software.amazon.awssdk.services.applicationautoscaling.endpoints.internal.PartitionFn Maven / Gradle / Ivy

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The AWS Java SDK for AWS Application Auto Scaling module holds the client classes that are used for communicating with AWS Application Auto Scaling service.
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/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with
 * the License. A copy of the License is located at
 * 
 * http://aws.amazon.com/apache2.0
 * 
 * or in the "license" file accompanying this file. This file 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 software.amazon.awssdk.services.applicationautoscaling.endpoints.internal;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Supplier;
import java.util.regex.Pattern;
import software.amazon.awssdk.annotations.SdkInternalApi;
import software.amazon.awssdk.utils.MapUtils;

@SdkInternalApi
public class PartitionFn extends SingleArgFn {
    public static final String ID = "aws.partition";

    public static final Identifier NAME = Identifier.of("name");
    public static final Identifier DNS_SUFFIX = Identifier.of("dnsSuffix");
    public static final Identifier DUAL_STACK_DNS_SUFFIX = Identifier.of("dualStackDnsSuffix");
    public static final Identifier SUPPORTS_FIPS = Identifier.of("supportsFIPS");
    public static final Identifier SUPPORTS_DUAL_STACK = Identifier.of("supportsDualStack");
    public static final Identifier INFERRED = Identifier.of("inferred");

    private final LazyValue partitionData = LazyValue. builder()
            .initializer(this::loadPartitionData).build();

    private final LazyValue awsPartition = LazyValue. builder().initializer(this::findAwsPartition).build();

    public PartitionFn(FnNode node) {
        super(node);
    }

    public static PartitionFn ofExprs(Expr expr) {
        return new PartitionFn(FnNode.ofExprs(ID, expr));
    }

    @Override
    public  T acceptFnVisitor(FnVisitor visitor) {
        return visitor.visitPartition(this);
    }

    public static PartitionFn fromParam(Parameter param) {
        return PartitionFn.ofExprs(param.expr());
    }

    @Override
    public Value evalArg(Value arg) {
        String regionName = arg.expectString();

        PartitionData data = partitionData.value();

        Partition matchedPartition;
        boolean inferred = false;

        // Known region
        matchedPartition = data.regionMap.get(regionName);
        if (matchedPartition == null) {
            // try matching on region name pattern
            for (Partition p : data.partitions) {
                Pattern regex = Pattern.compile(p.regionRegex());
                if (regex.matcher(regionName).matches()) {
                    matchedPartition = p;
                    inferred = true;
                    break;
                }
            }
        }

        // Couldn't find the region by name or pattern matching. Fallback to 'aws' partition.
        if (matchedPartition == null) {
            matchedPartition = awsPartition.value();
        }

        Outputs matchedOutputs = matchedPartition.outputs();
        return Value.fromRecord(MapUtils.of(NAME, Value.fromStr(matchedPartition.id()), DNS_SUFFIX,
                Value.fromStr(matchedOutputs.dnsSuffix()), DUAL_STACK_DNS_SUFFIX,
                Value.fromStr(matchedOutputs.dualStackDnsSuffix()), SUPPORTS_FIPS, Value.fromBool(matchedOutputs.supportsFips()),
                SUPPORTS_DUAL_STACK, Value.fromBool(matchedOutputs.supportsDualStack()), INFERRED, Value.fromBool(inferred)));
    }

    private PartitionData loadPartitionData() {
        PartitionDataProvider provider = new DefaultPartitionDataProvider();

        // TODO: support custom partitions.json
        Partitions partitions = provider.loadPartitions();

        PartitionData partitionData = new PartitionData();

        partitions.partitions().forEach(part -> {
            partitionData.partitions.add(part);
            part.regions().forEach((name, override) -> {
                partitionData.regionMap.put(name, part);
            });
        });

        return partitionData;
    }

    private Partition findAwsPartition() {
        return partitionData.value().partitions.stream().filter(p -> p.id().equalsIgnoreCase("aws")).findFirst().orElse(null);
    }

    private static class PartitionData {
        private final List partitions = new ArrayList<>();
        private final Map regionMap = new HashMap<>();
    }

    private static final class LazyValue {
        private final Supplier initializer;
        private T value;
        private boolean initialized;

        private LazyValue(Builder builder) {
            this.initializer = builder.initializer;
        }

        public T value() {
            if (!initialized) {
                value = initializer.get();
                initialized = true;
            }
            return value;
        }

        public static  Builder builder() {
            return new Builder<>();
        }

        public static class Builder {
            private Supplier initializer;

            public Builder initializer(Supplier initializer) {
                this.initializer = initializer;
                return this;
            }

            public LazyValue build() {
                return new LazyValue<>(this);
            }
        }
    }

}