Github user joewitt commented on a diff in the pull request:
https://github.com/apache/nifi/pull/1482#discussion_r100466820
--- Diff:
nifi-nar-bundles/nifi-gcp-bundle/nifi-gcp-processors/src/main/java/org/apache/nifi/processors/gcp/AbstractGCPProcessor.java
---
@@ -0,0 +1,118 @@
+/*
+ * 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;
+
+import com.google.auth.oauth2.GoogleCredentials;
+import com.google.cloud.HttpServiceOptions;
+import com.google.cloud.Service;
+import com.google.common.collect.ImmutableList;
+import org.apache.nifi.annotation.lifecycle.OnScheduled;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.util.StandardValidators;
+import
org.apache.nifi.processors.gcp.credentials.service.GCPCredentialsService;
+
+import java.util.List;
+
+/**
+ * Abstract base class for gcp processors.
+ *
+ */
+public abstract class AbstractGCPProcessor<
+ CloudService extends Service<CloudServiceOptions>,
+ CloudServiceRpc,
+ CloudServiceOptions extends HttpServiceOptions<CloudService,
CloudServiceRpc, CloudServiceOptions>> extends AbstractProcessor {
+
+ public static final PropertyDescriptor PROJECT_ID = new
PropertyDescriptor
+ .Builder().name("gcp-project-id")
+ .displayName("Project ID")
+ .description("Google Cloud Project ID")
+ .expressionLanguageSupported(true)
+ .required(true)
+ .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
+ .build();
+
+ public static final PropertyDescriptor RETRY_COUNT = new
PropertyDescriptor
+ .Builder().name("gcp-retry-count")
+ .displayName("Number of retries")
+ .description("How many retry attempts should be made before
routing to the failure relationship.")
+ .defaultValue("6")
+ .expressionLanguageSupported(true)
+ .required(true)
+ .addValidator(StandardValidators.INTEGER_VALIDATOR)
+ .build();
+
+ /**
+ * Links to the {@link GCPCredentialsService} which provides
credentials for this particular processor.
+ */
+ public static final PropertyDescriptor
GCP_CREDENTIALS_PROVIDER_SERVICE = new PropertyDescriptor.Builder()
+ .name("gcp-credentials-provider-service")
+ .name("GCP Credentials Provider Service")
+ .description("The Controller Service used to obtain Google
Cloud Platform credentials.")
+ .required(true)
+ .identifiesControllerService(GCPCredentialsService.class)
+ .build();
+
+
+ protected volatile CloudService cloudService;
+
+ protected CloudService getCloudService() {
+ return cloudService;
+ }
+
+ @Override
+ public List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+ return ImmutableList.of(
+ GCP_CREDENTIALS_PROVIDER_SERVICE,
+ PROJECT_ID,
+ RETRY_COUNT
+ );
+ }
+
+
+ /**
+ * Retrieve credentials from the {@link GCPCredentialsService}
attached to this processor.
+ * @param context the process context provided on scheduling the
processor.
+ * @return GoogleCredentials for the processor to access.
+ * @see <a
href="https://developers.google.com/api-client-library/java/google-api-java-client/reference/1.20.0/com/google/api/client/googleapis/auth/oauth2/GoogleCredential";>AuthCredentials</a>
+ */
+ private GoogleCredentials getGoogleCredentials(final ProcessContext
context) {
+ final GCPCredentialsService gcpCredentialsService =
+
context.getProperty(GCP_CREDENTIALS_PROVIDER_SERVICE).asControllerService(GCPCredentialsService.class);
+ return gcpCredentialsService.getGoogleCredentials();
+ }
+
+ /**
+ * Assigns the cloud service client on scheduling.
+ * @param context the process context provided on scheduling the
processor.
+ */
+ @OnScheduled
+ public void onScheduled(ProcessContext context) {
--- End diff --
It isn't clear to me just yet but as a thing to consider.. This
'cloudService' instance being set means this cloud service object must be
thread safe should these processors have more than one thread and if this
service is like a connection then it may be better to lazily init during
onTrigger calls so that it can be recovered if the connection drops. Open
connections can be killed during onUnscheduled.
What I'm suggesting here might not matter if this object isn't what it
seems in just scanning through the code. I checked the google api for
'getService()' to see if I could better understand what it was and it wasnt
revealing.
In any even this is a really substantive PR with a lot of well thought out
areas and attention to details like LICENSE/NOTICE so big thanks to you.
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