com.nike.riposte.server.config.impl.AppInfoImpl Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of riposte-spi Show documentation
Riposte module riposte-spi
There is a newer version: 0.20.0
package com.nike.riposte.server.config.impl;

import com.nike.riposte.server.config.AppInfo;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * Simple basic implementation of {@link AppInfo}. Also includes a few static factory methods for attempting to infer
 * app ID / environment, and for creating "local" instances that aren't part of a datacenter.
 *
 * @author Nic Munroe
 */
@SuppressWarnings("WeakerAccess")
public class AppInfoImpl implements AppInfo {

    private static final Logger logger = LoggerFactory.getLogger(AppInfoImpl.class);
    // NOTE: Can't be final - would break the ability to do exception unit testing
    private static LocalHostnameGetter LOCAL_HOSTNAME_GETTER = new LocalHostnameGetter();

    public final String appId;
    public final String environment;
    public final String dataCenter;
    public final String instanceId;

    // Intentionally protected - this is here for deserialization support only.
    protected AppInfoImpl() {
        this(null, null, null, null);
    }

    public AppInfoImpl(String appId, String environment, String dataCenter, String instanceId) {
        this.appId = appId;
        this.environment = environment;
        this.dataCenter = dataCenter;
        this.instanceId = instanceId;
    }

    @Override
    public String appId() {
        return appId;
    }

    @Override
    public String environment() {
        return environment;
    }

    @Override
    public String dataCenter() {
        return dataCenter;
    }

    @Override
    public String instanceId() {
        return instanceId;
    }

    /**
     * @return An {@link AppInfoImpl} instance with the {@link #appId} pulled from {@link #detectAppId()}, {@link
     * #environment} set to "local", {@link #dataCenter} set to "local", and {@link #instanceId} pulled from the local
     * box hostname using {@code InetAddress.getLocalHost().getHostName()} (or {@link AppInfo#UNKNOWN_VALUE} if that
     * threw an error). If you know that {@link #detectAppId()} won't work for your app you'll want to determine the app
     * ID a different way and call {@link #createLocalInstance(String)} instead, because if {@link #detectAppId()}
     * returns null then this method will throw an {@link IllegalStateException}.
     */
    public static AppInfoImpl createLocalInstance() {
        String appId = detectAppId();
        if (appId == null) {
            throw new IllegalStateException("Unable to autodetect app ID. Please call createLocalInstance(String) "
                                            + "instead and pass the app ID manually");
        }

        return createLocalInstance(appId);
    }

    /**
     * Uses {@link #LOCAL_HOSTNAME_GETTER} to retrieve the local hostname.
     */
    protected static String getLocalHostName() throws UnknownHostException {
        return LOCAL_HOSTNAME_GETTER.getLocalHostname();
    }

    /**
     * @param appId
     *     The app ID to use.
     *
     * @return An {@link AppInfoImpl} instance with the {@link #appId} set to the given argument, {@link #environment}
     * set to "local", {@link #dataCenter} set to "local", and {@link #instanceId} pulled from the local box hostname
     * using {@code InetAddress.getLocalHost().getHostName()} (or {@link AppInfo#UNKNOWN_VALUE} if that threw an
     * error).
     */
    public static AppInfoImpl createLocalInstance(String appId) {
        String environment = "local";
        String datacenter = "local";

        String instanceId = null;
        try {
            instanceId = getLocalHostName();
        }
        catch (UnknownHostException e) {
            logger.error("Unable to extract localhost address", e);
        }

        if (instanceId == null)
            instanceId = UNKNOWN_VALUE;

        return new AppInfoImpl(appId, environment, datacenter, instanceId);
    }

    /**
     * @return The appId if it was found in the known set of system properties that represent app ID, or null if it
     * could not be found. It searches for a non-null System property using {@link System#getProperty(String)} and
     * returns the first non-null one it finds. The search is done in the following order:  @appId
     * archaius.deployment.applicationId
 eureka.name
  NOTE: A return value of null does not
     * necessarily mean there is no appId, it just means this code doesn't know how to extract it.
     */
    public static String detectAppId() {
        // Attempt to get it from @appId or archaius.deployment.applicationId System properties first - used by Archaius
        //      or any Riposte app that follows the Archaius conventions.
        String appId = System.getProperty("@appId");
        if (appId != null)
            return appId;

        appId = System.getProperty("archaius.deployment.applicationId");
        if (appId != null)
            return appId;

        // Try eureka.name next.
        appId = System.getProperty("eureka.name");
        if (appId != null)
            return appId;

        // Unable to detect. Return null.
        return null;
    }

    /**
     * @return The environment value if it was found in the known set of system properties that represent environment
     * (local, test, prod, etc), or null if it could not be found. It searches for a non-null System property using
     * {@link System#getProperty(String)} and returns the first non-null one it finds. The search is done in the
     * following order:  @environment
 archaius.deployment.environment
  NOTE: A return value
     * of null does not necessarily mean there is no environment, it just means this code doesn't know how to extract
     * it.
     */
    public static String detectEnvironment() {
        // Attempt to get it from @environment or archaius.deployment.environment System properties first - used by
        //      Archaius or any Riposte app that follows the Archaius conventions.
        String environment = System.getProperty("@environment");
        if (environment != null)
            return environment;

        environment = System.getProperty("archaius.deployment.environment");
        if (environment != null)
            return environment;

        // Unable to detect. Return null.
        return null;
    }

    /**
     * Simple class that retrieves the local hostname using {@code InetAddress.getLocalHost().getHostName()}. This is
     * here as a separate class so that it can be tested and overridden easily in unit tests.
     */
    protected static class LocalHostnameGetter {

        public String getLocalHostname() throws UnknownHostException {
            return InetAddress.getLocalHost().getHostName();
        }
    }

}