Add NPE check for PulsarService#getAdminClient (#9782)
### Motivation
If user set incorrect `brokerClientTlsEnabled` config, the `PulsarService#getAdminClient` would throw NPE and the error logs is not clear. For example, start a standalone pulsar with `brokerClientTlsEnabled=true`, some admin APIs that don't involve `PulsarService#getAdminClient` work well, however some admin APIs like `GET /admin/v2/non-persistent/:tenant/:namespace` will throw NPE with following logs:
```
org.apache.pulsar.broker.PulsarServerException: java.lang.NullPointerException
at org.apache.pulsar.broker.PulsarService.getAdminClient(PulsarService.java:1193)
at org.apache.pulsar.broker.admin.v2.NonPersistentTopics.getList(NonPersistentTopics.java:273)
```
After this PR, the logs became:
```
org.apache.pulsar.broker.PulsarServerException: java.lang.IllegalArgumentException: adminApiUrl is null, isBrokerClientTlsEnabled: true, webServiceAddressTls: null, webServiceAddress: http://localhost:8080
```
### Modifications
- Check if `adminApiUrl` is null in `PulsarService#getAdminClient` and give a human readable error message.
### Verifying this change
- [ ] Make sure that the change passes the CI checks.
This change is a trivial rework / code cleanup without any test coverage.
diff --git a/pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java b/pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java
index 25c497c..541d05e 100644
--- a/pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java
+++ b/pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java
@@ -1166,7 +1166,13 @@
if (this.adminClient == null) {
try {
ServiceConfiguration conf = this.getConfiguration();
- String adminApiUrl = conf.isBrokerClientTlsEnabled() ? webServiceAddressTls : webServiceAddress;
+ final String adminApiUrl = conf.isBrokerClientTlsEnabled() ? webServiceAddressTls : webServiceAddress;
+ if (adminApiUrl == null) {
+ throw new IllegalArgumentException("Web service address was not set properly "
+ + ", isBrokerClientTlsEnabled: " + conf.isBrokerClientTlsEnabled()
+ + ", webServiceAddressTls: " + webServiceAddressTls
+ + ", webServiceAddress: " + webServiceAddress);
+ }
PulsarAdminBuilder builder = PulsarAdmin.builder().serviceHttpUrl(adminApiUrl) //
.authentication(//
conf.getBrokerClientAuthenticationPlugin(), //
