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/*
* Copyright (c) 2014-2015 VMware, Inc. All Rights Reserved.
*
* 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.vmware.xenon.dns.services;
import java.net.URI;
import java.util.EnumSet;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import com.vmware.xenon.common.Operation;
import com.vmware.xenon.common.ServiceDocument;
import com.vmware.xenon.common.ServiceDocumentDescription;
import com.vmware.xenon.common.ServiceDocumentDescription.PropertyDescription;
import com.vmware.xenon.common.ServiceDocumentDescription.PropertyIndexingOption;
import com.vmware.xenon.common.StatefulService;
import com.vmware.xenon.common.UriUtils;
import com.vmware.xenon.common.Utils;
/**
* Service that represents DNS records
*/
public class DNSService extends StatefulService {
public static class DNSServiceState extends ServiceDocument {
public static final String FIELD_NAME_SERVICE_NAME = "serviceName";
public static final String FIELD_NAME_SERVICE_TAGS = "tags";
public enum ServiceStatus {
AVAILABLE, UNKNOWN, UNAVAILABLE
}
@UsageOption(option = ServiceDocumentDescription.PropertyUsageOption.AUTO_MERGE_IF_NOT_NULL)
public String serviceLink;
@UsageOption(option = ServiceDocumentDescription.PropertyUsageOption.ID)
public String serviceName;
@UsageOption(option = ServiceDocumentDescription.PropertyUsageOption.OPTIONAL)
public Set tags;
@UsageOption(option = ServiceDocumentDescription.PropertyUsageOption.AUTO_MERGE_IF_NOT_NULL)
public String healthCheckLink;
@UsageOption(option = ServiceDocumentDescription.PropertyUsageOption.AUTO_MERGE_IF_NOT_NULL)
public Long healthCheckIntervalSeconds;
@UsageOption(option = ServiceDocumentDescription.PropertyUsageOption.AUTO_MERGE_IF_NOT_NULL)
public String hostName;
@UsageOption(option = ServiceDocumentDescription.PropertyUsageOption.AUTO_MERGE_IF_NOT_NULL)
public Set nodeReferences;
@UsageOption(option = ServiceDocumentDescription.PropertyUsageOption.AUTO_MERGE_IF_NOT_NULL)
public ServiceStatus serviceStatus;
}
public DNSService() {
super(DNSServiceState.class);
super.toggleOption(ServiceOption.PERSISTENCE, true);
super.toggleOption(ServiceOption.REPLICATION, true);
super.toggleOption(ServiceOption.OWNER_SELECTION, true);
}
@Override
public void handleStart(Operation start) {
DNSServiceState dnsServiceState = start.getBody(DNSServiceState.class);
if (dnsServiceState.healthCheckLink != null
&& dnsServiceState.healthCheckIntervalSeconds > 0) {
super.toggleOption(ServiceOption.PERIODIC_MAINTENANCE, true);
setMaintenanceIntervalMicros(
TimeUnit.SECONDS.toMicros(dnsServiceState.healthCheckIntervalSeconds));
}
start.complete();
}
public void sendSelfPatch(DNSServiceState newState) {
Operation patch = Operation.createPatch(getUri())
.setBody(newState);
sendRequest(patch);
}
@Override
public void handleMaintenance(Operation post) {
Operation.CompletionHandler completionHandler = (o, e) -> {
if (e != null) {
post.fail(e);
}
DNSServiceState currentState = o.getBody(DNSServiceState.class);
URI[] nodeReferenceArray = currentState.nodeReferences.toArray(new URI[currentState.nodeReferences.size()]);
performAvailabilityCheck(post, nodeReferenceArray, currentState.healthCheckLink, 0);
};
sendRequest(Operation.createGet(getUri()).setCompletion(completionHandler));
}
private void performAvailabilityCheck(Operation maint, URI[] nodeReferences, String healthCheckLink, int nodeIndex) {
/*
The maintenance call is used to validate service availability
based on Health Check Link provided and the interval.
1) Attempt a GET on the first nodeReference + healthCheckLink.
2) If health check returns true, mark the service available.
3) If health check returns false, attempt the same on next nodeReference + healthCheckLink.
4) If we exhausted all the nodeReferences mark the service unavailable.
