Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/5114#discussion_r154873317
--- Diff:
flink-mesos/src/main/java/org/apache/flink/mesos/util/MesosResourceAllocation.java
---
@@ -0,0 +1,197 @@
+/*
+ * 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.flink.mesos.util;
+
+import org.apache.mesos.Protos;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Set;
+
+import static org.apache.flink.mesos.Utils.print;
+
+/**
+ * An allocation of resources on a particular host from one or more Mesos
offers, to be portioned out to tasks.
+ *
+ * <p>This class assumes that the resources were offered <b>without</b>
the {@code RESERVATION_REFINEMENT} capability,
+ * as detailed in the "Resource Format" section of the Mesos protocol
definition.
+ *
+ * <p>This class is not thread-safe.
+ */
+public class MesosResourceAllocation {
+
+ protected static final Logger LOG =
LoggerFactory.getLogger(MesosResourceAllocation.class);
+
+ static final double EPSILON = 1e-5;
+ static final String UNRESERVED_ROLE = "*";
+
+ private final List<Protos.Resource> resources;
+
+ /**
+ * Creates an allocation of resources for tasks to take.
+ *
+ * @param resources the resources to add to the allocation.
+ */
+ public MesosResourceAllocation(Collection<Protos.Resource> resources) {
+ this.resources = new ArrayList<>(resources);
+
+ // sort the resources to prefer reserved resources
+ this.resources.sort(Comparator.comparing(r ->
UNRESERVED_ROLE.equals(r.getRole())));
+ }
+
+ /**
+ * Gets the remaining resources.
+ */
+ public List<Protos.Resource> getRemaining() {
+ return Collections.unmodifiableList(resources);
+ }
+
+ /**
+ * Takes some amount of scalar resources (e.g. cpus, mem).
+ *
+ * @param amount the (approximate) amount to take from the available
quantity.
+ * @param roles the roles to accept
+ */
+ public List<Protos.Resource> takeScalar(String resourceName, double
amount, Set<String> roles) {
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Allocating {} {}", amount, resourceName);
+ }
+
+ List<Protos.Resource> result = new ArrayList<>(1);
+ for (ListIterator<Protos.Resource> i =
resources.listIterator(); i.hasNext();) {
+ if (amount <= EPSILON) {
+ break;
+ }
+
+ // take from next available scalar resource that is
unreserved or reserved for an applicable role
+ Protos.Resource available = i.next();
+ if (!resourceName.equals(available.getName()) ||
!available.hasScalar()) {
+ continue;
+ }
+ if (!UNRESERVED_ROLE.equals(available.getRole()) &&
!roles.contains(available.getRole())) {
+ continue;
+ }
+
+ double amountToTake =
Math.min(available.getScalar().getValue(), amount);
+ Protos.Resource taken =
available.toBuilder().setScalar(Protos.Value.Scalar.newBuilder().setValue(amountToTake)).build();
+ amount -= amountToTake;
+ result.add(taken);
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Taking {} from {}", amountToTake,
print(available));
+ }
+
+ // keep remaining amount (if any)
+ double remaining = available.getScalar().getValue() -
taken.getScalar().getValue();
+ if (remaining > EPSILON) {
+
i.set(available.toBuilder().setScalar(Protos.Value.Scalar.newBuilder().setValue(remaining)).build());
+ }
+ else {
+ i.remove();
+ }
+ }
+
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Allocated: {}, unsatisfied: {}",
print(result), amount);
+ }
+ return result;
+ }
+
+ /**
+ * Takes some amount of range resources (e.g. ports).
+ *
+ * @param amount the number of values to take from the available
range(s).
+ * @param roles the roles to accept
+ */
+ public List<Protos.Resource> takeRanges(String resourceName, int
amount, Set<String> roles) {
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Allocating {} {}", amount, resourceName);
+ }
+
+ List<Protos.Resource> result = new ArrayList<>(1);
+ for (ListIterator<Protos.Resource> i =
resources.listIterator(); i.hasNext();) {
+ if (amount <= 0) {
+ break;
+ }
+
+ // take from next available range resource that is
unreserved or reserved for an applicable role
+ Protos.Resource available = i.next();
+ if (!resourceName.equals(available.getName()) ||
!available.hasRanges()) {
+ continue;
+ }
+ if (!UNRESERVED_ROLE.equals(available.getRole()) &&
!roles.contains(available.getRole())) {
+ continue;
+ }
+
+ List<Protos.Value.Range> takenRanges = new
ArrayList<>();
+ List<Protos.Value.Range> remainingRanges = new
ArrayList<>(available.getRanges().getRangeList());
+ for (ListIterator<Protos.Value.Range> j =
remainingRanges.listIterator(); j.hasNext();) {
+ if (amount <= 0) {
+ break;
+ }
+
+ // take from next available range (note: ranges
are inclusive)
+ Protos.Value.Range availableRange = j.next();
+ long amountToTake =
Math.min(availableRange.getEnd() - availableRange.getBegin() + 1, amount);
+ Protos.Value.Range takenRange =
availableRange.toBuilder().setEnd(availableRange.getBegin() + amountToTake -
1).build();
+ amount -= amountToTake;
+ takenRanges.add(takenRange);
+
+ // keep remaining range (if any)
+ long remaining = availableRange.getEnd() -
takenRange.getEnd();
+ if (remaining > 0) {
+
j.set(availableRange.toBuilder().setBegin(availableRange.getEnd() - remaining +
1).build());
--- End diff --
I think this expression could be simplified to `takenRange.getEnd() + 1`.
---
