nifi-nar-bundles/nifi-gcp-bundle/nifi-gcp-processors/src/main/java/org/apache/nifi/processors/gcp/storage/AbstractGCSProcessor.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.nifi.processors.gcp.storage;

import com.google.api.gax.retrying.RetrySettings;
import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.BaseServiceException;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import com.google.common.collect.ImmutableList;
import org.apache.nifi.components.ConfigVerificationResult;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.components.ValidationContext;
import org.apache.nifi.components.ValidationResult;
import org.apache.nifi.logging.ComponentLog;
import org.apache.nifi.processor.ProcessContext;
import org.apache.nifi.processor.Relationship;
import org.apache.nifi.processor.VerifiableProcessor;
import org.apache.nifi.processors.gcp.AbstractGCPProcessor;
import org.apache.nifi.processors.gcp.ProxyAwareTransportFactory;
import org.apache.nifi.proxy.ProxyConfiguration;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Base class for creating processors which connect to Google Cloud Storage.
 *
 * Every GCS processor operation requires a bucket, whether it's reading or writing from said bucket.
 */
public abstract class AbstractGCSProcessor extends AbstractGCPProcessor<Storage, StorageOptions> implements VerifiableProcessor {
    public static final Relationship REL_SUCCESS =
            new Relationship.Builder().name("success")
                    .description("FlowFiles are routed to this relationship after a successful Google Cloud Storage operation.")
                    .build();
    public static final Relationship REL_FAILURE =
            new Relationship.Builder().name("failure")
                    .description("FlowFiles are routed to this relationship if the Google Cloud Storage operation fails.")
                    .build();

    public static final Set<Relationship> relationships = Collections.unmodifiableSet(
            new HashSet<>(Arrays.asList(REL_SUCCESS, REL_FAILURE)));

    @Override
    public Set<Relationship> getRelationships() {
        return relationships;
    }

    @Override
    public List<PropertyDescriptor> getSupportedPropertyDescriptors() {
        return ImmutableList.<PropertyDescriptor>builder()
                .addAll(super.getSupportedPropertyDescriptors())
                .build();
    }

    @Override
    public List<ConfigVerificationResult> verify(final ProcessContext context, final ComponentLog verificationLogger, final Map<String, String> attributes) {
        final List<ConfigVerificationResult> results = new ArrayList<>(verifyCloudService(context, verificationLogger, attributes));
        final Storage storage = getCloudService(context);
        if (storage != null) {
            try {
                final String bucket = getBucketName(context, attributes);
                final List<String> requiredPermissions = getRequiredPermissions();
                if (storage.testIamPermissions(bucket, requiredPermissions).size() >= requiredPermissions.size()) {
                    results.add(new ConfigVerificationResult.Builder()
                            .verificationStepName("Test IAM Permissions")
                            .outcome(ConfigVerificationResult.Outcome.SUCCESSFUL)
                            .explanation(String.format("Verified Bucket [%s] exists and the configured user has the correct permissions.", bucket))
                            .build());
                } else {
                    results.add(new ConfigVerificationResult.Builder()
                            .verificationStepName("Test IAM Permissions")
                            .outcome(ConfigVerificationResult.Outcome.FAILED)
                            .explanation(String.format("The configured user does not have the correct permissions on Bucket [%s].", bucket))
                            .build());
                }
            } catch (final BaseServiceException e) {
                verificationLogger.error("The configured user appears to have the correct permissions, but the following error was encountered", e);
                results.add(new ConfigVerificationResult.Builder()
                        .verificationStepName("Test IAM Permissions")
                        .outcome(ConfigVerificationResult.Outcome.FAILED)
                        .explanation(String.format("The configured user appears to have the correct permissions, but the following error was encountered: " + e.getMessage()))
                        .build());
            }
        }
        return results;
    }

    @Override
    protected final Collection<ValidationResult> customValidate(ValidationContext validationContext) {
        final Collection<ValidationResult> results = super.customValidate(validationContext);
        ProxyConfiguration.validateProxySpec(validationContext, results, ProxyAwareTransportFactory.PROXY_SPECS);
        customValidate(validationContext, results);
        return results;
    }

    /**
     * If sub-classes needs to implement any custom validation, override this method then add validation result to the results.
     */
    protected void customValidate(ValidationContext validationContext, Collection<ValidationResult> results) {
    }

    /**
     * @return The list of GCP permissions required for the processor
     */
    protected abstract List<String> getRequiredPermissions();

    protected String getBucketName(final ProcessContext context, final Map<String, String> attributes) {
        return context.getProperty("gcs-bucket").evaluateAttributeExpressions(attributes).getValue();
    }

    @Override
    protected StorageOptions getServiceOptions(ProcessContext context, GoogleCredentials credentials) {
        final String projectId = context.getProperty(PROJECT_ID).evaluateAttributeExpressions().getValue();
        final Integer retryCount = context.getProperty(RETRY_COUNT).asInteger();

        StorageOptions.Builder storageOptionsBuilder = StorageOptions.newBuilder()
                .setCredentials(credentials)
                .setRetrySettings(RetrySettings.newBuilder()
                        .setMaxAttempts(retryCount)
                        .build());

        if (projectId != null && !projectId.isEmpty()) {
            storageOptionsBuilder.setProjectId(projectId);
        }

        return  storageOptionsBuilder.setTransportOptions(getTransportOptions(context)).build();
    }
}