[feat] PIP-188 Support blue-green migration

[heesung-sn]

Master Issue: apache/pulsar#16551

Motivation

Support blue-green migration pip-188 for cpp client

Modifications

• added blue-green client logic
• register the producer instance in the producers map before sending produce creation command. This is required since broker could send topic migration command in the middle of creating the producer.

Verifying this change

• Make sure that the change passes the CI checks.
  Updated the exisiting extensibleLB test to cover the migration logic.

Documentation

• doc-required
  (Your PR needs to update docs and you will update later)

• doc-not-needed
  (Please explain why)

• doc
  (Your PR contains doc changes)

• doc-complete
  (Docs have been already added)

[BewareMyPower]

Added the 3.5.0 milestone according to https://lists.apache.org/thread/fr4pv2p8yxhxcg2wc9sqdfzm89y8cnox

[BewareMyPower]

I changed the IO threads to 8 for ExtensibleLoadManagerTest and found segmentation fault when closing the client.

diff --git a/tests/extensibleLM/ExtensibleLoadManagerTest.cc b/tests/extensibleLM/ExtensibleLoadManagerTest.cc
index 7567569..f4e2c81 100644
--- a/tests/extensibleLM/ExtensibleLoadManagerTest.cc
+++ b/tests/extensibleLM/ExtensibleLoadManagerTest.cc
@@ -70,7 +70,9 @@ TEST(ExtensibleLoadManagerTest, testPubSubWhileUnloading) {
         return res == 204 || res == 409;
     }));
 
-    Client client{"pulsar://localhost:6650"};
+    ClientConfiguration conf;
+    conf.setIOThreads(8);
+    Client client{"pulsar://localhost:6650", conf};
     Producer producer;
     ProducerConfiguration producerConfiguration;
     Result producerResult = client.createProducer(topicName, producerConfiguration, producer);

2024-02-18 22:00:56.553 INFO  [0x16b7d3000] ExtensibleLoadManagerTest:138 | acked i:19
2024-02-18 22:00:56.553 INFO  [0x16b7d3000] ExtensibleLoadManagerTest:141 | consumer finished
2024-02-18 22:00:56.554 INFO  [0x1e3fea100] ClientImpl:666 | Closing Pulsar client with 1 producers and 1 consumers
2024-02-18 22:00:56.554 INFO  [0x1e3fea100] ProducerImpl:799 | [persistent://public/unload-test/topic-1708264824, cluster-a-1-0] Closing producer for topic persistent://public/unload-test/topic-1708264824
2024-02-18 22:00:56.554 INFO  [0x1e3fea100] ConsumerImpl:1267 | [persistent://public/unload-test/topic-1708264824, sub, 0] Closing consumer for topic persistent://public/unload-test/topic-1708264824
2024-02-18 22:00:56.561 INFO  [0x16b1cf000] ProducerImpl:763 | [persistent://public/unload-test/topic-1708264824, cluster-a-1-0] Closed producer 0
2024-02-18 22:00:56.561 INFO  [0x16b1cf000] ConsumerImpl:1251 | [persistent://public/unload-test/topic-1708264824, sub, 0] Closed consumer 0
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:1320 | [[::1]:53157 -> [::1]:6650] Connection disconnected (refCnt: 2)
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:1320 | [[::1]:53154 -> [::1]:6650] Connection disconnected (refCnt: 1)
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:1320 | [[::1]:53164 -> [::1]:6651] Connection disconnected (refCnt: 1)
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:1320 | [[::1]:53181 -> [::1]:6651] Connection disconnected (refCnt: 1)
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:1320 | [[::1]:53153 -> [::1]:6650] Connection disconnected (refCnt: 1)
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:1320 | [[::1]:53163 -> [::1]:6651] Connection disconnected (refCnt: 1)
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:275 | [[::1]:53157 -> [::1]:6650] Destroyed connection to pulsar://broker-1:6650-0
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:275 | [[::1]:53181 -> [::1]:6651] Destroyed connection to pulsar://green-broker-2:6650-0
2024-02-18 22:00:56.561 INFO  [0x16b143000] ClientConnection:275 | [[::1]:53164 -> [::1]:6651] Destroyed connection to pulsar://green-broker-1:6650-0
2024-02-18 22:00:56.562 INFO  [0x16b143000] ClientConnection:275 | [[::1]:53163 -> [::1]:6651] Destroyed connection to pulsar://localhost:6651-0
2024-02-18 22:00:56.562 INFO  [0x16b143000] ClientConnection:275 | [[::1]:53153 -> [::1]:6650] Destroyed connection to pulsar://localhost:6650-0
2024-02-18 22:00:56.562 INFO  [0x16b143000] ClientConnection:275 | [[::1]:53154 -> [::1]:6650] Destroyed connection to pulsar://broker-2:6650-0
./run-unit-tests.sh: line 40: 13856 Segmentation fault: 11  $CMAKE_BUILD_DIRECTORY/tests/ExtensibleLoadManagerTest

It appears to be something wrong with the thread safety.

[heesung-sn]

I changed the IO threads to 8 for ExtensibleLoadManagerTest and found segmentation fault when closing the client.

Thanks for sharing this. I tried to reproduce this issue, but I couldn't. Updated the test config instead.

[BewareMyPower]

Okay. I will debug it locally and see if it's a serious problem.

The segfault is not related to this PR