNamesArray;
} catch (IOException e) {
throw new QueueStorageException(e,
EnhancedStatus.TRANSIENT_LOCAL_ERROR_IN_PROCESSING);
}
}
private MailName[] queryMailNames() throws IOException {
String[] names = listEnvelopeFileNames();
MailName[] mailNames = convertFileNamesToMailNames(names);
Arrays.sort(mailNames);
return mailNames;
}
private String[] listEnvelopeFileNames() throws IOException {
String[] names = dir.list(new FilenameFilter() {
@Override
public boolean accept(File dir, String name) {
return name.endsWith(MailName.MESSAGE_ENVELOPE_DOT_EXTENSION);
}
});
if (names == null)
throw new IOException("Cannot list directory: " + dir);
return names;
}
private MailName[] convertFileNamesToMailNames(String[] names) {
MailName[] mailNames = new MailName[names.length];
for (int i = 0; i < names.length; i++) {
mailNames[i] = new MailName(names[i]);
}
return mailNames;
}
public MailName save(Mail srcMail) throws QueueStorageException {
MailName mailName = allocateMailName(srcMail);
File contentFile = contentFileForName(mailName);
File envelopeFile = envelopeFileForName(mailName);
try {
writeMessageContentIntoFile(srcMail.mailData,
contentFileForName(mailName));
} catch (IOException e) {
if (contentFile.exists() && !contentFile.delete()) {
logger.error("Writing to the message content file failed, the "
+ "file exists, and it could not be deleted: "
+ contentFile);
} else {
releaseMailName(mailName);
}
throw new QueueStorageException(e, EnhancedStatus.MAIL_SYSTEM_FULL);
}
try {
writeEnvelopeIntoFile(srcMail, envelopeFile);
} catch (IOException e) {
if (envelopeFile.exists() && !envelopeFile.delete()) {
logger.error("Writing to the envelope file failed, the "
+ "file exists, and it could not be deleted: "
+ envelopeFile);
} else {
if (contentFile.exists() && !contentFile.delete()) {
logger.error("Deleting message content file of "
+ mailName
+ " failed after "
+ "message envelope could not be written into file. "
+ "The mail transaction will be rejected, "
+ "and the mail will never be processed. "
+ "Message content file remains in the queue "
+ "directory, please delete it manually.");
} else {
releaseMailName(mailName);
}
}
throw new QueueStorageException(e, EnhancedStatus.MAIL_SYSTEM_FULL);
}
logger.debug("Mail was saved to store: {}, {}", srcMail, dir);
return mailName;
}
private synchronized MailName allocateMailName(Mail srcMail)
throws QueueStorageException {
if (!initialized)
throw new IllegalStateException();
if (srcMail.scheduleDate == null)
throw new IllegalArgumentException(
"Schedule date must have been set before");
if (mailNames.size() >= maxSize)
throw new QueueStorageException(
"Store is full",
EnhancedStatus.TRANSIENT_SYSTEM_NOT_ACCEPTING_NETWORK_MESSAGES);
// find a free sequence number, within the scheduleDate
long scheduleDate = srcMail.scheduleDate.getTime();
MailName nameForTheNextTimePoint = new MailName(scheduleDate + 1, 0);
MailName previousMail = mailNames.lower(nameForTheNextTimePoint);
int sequenceNumber;
if (previousMail == null || previousMail.scheduleDate < scheduleDate) {
// so there is no mail on the same scheduleDate
sequenceNumber = 0;
} else {
// there is mail on the same time point
sequenceNumber = previousMail.sequenceNumber + 1;
}
MailName mailName = new MailName(scheduleDate, sequenceNumber);
mailNames.add(mailName);
return mailName;
}
private synchronized void releaseMailName(MailName mailName) {
boolean found = mailNames.remove(mailName);
if (!found) {
logger.error("Mail name could not been found in the set of "
+ "allocated names, this should not happen.");
}
}
private File contentFileForName(MailName mailName) {
return new File(dir, mailName.contentFileName());
}
private File envelopeFileForName(MailName mailName) {
