Malformed URL issue while deploying Samza on a pure IPv6 VM

[Vishal Ranjan]

In our product we are expanding our support for IPv6 environment. 
We earlier tested deploying Samza in a dual stack environment, and it worked 
fine.
Recently we got our hands on a pure IPv6 lab, and while testing we came across 
an issue when starting Samza.

Looking at the stack trace it seems like the url is not formed correctly for 
IPv6 deployment. The IPv6 address should have been decorated inside '[ ]’, but 
that isn’t the case.
Here is the stack trace. The ip of the VM where Samza is deployed is 
'fc00:192:168:22::14’.

2021-08-26T07:28:52.232Z INFO jetty.server.AbstractConnector main doStart:331 
Started ServerConnector@6c1cfa53{HTTP/1.1, (http/1.1)}{0.0.0.0:44843}
2021-08-26T07:28:52.232Z INFO jetty.server.Server main doStart:415 Started 
@5524ms
2021-08-26T07:28:52.235Z ERROR samza.clustermanager.ClusterBasedJobCoordinator 
main run:314 Exception thrown in the JobCoordinator loop
java.net.MalformedURLException: Error at index 3 in: "192:168:22:0:0:0:14:44843"
        at java.base/java.net.URL.<init>(URL.java:679)
        at java.base/java.net.URL.<init>(URL.java:541)
        at java.base/java.net.URL.<init>(URL.java:488)
        at 
org.apache.samza.coordinator.server.HttpServer.getUrl(HttpServer.scala:134)
        at 
org.apache.samza.coordinator.server.HttpServer.$anonfun$start$4(HttpServer.scala:113)
        at org.apache.samza.util.Logging.info(Logging.scala:63)
        at org.apache.samza.util.Logging.info$(Logging.scala:61)
        at 
org.apache.samza.coordinator.server.HttpServer.info(HttpServer.scala:39)
        at 
org.apache.samza.coordinator.server.HttpServer.start(HttpServer.scala:113)
        at 
org.apache.samza.job.yarn.SamzaYarnAppMasterService.onInit(SamzaYarnAppMasterService.scala:53)
        at 
org.apache.samza.job.yarn.YarnClusterResourceManager.start(YarnClusterResourceManager.java:212)
        at 
org.apache.samza.clustermanager.ContainerProcessManager.start(ContainerProcessManager.java:230)
        at 
org.apache.samza.clustermanager.ClusterBasedJobCoordinator.run(ClusterBasedJobCoordinator.java:289)
        at 
org.apache.samza.clustermanager.ClusterBasedJobCoordinator.runClusterBasedJobCoordinator(ClusterBasedJobCoordinator.java:547)
        at 
org.apache.samza.clustermanager.ClusterBasedJobCoordinator.main(ClusterBasedJobCoordinator.java:473)
Caused by: java.lang.NumberFormatException: Error at index 3 in: 
"192:168:22:0:0:0:14:44843"
        at 
java.base/java.lang.NumberFormatException.forCharSequence(NumberFormatException.java:81)
        at java.base/java.lang.Integer.parseInt(Integer.java:735)
        at 
java.base/java.net.URLStreamHandler.parseURL(URLStreamHandler.java:223)

This is the problematic line of code: 
~l/.m2/repository/org/apache/samza/samza-core_2.12/1.5.1-arkin-jdk11/samza-core_2.12-1.5.1-arkin-jdk11-sources.jar!/org/apache/samza/coordinator/server/HttpServer.scala:134
 new URL("http://"; + Util.getLocalHost.getHostName + ":" + runningPort + 
rootPath)


While we are planning to add a patch (proper decoration based on IP type) to 
fix this, we are not certain if there will be any further issue with IPv6. 
We searched over internet but couldn’t find whether Samza supports IPv6 or not. 
We need to know if there will be any further issues or not.

We are at a crucial stage of release cycle, and having a proper estimate will 
help us plan better. Any help on this matter is highly appreciated.

Thanks,
Vishal