Examples with Degrader com.linkedin.util.degrader.Degrader used on opensource projects

Example 1 with Degrader

use of com.linkedin.util.degrader.Degrader in project rest.li by linkedin.

the class DegraderLoadBalancerStrategyV3 method getTrackerClient.

@Override
public TrackerClient getTrackerClient(Request request, RequestContext requestContext, long clusterGenerationId, int partitionId, Map<URI, TrackerClient> trackerClients, boolean shouldForceUpdate) {
    debug(_log, "getTrackerClient with generation id ", clusterGenerationId, " partition id: ", partitionId, " on tracker clients: ", trackerClients);
    if (trackerClients == null || trackerClients.size() == 0) {
        warn(_log, "getTrackerClient called with null/empty trackerClients, so returning null");
        return null;
    }
    List<DegraderTrackerClient> degraderTrackerClients = castToDegraderTrackerClients(trackerClients);
    // only one thread will be allowed to enter updatePartitionState for any partition
    TimingContextUtil.markTiming(requestContext, TIMING_KEY);
    checkUpdatePartitionState(clusterGenerationId, partitionId, degraderTrackerClients, shouldForceUpdate);
    TimingContextUtil.markTiming(requestContext, TIMING_KEY);
    Ring<URI> ring = _state.getRing(partitionId);
    URI targetHostUri = KeyMapper.TargetHostHints.getRequestContextTargetHost(requestContext);
    Set<URI> excludedUris = ExcludedHostHints.getRequestContextExcludedHosts(requestContext);
    if (excludedUris == null) {
        excludedUris = new HashSet<>();
    }
    // no valid target host header was found in the request
    DegraderTrackerClient client;
    if (targetHostUri == null) {
        client = findValidClientFromRing(request, ring, degraderTrackerClients, excludedUris, requestContext);
    } else {
        debug(_log, "Degrader honoring target host header in request, skipping hashing.  URI: ", targetHostUri);
        client = searchClientFromUri(targetHostUri, degraderTrackerClients);
        if (client == null) {
            warn(_log, "No client found for ", targetHostUri, ". Target host specified is no longer part of cluster");
        } else {
            // if this flag is set to be true, that means affinity routing is preferred but backup requests are still acceptable
            Boolean otherHostAcceptable = KeyMapper.TargetHostHints.getRequestContextOtherHostAcceptable(requestContext);
            if (otherHostAcceptable != null && otherHostAcceptable) {
                ExcludedHostHints.addRequestContextExcludedHost(requestContext, targetHostUri);
            }
        }
    }
    if (client == null) {
        return null;
    }
    // Decides whether to drop the call
    Degrader degrader = client.getDegrader(partitionId);
    if (degrader.checkDrop()) {
        warn(_log, "client's degrader is dropping call for: ", client);
        return null;
    }
    debug(_log, "returning client: ", client);
    // Decides whether to degrade call at the transport layer
    if (degrader.checkPreemptiveTimeout()) {
        DegraderControl degraderControl = client.getDegraderControl(partitionId);
        requestContext.putLocalAttr(R2Constants.PREEMPTIVE_TIMEOUT_RATE, degraderControl.getPreemptiveRequestTimeoutRate());
    }
    return client;
}