@Override
public void run() {
for (Map.Entry<String, ConfigFileInfo> entry : watchedFileMap.entrySet()) {
String filePath = entry.getKey();
ConfigFileInfo configFileInfo = entry.getValue();
try {
File file = new File(filePath);
long lastModified = file.lastModified();
Preconditions.checkArgument(lastModified > 0L);
if (lastModified != configFileInfo.lastModifiedTimestampMillis) {
configFileInfo.lastModifiedTimestampMillis = lastModified;
ByteSource byteSource = Files.asByteSource(file);
HashCode newContentHash = byteSource.hash(HASH_FUNCTION);
if (!newContentHash.equals(configFileInfo.contentHash)) {
configFileInfo.contentHash = newContentHash;
LOG.info("File {} was modified at {}, notifying watchers.", filePath, lastModified);
byte[] newContents = byteSource.read();
for (Function<byte[], Void> watchers : configFileInfo.changeWatchers) {
try {
watchers.apply(newContents);
} catch (Exception e) {
LOG.error(
"Exception in watcher callback for {}, ignoring. New file contents were: {}",
filePath,
new String(newContents, Charsets.UTF_8),
e);
}
}
} else {
LOG.info(
"File {} was modified at {} but content hash is unchanged.",
filePath,
lastModified);
}
} else {
LOG.debug("File {} not modified since {}", filePath, lastModified);
}
} catch (Exception e) {
// We catch and log exceptions related to the update of any specific file, but
// move on so others aren't affected. Issues can happen for example if the watcher
// races with an external file replace operation; in that case, the next run should
// pick up the update.
// TODO: Consider adding a metric to track this so we can alert on failures.
LOG.error("Config update check failed for {}", filePath, e);
}
}
}
public static void main(String[] args)
throws IOException, SAXException, ParserConfigurationException {
RemoteFileChecker remoteFileChecker = new RemoteFileChecker();
ContentRemover contentRemover = new ContentRemover();
while (true) {
ConfigFileInfo configFileInfo = new ConfigurationFileParser().parseConfigFile();
boolean remoteFileExists =
remoteFileChecker.checkIfRemoteFileExists(configFileInfo.getRemoteUrl());
if (remoteFileExists) {
contentRemover.remove(configFileInfo);
try {
Thread.sleep(ONE_HOUR);
} catch (InterruptedException e) {
}
}
}
}
