com.hazelcast.azure.AzureDiscoveryStrategyFactory Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2024, Hazelcast, 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.hazelcast.azure;
import com.hazelcast.config.properties.PropertyDefinition;
import com.hazelcast.logging.ILogger;
import com.hazelcast.logging.Logger;
import com.hazelcast.spi.discovery.DiscoveryNode;
import com.hazelcast.spi.discovery.DiscoveryStrategy;
import com.hazelcast.spi.discovery.DiscoveryStrategyFactory;
import com.hazelcast.spi.utils.RestClient;
import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
/**
* Factory class which returns {@link AzureDiscoveryStrategy} to Discovery SPI
*/
public class AzureDiscoveryStrategyFactory implements DiscoveryStrategyFactory {
private static final ILogger LOGGER = Logger.getLogger(AzureDiscoveryStrategyFactory.class);
@Override
public Class getDiscoveryStrategyType() {
return AzureDiscoveryStrategy.class;
}
@Override
public DiscoveryStrategy newDiscoveryStrategy(DiscoveryNode node, ILogger logger,
Map properties) {
return new AzureDiscoveryStrategy(properties);
}
@Override
public Collection getConfigurationProperties() {
List result = new ArrayList<>();
for (AzureProperties property : AzureProperties.values()) {
result.add(property.getDefinition());
}
return result;
}
/**
* Checks if Hazelcast is running on Azure.
*
* To check if Hazelcast is running on Azure, we first check whether "internal.cloudapp.net" is present in the file
* "/etc/resolv.conf". Such an approach is not officially documented but seems like a good enough heuristic to detect an
* Azure Compute VM Instance. Since it's not the official method, we still need to make an API call to a local, non-routable
* address http://169.254.169.254/metadata/instance.
*
* @return true if running on Azure Instance
* @see Azure
* Instance Metadata API
*/
@Override
public boolean isAutoDetectionApplicable() {
return azureDnsServerConfigured() && azureInstanceMetadataAvailable();
}
private static boolean azureDnsServerConfigured() {
return readFileContents("/etc/resolv.conf").contains("internal.cloudapp.net");
}
static String readFileContents(String fileName) {
try {
File file = new File(fileName);
return Files.readString(file.toPath(), StandardCharsets.UTF_8);
} catch (IOException e) {
throw new RuntimeException("Could not get " + fileName, e);
}
}
private static boolean azureInstanceMetadataAvailable() {
return isEndpointAvailable("http://169.254.169.254/metadata/instance?api-version=2020-06-01");
}
static boolean isEndpointAvailable(String url) {
return !RestClient.create(url, 1)
.withRequestTimeoutSeconds(1)
.withRetries(1)
.withHeader("Metadata", "True")
.get()
.getBody()
.isEmpty();
}
@Override
public DiscoveryStrategyLevel discoveryStrategyLevel() {
return DiscoveryStrategyLevel.CLOUD_VM;
}
}