com.datastax.oss.driver.internal.core.loadbalancing.helper.DefaultNodeDistanceEvaluatorHelper Maven / Gradle / Ivy
/*
* Copyright DataStax, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.datastax.oss.driver.internal.core.loadbalancing.helper;
import com.datastax.oss.driver.api.core.config.DefaultDriverOption;
import com.datastax.oss.driver.api.core.config.DriverExecutionProfile;
import com.datastax.oss.driver.api.core.loadbalancing.NodeDistance;
import com.datastax.oss.driver.api.core.loadbalancing.NodeDistanceEvaluator;
import com.datastax.oss.driver.api.core.metadata.Node;
import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
import com.datastax.oss.driver.internal.core.util.Reflection;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.util.Map;
import java.util.UUID;
import java.util.function.Predicate;
import net.jcip.annotations.ThreadSafe;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A {@link NodeDistanceEvaluatorHelper} implementation that fetches the user-supplied evaluator, if
* any, from the programmatic configuration API, or else, from the driver configuration. If no
* user-supplied evaluator can be retrieved, a dummy evaluator will be used which always evaluates
* null distances.
*/
@ThreadSafe
public class DefaultNodeDistanceEvaluatorHelper implements NodeDistanceEvaluatorHelper {
private static final Logger LOG =
LoggerFactory.getLogger(DefaultNodeDistanceEvaluatorHelper.class);
@NonNull protected final InternalDriverContext context;
@NonNull protected final DriverExecutionProfile profile;
@NonNull protected final String logPrefix;
public DefaultNodeDistanceEvaluatorHelper(
@NonNull InternalDriverContext context,
@NonNull DriverExecutionProfile profile,
@NonNull String logPrefix) {
this.context = context;
this.profile = profile;
this.logPrefix = logPrefix;
}
@NonNull
@Override
public NodeDistanceEvaluator createNodeDistanceEvaluator(
@Nullable String localDc, @NonNull Map nodes) {
NodeDistanceEvaluator nodeDistanceEvaluatorFromConfig = nodeDistanceEvaluatorFromConfig();
return (node, dc) -> {
NodeDistance distance = nodeDistanceEvaluatorFromConfig.evaluateDistance(node, dc);
if (distance != null) {
LOG.debug("[{}] Evaluator assigned distance {} to node {}", logPrefix, distance, node);
} else {
LOG.debug("[{}] Evaluator did not assign a distance to node {}", logPrefix, node);
}
return distance;
};
}
@NonNull
protected NodeDistanceEvaluator nodeDistanceEvaluatorFromConfig() {
NodeDistanceEvaluator evaluator = context.getNodeDistanceEvaluator(profile.getName());
if (evaluator != null) {
LOG.debug("[{}] Node distance evaluator set programmatically", logPrefix);
} else {
evaluator =
Reflection.buildFromConfig(
context,
profile.getName(),
DefaultDriverOption.LOAD_BALANCING_DISTANCE_EVALUATOR_CLASS,
NodeDistanceEvaluator.class)
.orElse(null);
if (evaluator != null) {
LOG.debug("[{}] Node distance evaluator set from configuration", logPrefix);
} else {
@SuppressWarnings({"unchecked", "deprecation"})
Predicate nodeFilterFromConfig =
Reflection.buildFromConfig(
context,
profile.getName(),
DefaultDriverOption.LOAD_BALANCING_FILTER_CLASS,
Predicate.class)
.orElse(null);
if (nodeFilterFromConfig != null) {
evaluator = new NodeFilterToDistanceEvaluatorAdapter(nodeFilterFromConfig);
LOG.debug(
"[{}] Node distance evaluator set from deprecated node filter configuration",
logPrefix);
}
}
}
if (evaluator == null) {
evaluator = PASS_THROUGH_DISTANCE_EVALUATOR;
}
return evaluator;
}
}