return new File(dir, mailName.envelopeFileName());
}
private void writeMessageContentIntoFile(MailData mailData,
File messageContentFile) throws IOException {
FileOutputStream out = new FileOutputStream(messageContentFile);
try {
mailData.writeTo(out);
} finally {
out.close();
}
}
private void writeEnvelopeIntoFile(Mail srcMail, File propertiesFile)
throws IOException {
Properties props =
new MailEnvelopePersister().saveToProperties(srcMail);
Writer out =
new OutputStreamWriter(new FileOutputStream(propertiesFile),
"UTF-8");
try {
props.store(out, null);
} finally {
out.close();
}
}
public Mail read(MailName mailName) throws QueueStorageException {
try {
File propertiesFile = new File(dir, mailName.envelopeFileName());
InputStream propertiesStream = new FileInputStream(propertiesFile);
DataProperties properties = new DataProperties();
try {
properties
.load(new InputStreamReader(propertiesStream, "UTF-8"));
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e); // impossible
} finally {
propertiesStream.close();
}
Mail mail =
new MailEnvelopePersister().readFromProperties(properties);
File mailDataFile = new File(dir, mailName.contentFileName());
mail.mailData = new FileMailData(mailDataFile);
return mail;
} catch (IOException e) {
throw new QueueStorageException(e,
EnhancedStatus.TRANSIENT_LOCAL_ERROR_IN_PROCESSING);
}
}
public void moveToErrorDir(MailName mailName) throws QueueStorageException {
File envelopeFile = new File(dir, mailName.envelopeFileName());
File mailDataFile = new File(dir, mailName.contentFileName());
try {
File errorDir = new File(dir, "error");
errorDir.mkdir();
if (envelopeFile.exists()) {
File envelopeTargetFile =
new File(errorDir, mailName.envelopeFileName());
StreamCopier.copyFile(envelopeFile, envelopeTargetFile);
logger.info("Envelope file has been successfully copied into "
+ "the error directory: " + envelopeFile);
} else {
logger.error("Envelope file could not be copied into the error "
+ "directory, because it does not exist: "
+ envelopeFile);
}
if (mailDataFile.exists()) {
File mailDataTargetFile =
new File(errorDir, mailName.contentFileName());
StreamCopier.copyFile(mailDataFile, mailDataTargetFile);
logger.info("Mail data file has been successfully moved into "
+ "the error directory: " + envelopeFile);
} else {
logger.error("Mail data file could not be moved to the error "
+ "directory, because it does not exist: "
+ mailDataFile);
}
envelopeFile.delete();
mailDataFile.delete();
} catch (IOException e) {
throw new QueueStorageException(e, EnhancedStatus.MAIL_SYSTEM_FULL);
}
if (!envelopeFile.exists() && !mailDataFile.exists()) {
releaseMailName(mailName);
} else {
throw new QueueStorageException(
"Mail name cannot be released, because either the "
+ "envelope or the mail data file still exists: "
+ mailName,
EnhancedStatus.TRANSIENT_LOCAL_ERROR_IN_PROCESSING);
}
}
public void delete(MailName mailName) throws QueueStorageException {
try {
File envelopeFile = new File(dir, mailName.envelopeFileName());
boolean fSuccess = envelopeFile.delete();
if (!fSuccess)
throw new IOException("Cannot delete envelope file "
+ envelopeFile);
File mailDataFile = new File(dir, mailName.contentFileName());
fSuccess = mailDataFile.delete();
if (!fSuccess)
throw new IOException("Cannot delete mail data file "
+ mailDataFile);
releaseMailName(mailName);
} catch (IOException e) {
throw new QueueStorageException(e,
EnhancedStatus.TRANSIENT_LOCAL_ERROR_IN_PROCESSING);
}
}
@Override
public String toString() {
return "FileDirStore [dir=" + dir + "]";
}
/**
* @x.category GETSET
*/
public void setDir(String dir) {
this.dir = new File(dir);
}
/**
* @x.category GETSET
*/
public void setMaxSize(int maxSize) {
this.maxSize = maxSize;
}
}