(solr) branch main updated: SOLR-17108: Prometheus Exporter: do not throw NullPointerException. (#2057)

[dsmiley]

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dsmiley pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/solr.git


The following commit(s) were added to refs/heads/main by this push:
     new afa6cfcdba1 SOLR-17108: Prometheus Exporter: do not throw 
NullPointerException. (#2057)
afa6cfcdba1 is described below

commit afa6cfcdba1ea55e82abea09f0bcd722e44689d6
Author: David Smiley <dsmi...@apache.org>
AuthorDate: Mon Jan 1 17:41:08 2024 -0500

    SOLR-17108: Prometheus Exporter: do not throw NullPointerException. (#2057)
    
    Prometheus Exporter: don't throw NPE; gracefully handle no metrics
---
 .../java/org/apache/solr/prometheus/scraper/SolrScraper.java   | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git 
a/solr/prometheus-exporter/src/java/org/apache/solr/prometheus/scraper/SolrScraper.java
 
b/solr/prometheus-exporter/src/java/org/apache/solr/prometheus/scraper/SolrScraper.java
index a65de0de431..273f6826176 100644
--- 
a/solr/prometheus-exporter/src/java/org/apache/solr/prometheus/scraper/SolrScraper.java
+++ 
b/solr/prometheus-exporter/src/java/org/apache/solr/prometheus/scraper/SolrScraper.java
@@ -133,17 +133,23 @@ public abstract class SolrScraper implements Closeable {
     QueryRequest queryRequest = new QueryRequest(query.getParameters());
     queryRequest.setPath(query.getPath());
 
-    NamedList<Object> queryResponse = null;
+    NamedList<Object> queryResponse;
     try {
-      if (!query.getCollection().isPresent() && !query.getCore().isPresent()) {
+      if (query.getCollection().isEmpty() && query.getCore().isEmpty()) {
         queryResponse = client.request(queryRequest);
       } else if (query.getCore().isPresent()) {
         queryResponse = client.request(queryRequest, query.getCore().get());
       } else if (query.getCollection().isPresent()) {
         queryResponse = client.request(queryRequest, 
query.getCollection().get());
+      } else {
+        throw new AssertionError("Invalid configuration");
+      }
+      if (queryResponse == null) { // ideally we'd make this impossible
+        throw new RuntimeException("no response from server");
       }
     } catch (SolrServerException | IOException e) {
       log.error("failed to request: {}", queryRequest.getPath(), e);
+      return samples;
     }
 
     JsonNode jsonNode = OBJECT_MAPPER.readTree((String) 
queryResponse.get("response"));