JsonMessageHandler1_0.java

/*
 * Copyright 2017 ThoughtWorks, Inc.
 *
 * 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.thoughtworks.go.plugin.access.configrepo;


import com.google.gson.GsonBuilder;
import com.thoughtworks.go.plugin.access.configrepo.codec.GsonCodec;
import com.thoughtworks.go.plugin.access.configrepo.contract.*;
import com.thoughtworks.go.plugin.access.configrepo.messages.*;
import org.apache.log4j.Logger;

import java.util.Collection;

public class JsonMessageHandler1_0 implements JsonMessageHandler {

    private static final Logger LOGGER = Logger.getLogger(JsonMessageHandler1_0.class);
    private static final int CURRENT_CONTRACT_VERSION = 1;

    private final GsonCodec codec;

    public JsonMessageHandler1_0(){
        codec = new GsonCodec();
    }

    @Override
    public String requestMessageForParseDirectory(String destinationFolder, Collection<CRConfigurationProperty> configurations) {
        ParseDirectoryMessage requestMessage = prepareMessage_1(destinationFolder, configurations);
        return codec.getGson().toJson(requestMessage);
    }

    private ParseDirectoryMessage prepareMessage_1(String destinationFolder, Collection<CRConfigurationProperty> configurations) {
        ParseDirectoryMessage requestMessage = new ParseDirectoryMessage(destinationFolder);
        for(CRConfigurationProperty conf : configurations)
        {
            requestMessage.addConfiguration(conf.getKey(),conf.getValue(),conf.getEncryptedValue());
        }
        return requestMessage;
    }
    class ResponseScratch {
        public Integer target_version;
    }
    private ResponseScratch parseResponseForMigration(String responseBody) {
        return new GsonBuilder().create().fromJson(responseBody, ResponseScratch.class);
    }

    @Override
    public CRParseResult responseMessageForParseDirectory(String responseBody) {
        ErrorCollection errors = new ErrorCollection();
        try {
            ResponseScratch responseMap = parseResponseForMigration(responseBody);
            ParseDirectoryResponseMessage parseDirectoryResponseMessage;

            if(responseMap.target_version == null)
            {
                errors.addError("Plugin response message","missing 'target_version' field");
                return new CRParseResult(errors);
            }
            else {
                int version = responseMap.target_version;

                while (version < CURRENT_CONTRACT_VERSION) {
                    migrate(responseBody, version);
                    version++;
                }
                // after migration, json should match contract
                parseDirectoryResponseMessage = codec.getGson().fromJson(responseBody, ParseDirectoryResponseMessage.class);
                parseDirectoryResponseMessage.validateResponse(errors);

                errors.addErrors(parseDirectoryResponseMessage.getPluginErrors());

                return new CRParseResult(parseDirectoryResponseMessage.getEnvironments(), parseDirectoryResponseMessage.getPipelines(), errors);
            }
        }
        catch (Exception ex)
        {
            StringBuilder builder = new StringBuilder();
            builder.append("Unexpected error when handling plugin response").append('\n');
            builder.append(ex);
            // "location" of error is runtime. This is what user will see in config repo errors list.
            errors.addError("runtime",builder.toString());
            return new CRParseResult(errors);
        }
    }

    private void migrate(String responseBody, int targetVersion) {
        if(targetVersion > 1)
            throw new RuntimeException(String.format("Migration to %s is not supported",targetVersion));
    }
}