@Override
public void accept(final IGangliaMessage msg) {
if (msg == null) return;
/*
* true iff the message is from this host.
*
* Note: A message from this host could be from either an embedded
* ganglia service (such as ourselves) or from gmond or even gmetad
* (if we are running on the same host as gmetad).
*
* It is Ok to accept metric value updates from ourselves, and this
* makes it possible to listen to a gmond instance on the same host.
* However, the receipt of a metric value MUST NOT cause us to send
* out a new metric value record.
*/
if (msg.isMetricRequest()) {
/*
* Metadata request.
*/
if (isQuietPeriod()) {
/*
* Ignore requests during the quiet period.
*
* TODO Review the quite period behavior. Is this correct?
*/
return;
}
/*
* Lookup the metric value for *this* host.
*/
final TimestampMetricValue tmv = gangliaState.getMetric(hostName, msg.getMetricName());
if (tmv != null && tmv.getTimestamp() != 0L) {
/*
* If the requested metric is known on this host then we
* reset it now. The next time we sample that metric it will
* have a timestamp of ZERO (0) and will be sent out to all
* listeners. Since the timestamp is ZERO (0) (rather than a
* valid timestamp at which the metric was last sent), the
* metadata record will also be sent out.
*/
tmv.resetTimestamp();
if (log.isInfoEnabled()) log.info("Reset metric timestamp: " + msg.toString());
}
} else if (msg.isMetricMetadata()) {
/*
* Handle metadata message.
*
* TODO Allow a pattern for metrics that we will accept. Do not
* store the declaration unless it satisfies that pattern.
*/
if (gangliaState.putIfAbsent((IGangliaMetadataMessage) msg) == null) {
if (log.isInfoEnabled()) log.info("declared by host: " + msg.toString());
}
} else if (msg.isMetricValue()) {
/*
* TODO Allow a pattern for metrics that we will accept. Do not
* store the declaration unless it satisfies that pattern.
*/
if (gangliaState.getMetadata(msg.getMetricName()) == null) {
/*
* Request the metadata for the metric.
*
* Note: We will not accept the metric record into our
* internal state until we have received a metadata record
* for that metric.
*/
if (log.isDebugEnabled()) log.debug("No metadata for metric: " + msg.getMetricName());
sendMessage(new GangliaRequestMessage(hostName, msg.getMetricName(), false /* spoof */));
return;
}
/*
* Update the counters for the appropriate host.
*
* Note: At this point we have verified that we have a metadata
* declaration on hand for this metric so we can go ahead and
* store the metric value in our internal state.
*/
final IGangliaMetricMessage m2 = (IGangliaMetricMessage) msg;
final TimestampMetricValue tmv =
gangliaState.getMetric(msg.getHostName(), msg.getMetricName());
// Guaranteed non-null since metadata decl exists for metric.
assert tmv != null;
/*
* Update the value.
*
* Note: The return value is ignored. Since the metric was
* received over the wire we ignore the age of the metric rather
* than using the metric age to trigger a send of the metric
* value. (I.e., avoid re-sending received metrics.)
*/
tmv.setValue(m2.getValue());
if (log.isDebugEnabled()) log.debug("Updated value: " + msg);
} else {
log.error("Unknown message type: " + msg);
}
}
