SpawnProcessForEachMachine.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.provisionr.core.activities;

import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import java.util.List;
import org.activiti.engine.ProcessEngine;
import org.activiti.engine.delegate.DelegateExecution;
import org.activiti.engine.delegate.JavaDelegate;
import org.activiti.engine.runtime.ProcessInstance;
import org.apache.provisionr.api.pool.Machine;
import org.apache.provisionr.api.pool.Pool;
import org.apache.provisionr.core.CoreConstants;
import org.apache.provisionr.core.CoreProcessVariables;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Create an Activiti process for each machine and store the process IDs
 */
public class SpawnProcessForEachMachine implements JavaDelegate {

    private static final Logger LOG = LoggerFactory.getLogger(SpawnProcessForEachMachine.class);

    /**
     * Name of the process variable that stores a {@link org.apache.provisionr.api.pool.Machine Machine} object.
     * Used inside the process to connect to that machine.
     */
    private static final String MACHINE = "machine";

    private final ProcessEngine processEngine;
    private final String processKey;
    private final String type;
    private final String resultVariable;

    public SpawnProcessForEachMachine(
        ProcessEngine processEngine, String processKey, String type, String resultVariable
    ) {
        this.processEngine = checkNotNull(processEngine, "processEngine is null");
        this.processKey = checkNotNull(processKey, "processKey is null");
        this.type = checkNotNull(type, "type is null");
        this.resultVariable = checkNotNull(resultVariable, "resultVariable is null");
    }

    @Override
    public void execute(DelegateExecution execution) {
        final Pool pool = (Pool) execution.getVariable(CoreProcessVariables.POOL);
        checkNotNull(pool, "Expecting to find a pool description as process variable");

        @SuppressWarnings("unchecked")
        List<Machine> machines = (List<Machine>) execution.getVariable(CoreProcessVariables.MACHINES);
        checkNotNull(machines, "Expecting to find the list of machines as process variable");

        final String poolBusinessKey = String.class.cast(execution.getVariable(CoreProcessVariables.POOL_BUSINESS_KEY));
        checkNotNull(poolBusinessKey, "No way to link sub-processes to master process, poolBusinessKey is null");

        /* Authenticate as kermit to make the process visible in the Explorer UI */
        processEngine.getIdentityService().setAuthenticatedUserId(CoreConstants.ACTIVITI_EXPLORER_DEFAULT_USER);

        List<String> processIds = Lists.newArrayList();
        for (Machine machine : machines) {
            final String perMachineProcessBusinessKey = String.format("%s-%s-%s",
                execution.getProcessBusinessKey(), type, machine.getExternalId());

            ProcessInstance perMachineProcess = processEngine.getRuntimeService().startProcessInstanceByKey(
                processKey, perMachineProcessBusinessKey,
                ImmutableMap.<String, Object>of(CoreProcessVariables.POOL, pool,
                    CoreProcessVariables.POOL_BUSINESS_KEY, poolBusinessKey,
                    CoreProcessVariables.IS_CACHED_IMAGE, pool.getSoftware().isCachedImage(),
                    MACHINE, machine));

            LOG.info("Started background '" + type + "' process {} ({}) for machine {}",
                new Object[]{perMachineProcessBusinessKey, perMachineProcess.getId(), machine.getExternalId()});
            processIds.add(perMachineProcess.getId());
        }

        LOG.info("Saving process IDs {} as {}", processIds, resultVariable);
        execution.setVariable(resultVariable, processIds);
    }
}