com.predic8.membrane.core.kubernetes.BeanCache Maven / Gradle / Ivy

/* Copyright 2022 predic8 GmbH, www.predic8.com

   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.predic8.membrane.core.kubernetes;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
import com.predic8.membrane.core.Router;
import com.predic8.membrane.core.config.spring.K8sHelperGeneratorAutoGenerated;
import com.predic8.membrane.core.config.spring.k8s.Envelope;
import com.predic8.membrane.core.config.spring.k8s.YamlLoader;
import com.predic8.membrane.core.kubernetes.client.WatchAction;
import com.predic8.membrane.core.rules.Rule;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.StringReader;
import java.util.*;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;

public class BeanCache implements BeanRegistry {
    private static final Logger LOG = LoggerFactory.getLogger(KubernetesWatcher.class);
    private final Router router;
    private final ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
    private ConcurrentHashMap uuidMap = new ConcurrentHashMap<>();
    private ArrayBlockingQueue changeEvents = new ArrayBlockingQueue<>(1000);
    private Thread thread;

    public BeanCache(Router router) {
        this.router = router;
    }

    public void start() {
        thread = new Thread(() -> {
            while (!Thread.interrupted()) {
                try {
                    BeanDefinition beanDefinition = changeEvents.take();
                    handle(beanDefinition);
                } catch (InterruptedException e) {
                    break;
                }
            }

        });
        thread.start();
    }

    public void stop() {
        if (thread != null)
            thread.interrupt();
    }

    public Envelope define(Map map) throws IOException {
        String s = mapper.writeValueAsString(map).substring(4);
        if (LOG.isDebugEnabled())
            LOG.debug("defining bean: " + s);
        YamlLoader y = new YamlLoader();
        Envelope envelope = y.load(new StringReader(s), this);
        System.err.println("SUCCESS.");
        return envelope;
    }

    /**
     * May be called from multiple threads.
     */
    public void handle(WatchAction action, Map m) throws IOException {
        changeEvents.add(new BeanDefinition(action, m));
    }

    // uid -> bean definition
    Map bds = new HashMap<>();
    Set uidsToActivate = new HashSet<>();

    void handle(BeanDefinition bd) {
        if (bd.getAction() == WatchAction.DELETED)
            bds.remove(bd.getUid());
        else
            bds.put(bd.getUid(), bd);

        if (bd.isRule())
            uidsToActivate.add(bd.getUid());

        if (changeEvents.size() == 0)
            activationRun();
    }

    public void activationRun() {
        System.err.println("---");
        Set uidsToRemove = new HashSet<>();
        for (String uid : uidsToActivate) {
            BeanDefinition bd = bds.get(uid);
            try {
                Envelope envelope = define(bd.getMap());
                bd.setEnvelope(envelope);
                Rule newRule = (Rule) envelope.getSpec();
                try {
                    newRule.setName(bd.getName());
                    newRule.init(router);
                } catch (Exception e) {
                    throw new RuntimeException("Could not init rule.", e);
                }

                Rule oldRule = null;
                if (bd.getAction() == WatchAction.MODIFIED || bd.getAction() == WatchAction.DELETED)
                    oldRule = (Rule) uuidMap.get(bd.getUid());

                if (bd.getAction() == WatchAction.ADDED)
                    router.add(newRule);
                else if (bd.getAction() == WatchAction.DELETED)
                    router.getRuleManager().removeRule(oldRule);
                else if (bd.getAction() == WatchAction.MODIFIED)
                    router.getRuleManager().replaceRule(oldRule, newRule);

                if (bd.getAction() == WatchAction.ADDED || bd.getAction() == WatchAction.MODIFIED)
                    uuidMap.put(bd.getUid(), newRule);
                if (bd.getAction() == WatchAction.DELETED)
                    uuidMap.remove(bd.getUid());
                uidsToRemove.add(bd.getUid());
            } catch (Throwable e) {
                LOG.error("Could not handle " + bd.getAction() + " " + bd.getNamespace() + "/" + bd.getName(), e);
            }
        }
        for (String uid : uidsToRemove)
            uidsToActivate.remove(uid);
    }

    @Override
    public Object resolveReference(String url) {
        Optional obd = bds.values().stream().filter(bd -> bd.getName().equals(url)).findFirst();
        if (obd.isPresent()) {
            BeanDefinition bd = obd.get();
            Envelope envelope = null;
            if (bd.getEnvelope() != null)
                envelope = bd.getEnvelope();
            if (envelope == null) {
                try {
                    envelope = define(bd.getMap());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
                if (!"prototype".equals(bd.getScope()))
                    bd.setEnvelope(envelope);
            }
            Object spec = envelope.getSpec();
            if (spec instanceof Bean)
                return ((Bean) spec).getBean();
            return spec;
        }
        throw new RuntimeException("Reference " + url + " not found");
    }
}