com.sap.cloud.security.ams.factory.AmsPolicyDecisionPointFactory Maven / Gradle / Ivy

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Client Library for integrating Jakarta EE applications with SAP Authorization Management Service (AMS)
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/************************************************************************
* © 2019-2023 SAP SE or an SAP affiliate company. All rights reserved. *
************************************************************************/
package com.sap.cloud.security.ams.factory;

import com.sap.cloud.security.ams.dcl.client.pdp.PolicyDecisionPoint;
import com.sap.cloud.security.ams.dcl.client.pdp.PolicyDecisionPointFactory;
import com.sap.cloud.security.ams.logging.PolicyEvaluationSlf4jLogger;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

/**
 * This shall be called with {@code PolicyDecisionPoint.create(DEFAULT)}. It is
 * registered as service to
 * {@code META-INF.services/com.sap.cloud.security.ams.dcl.client.pdp.PolicyDecisionPointFactory}.
 */
public class AmsPolicyDecisionPointFactory extends PolicyDecisionPointFactory {
	/**
	 * Choose this {@code PolicyDecisionPoint} kind, in case you like to leverage
	 * the policy engine that is available on the url provided with {@code ADC_URL}
	 * system environment variable. This is the default on Cloud Foundry
	 * environment, when running using the buildpack.
	 */
	public static final String DEFAULT = "default";
	public static final String ENV_ADC_URL = "ADC_URL";

	private static final Logger LOGGER = LoggerFactory.getLogger(AmsPolicyDecisionPointFactory.class);

	private static final String DCL_RUNTIME_CLIENT = "client:opa";
	private static final Map CACHE = new ConcurrentHashMap<>();
	private static final int PRIORITY = 100;

	@Override
	protected PolicyDecisionPoint tryCreate(String kind, Object[] arguments) {
		if (DEFAULT.equalsIgnoreCase(kind)) {
			Object[] extArguments = Arrays.copyOf(arguments, arguments.length + 2);
			extArguments[arguments.length] = "url";
			extArguments[arguments.length + 1] = getUrl();
			return getOrCreate(DCL_RUNTIME_CLIENT, extArguments);
		}
		return null; // can not handle this kind
	}

	@Override
	protected int getPriority() {
		return PRIORITY;
	}

	PolicyDecisionPoint getOrCreate(String kind, Object[] arguments) {
		String key = kind + Arrays.toString(arguments);
		PolicyDecisionPoint pdp = CACHE.get(key);
		if (Objects.isNull(pdp) || pdp.isClosed()) {
			synchronized (CACHE) {
				pdp = CACHE.get(key);
				if (Objects.isNull(pdp) || pdp.isClosed()) {
					LOGGER.debug("instantiate PolicyDecisionPoint for kind {} and args {}.", DCL_RUNTIME_CLIENT,
							arguments);
					pdp = PolicyDecisionPoint.create(kind, arguments);
					pdp.registerListener(PolicyEvaluationSlf4jLogger.getInstance());
					CACHE.put(key, pdp);
				}
			}
		}
		return CACHE.get(key);
	}

	URL getUrl() {
		String adcUrl = readUrlSystemEnv();
		if (Objects.isNull(adcUrl)) {
			LOGGER.debug("ADC_URL System environment variable was null, using default value");
			adcUrl = "http://localhost:8181";
		}
		try {
			return new URL(adcUrl);
		} catch (MalformedURLException urlException) {
			LOGGER.error("PolicyDecisionPoint instantiation failed due to erroneous ADC_URL {}.", adcUrl);
			throw new IllegalStateException(
					"PolicyDecisionPoint instantiation failed due to erroneous ADC_URL: " + adcUrl, urlException);
		}
	}

	String readUrlSystemEnv() {
		return System.getenv(ENV_ADC_URL);
	}
}