*/
Operation.CompletionHandler completionHandler = (on, en) -> {
DNSServiceState.ServiceStatus serviceStatus = DNSServiceState.ServiceStatus.UNKNOWN;
if (en == null) {
try {
serviceStatus = on.getBody(
DNSServiceState.ServiceStatus.class);
} catch (Exception e2) {
if (on.getStatusCode() == Operation.STATUS_CODE_OK) {
serviceStatus = DNSServiceState.ServiceStatus.AVAILABLE;
} else if (on.getStatusCode() == Operation.STATUS_CODE_UNAVAILABLE) {
serviceStatus = DNSServiceState.ServiceStatus.UNAVAILABLE;
} else {
serviceStatus = DNSServiceState.ServiceStatus.UNKNOWN;
}
}
if (serviceStatus == DNSServiceState.ServiceStatus.AVAILABLE) {
populateServiceAvailability(maint, serviceStatus);
} else {
performAvailabilityCheck(maint, nodeReferences, healthCheckLink, nodeIndex + 1);
}
} else {
performAvailabilityCheck(maint, nodeReferences, healthCheckLink, nodeIndex + 1);
}
};
if (nodeIndex >= nodeReferences.length) {
populateServiceAvailability(maint, DNSServiceState.ServiceStatus.UNAVAILABLE);
} else {
Operation healthCheckOp = Operation
.createGet(UriUtils.extendUri(nodeReferences[nodeIndex], healthCheckLink))
.setCompletion(completionHandler);
this.sendRequest(healthCheckOp);
}
}
private void populateServiceAvailability(Operation maint,
DNSServiceState.ServiceStatus serviceStatus) {
DNSServiceState dnsServiceState = new DNSServiceState();
dnsServiceState.serviceStatus = serviceStatus;
sendSelfPatch(dnsServiceState);
maint.complete();
}
@Override
public void handlePatch(Operation patch) {
DNSServiceState currentState = getState(patch);
DNSServiceState body = patch.getBody(DNSServiceState.class);
boolean modified;
modified = Utils.mergeWithState(getDocumentTemplate().documentDescription, currentState, body);
modified = mergeCollectionState(currentState,body,modified);
if (modified) {
// Make sure we turn on next maintenance if a valid check url interval is provided.
if (currentState.healthCheckLink != null && currentState.healthCheckIntervalSeconds > 0) {
super.toggleOption(ServiceOption.PERIODIC_MAINTENANCE, true);
setMaintenanceIntervalMicros(
TimeUnit.SECONDS.toMicros(currentState.healthCheckIntervalSeconds));
} else {
super.toggleOption(ServiceOption.PERIODIC_MAINTENANCE, false);
}
patch.setBody(currentState);
}
patch.complete();
}
@Override
public void handlePut(Operation put) {
if (!put.hasBody()) {
put.fail(new IllegalArgumentException("body is required"));
return;
}
DNSServiceState newState = put.getBody(DNSServiceState.class);
DNSServiceState currentState = getState(put);
boolean merged = false;
if (!validate(currentState, newState)) {
put.setStatusCode(Operation.STATUS_CODE_CONFLICT);
} else {
merged = mergeCollectionState(currentState, newState, merged);
if (merged) {
setState(put,currentState);
}
}
put.complete();
}
private boolean mergeCollectionState(DNSServiceState currentState, DNSServiceState newState, boolean modified) {
// merge tags
if (newState.tags != null && !newState.tags.isEmpty()) {
modified = currentState.tags.addAll(newState.tags);
}
// merge service references
if (newState.nodeReferences != null && !newState.nodeReferences.isEmpty()) {
modified = currentState.nodeReferences.addAll(newState.nodeReferences) || modified;
}
return modified;
}
private boolean validate(DNSServiceState currentState, DNSServiceState newState) {
if (!currentState.serviceName.equals(newState.serviceName)) {
return false;
}
if (!currentState.serviceLink.equals(newState.serviceLink)) {
return false;
}
if (currentState.nodeReferences.size() == 0) {
return false;
}
if (!currentState.healthCheckLink.equals(newState.healthCheckLink)) {
return false;
}
if (!currentState.healthCheckIntervalSeconds.equals(newState.healthCheckIntervalSeconds)) {
return false;
}
return true;
}
@Override
public ServiceDocument getDocumentTemplate() {
ServiceDocument d = super.getDocumentTemplate();
PropertyDescription pdTags = d.documentDescription.propertyDescriptions
.get(DNSServiceState.FIELD_NAME_SERVICE_TAGS);
pdTags.indexingOptions = EnumSet.of(PropertyIndexingOption.EXPAND);
return d;
}
}
