[fix][ws] Check the validity of config before start websocket service

[Shawyeok]

Motivation

Now if user start a websocket service without clusterName, service will be started as normal, but it'll get NPE in the after produce request.

The websocket service will log this line below:

2024-03-09T16:53:22,468 - WARN  - [pulsar-websocket-web-1-1:ProducerHandler@129] - \
  [[0:0:0:0:0:0:0:1]:49221] Failed in creating producer on topic persistent://public/non-exist/my-topic: java.lang.NullPointerException

The NPE stacktrace (which is missing in log)

org.apache.pulsar.broker.PulsarServerException: java.lang.NullPointerException
	at org.apache.pulsar.websocket.WebSocketService.retrieveClusterData(WebSocketService.java:261) ~[classes/:?]
	at org.apache.pulsar.websocket.WebSocketService.getPulsarClient(WebSocketService.java:185) ~[classes/:?]
	at org.apache.pulsar.websocket.ProducerHandler.(ProducerHandler.java:111) ~[classes/:?]
	at org.apache.pulsar.websocket.WebSocketProducerServlet.lambda$configure$0(WebSocketProducerServlet.java:43) ~[classes/:?]
	at org.eclipse.jetty.websocket.server.WebSocketServerFactory.acceptWebSocket(WebSocketServerFactory.java:275) ~[websocket-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.websocket.server.WebSocketServerFactory.acceptWebSocket(WebSocketServerFactory.java:260) ~[websocket-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.websocket.servlet.WebSocketServlet.service(WebSocketServlet.java:160) ~[websocket-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) ~[javax.servlet-api-3.1.0.jar:3.1.0]
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1656) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.servlets.QoSFilter.doFilter(QoSFilter.java:202) ~[jetty-servlets-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:552) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1440) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:505) ~[jetty-servlet-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1355) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:234) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.Server.handle(Server.java:516) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:487) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:732) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:479) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277) ~[jetty-server-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311) ~[jetty-io-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105) ~[jetty-io-9.4.54.v20240208.jar:9.4.54.v20240208]
	at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104) ~[jetty-io-9.4.54.v20240208.jar:9.4.54.v20240208]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.105.Final.jar:4.1.105.Final]
	at java.lang.Thread.run(Thread.java:833) ~[?:?]
Caused by: java.lang.NullPointerException
	at java.util.Objects.requireNonNull(Objects.java:208) ~[?:?]
	at com.google.common.base.Joiner.toString(Joiner.java:484) ~[guava-32.1.2-jre.jar:?]
	at com.google.common.base.Joiner.appendTo(Joiner.java:119) ~[guava-32.1.2-jre.jar:?]
	at com.google.common.base.Joiner.appendTo(Joiner.java:168) ~[guava-32.1.2-jre.jar:?]
	at com.google.common.base.Joiner.appendTo(Joiner.java:154) ~[guava-32.1.2-jre.jar:?]
	at com.google.common.base.Joiner.appendTo(Joiner.java:182) ~[guava-32.1.2-jre.jar:?]
	at org.apache.pulsar.broker.resources.BaseResources.joinPath(BaseResources.java:239) ~[classes/:?]
	at org.apache.pulsar.broker.resources.ClusterResources.getCluster(ClusterResources.java:67) ~[classes/:?]
	at org.apache.pulsar.websocket.WebSocketService.retrieveClusterData(WebSocketService.java:258) ~[classes/:?]
	... 38 more

Modifications

• Check the validity of websocket config before it start
• Log stacktrace if we get internal error in ProducerHandler

Verifying this change

• Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

Matching PR in forked repository

PR in forked repository: Shawyeok#12

[Shawyeok]

/pulsarbot rerun-failure-checks

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.64%. Comparing base (bbc6224) to head (828eb90).
Report is 48 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #22231      +/-   ##
============================================
+ Coverage     73.57%   73.64%   +0.07%     
+ Complexity    32624    32266     -358     
============================================
  Files          1877     1879       +2     
  Lines        139502   139801     +299     
  Branches      15299    15340      +41     
============================================
+ Hits         102638   102960     +322     
+ Misses        28908    28864      -44     
- Partials       7956     7977      +21     

Flag	Coverage Δ
inttests	26.59% <38.46%> (+2.01%)	⬆️
systests	24.30% <0.00%> (-0.02%)	⬇️
unittests	72.91% <61.53%> (+0.07%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...a/org/apache/pulsar/websocket/ProducerHandler.java	63.15% <100.00%> (+0.70%)	⬆️
...sar/websocket/service/WebSocketServiceStarter.java	76.00% <100.00%> (+1.53%)	⬆️

... and 75 files with indirect coverage changes