Github user apsaltis commented on a diff in the pull request:
https://github.com/apache/nifi/pull/1177#discussion_r87223668
--- Diff:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/GetTCP.java
---
@@ -0,0 +1,668 @@
+/*
+ * 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.standard;
+
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.SideEffectFree;
+import org.apache.nifi.annotation.behavior.SupportsBatching;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.annotation.lifecycle.OnScheduled;
+import org.apache.nifi.annotation.lifecycle.OnStopped;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.ValidationContext;
+import org.apache.nifi.components.ValidationResult;
+import org.apache.nifi.components.Validator;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.processor.util.StandardValidators;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.SocketAddress;
+import java.net.SocketTimeoutException;
+import java.net.StandardSocketOptions;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.channels.AlreadyConnectedException;
+import java.nio.channels.ConnectionPendingException;
+import java.nio.channels.SocketChannel;
+import java.nio.channels.UnresolvedAddressException;
+import java.nio.channels.UnsupportedAddressTypeException;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.StandardCharsets;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+@SupportsBatching
+@SideEffectFree
+@Tags({"get", "fetch", "poll", "tcp", "ingest", "source", "input"})
+@InputRequirement(InputRequirement.Requirement.INPUT_FORBIDDEN)
+@CapabilityDescription("Connects over TCP to the provided server. When
receiving data this will writes either the" +
+ " full receive buffer or messages based on demarcator to the
content of a FlowFile. ")
+public class GetTCP extends AbstractProcessor {
+
+ private static final Validator ENDPOINT_VALIDATOR = new Validator() {
+ @Override
+ public ValidationResult validate(final String subject, final
String value, final ValidationContext context) {
+ if (null == value || value.isEmpty()) {
+ return new
ValidationResult.Builder().subject(subject).input(value).valid(false).explanation(subject
+ " cannot be empty").build();
+ }
+ //The format should be <host>:<port>{,<host>:<port>}
+ //first split on ,
+ final String[] hostPortPairs = value.split(",");
+ boolean validHostPortPairs = true;
+ String reason = "";
+ String offendingSubject = subject;
+
+ if(0 == hostPortPairs.length){
+ return new
ValidationResult.Builder().subject(subject).input(value).valid(false).explanation(offendingSubject
+ " cannot be empty").build();
+ }
+ for (final String hostPortPair : hostPortPairs) {
+ offendingSubject = hostPortPair;
+ //split pair
+ if (hostPortPair.isEmpty()) {
+ validHostPortPairs = false;
+ reason = "endpoint is empty";
+ break;
+ }
+ if (!hostPortPair.contains(":")) {
+ validHostPortPairs = false;
+ reason = "endpoint pair does not contain valid
delimiter";
+ break;
+ }
+ final String[] parts = hostPortPair.split(":");
+
+ if (1 == parts.length) {
+ validHostPortPairs = false;
+ reason = "could not determine the port";
+ break;
+ } else {
+ try {
+ final int intVal = Integer.parseInt(parts[1]);
+
+ if (intVal <= 0) {
+ reason = "not a positive value";
+ validHostPortPairs = false;
+ break;
+ }
+ } catch (final NumberFormatException e) {
+ reason = "not a valid integer";
+ validHostPortPairs = false;
+ break;
+ }
+ }
+ //if we already have a bad pair then exit now.
+ if (!validHostPortPairs) {
+ break;
+ }
+ }
+ return new
ValidationResult.Builder().subject(offendingSubject).input(value).explanation(reason).valid(validHostPortPairs).build();
+ }
+ };
+
+ public static final PropertyDescriptor ENDPOINT_LIST = new
PropertyDescriptor
+ .Builder().name("Endpoint List")
+ .description("A comma delimited list of the servers to connect
to. The format should be " +
+ "<server_address>:<port>. Only one server will be
connected to at a time, the others " +
+ "will be used as fail overs.")
+ .required(true)
+ .addValidator(ENDPOINT_VALIDATOR)
+ .build();
+
+ public static final PropertyDescriptor FAILOVER_ENDPOINT = new
PropertyDescriptor
+ .Builder().name("Failover Endpoint")
+ .description("A failover server to connect to if one of the
main ones is unreachable after the connection " +
+ "attempt count. The format should be
<server_address>:<port>.")
--- End diff --
There are actually two different use case in play. That first is that there
is a single server you want to connect to and get data from and if that fails
then you want to connect to a backup server. I can see how the endpoint list
maybe used to satisfy this. However, there is a second use case which may not
be apparent. In the second case the endpoint list forms a logical grouping of
servers to connect to simultaneously and receive information. Thus, they are
all active and do not serve as a backup. In this case the failover server is
used when connectivity to one of the endpoint servers fails.
I am totally open to other ways of handling the two use cases if this is
confusing/misleading/or not as clean as it could be.
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