transport/gcp-transport/src/main/java/org/apache/airavata/mft/transport/gcp/GCSReceiver.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.airavata.mft.transport.gcp;

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.services.storage.Storage;
import com.google.api.services.storage.StorageScopes;
import org.apache.airavata.mft.core.ConnectorContext;
import org.apache.airavata.mft.core.api.Connector;
import org.apache.airavata.mft.resource.client.ResourceServiceClient;
import org.apache.airavata.mft.resource.client.ResourceServiceClientBuilder;
import org.apache.airavata.mft.resource.stubs.gcs.resource.GCSResource;
import org.apache.airavata.mft.resource.stubs.gcs.resource.GCSResourceGetRequest;
import org.apache.airavata.mft.secret.client.SecretServiceClient;
import org.apache.airavata.mft.secret.service.GCSSecret;
import org.apache.airavata.mft.secret.service.GCSSecretGetRequest;
import org.apache.airavata.mft.secret.service.SecretServiceGrpc;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.Collection;


public class GCSReceiver implements Connector {

    private static final Logger logger = LoggerFactory.getLogger(GCSReceiver.class);

    private GCSResource gcsResource;
    private Storage storage;

    @Override
    public void init(String resourceId, String credentialToken, String resourceServiceHost, int resourceServicePort, String secretServiceHost, int secretServicePort) throws Exception {
        ResourceServiceClient resourceClient = ResourceServiceClientBuilder.buildClient(resourceServiceHost, resourceServicePort);
        this.gcsResource = resourceClient.gcs().getGCSResource(GCSResourceGetRequest.newBuilder().setResourceId(resourceId).build());

        SecretServiceGrpc.SecretServiceBlockingStub secretClient = SecretServiceClient.buildClient(secretServiceHost, secretServicePort);
        GCSSecret gcsSecret = secretClient.getGCSSecret(GCSSecretGetRequest.newBuilder().setSecretId(credentialToken).build());
        HttpTransport transport = GoogleNetHttpTransport.newTrustedTransport();
        JsonFactory jsonFactory = new JacksonFactory();
        String jsonString = gcsSecret.getCredentialsJson();
        GoogleCredential credential = GoogleCredential.fromStream(new ByteArrayInputStream(jsonString.getBytes(StandardCharsets.UTF_8)));
        if (credential.createScopedRequired()) {
            Collection<String> scopes = StorageScopes.all();
            credential = credential.createScoped(scopes);
        }
        storage = new Storage.Builder(transport, jsonFactory, credential).build();
    }

    @Override
    public void destroy() {

    }

    @Override
    public void startStream(ConnectorContext context) throws Exception {
        logger.info("Starting GCS Receiver stream for transfer {}", context.getTransferId());

        InputStream inputStream = storage.objects().get(this.gcsResource.getBucketName(), this.gcsResource.getResourcePath()).executeMediaAsInputStream();
        OutputStream os = context.getStreamBuffer().getOutputStream();
        int read;
        long bytes = 0;
        long fileSize = context.getMetadata().getResourceSize();
        byte[] buf = new byte[1024];
        while (true) {
            int bufSize = 0;

            if (buf.length < fileSize) {
                bufSize = buf.length;
            } else {
                bufSize = (int) fileSize;
            }
            bufSize = inputStream.read(buf, 0, bufSize);

            if (bufSize < 0) {
                break;
            }

            os.write(buf, 0, bufSize);
            os.flush();

            fileSize -= bufSize;
            if (fileSize == 0L)
                break;
        }

        os.close();

        logger.info("Completed GCS Receiver stream for transfer {}", context.getTransferId());
    }
}