fix: Remove jolokia2 panic

plugins/inputs/jolokia2/common/gatherer.go

@@ -94,7 +94,13 @@ func (g *Gatherer) generatePoints(metric Metric, responses []ReadResponse) ([]po
 		}
 
 		pb := NewPointBuilder(metric, response.RequestAttributes, response.RequestPath)
-		for _, point := range pb.Build(metric.Mbean, response.Value) {
+		ps, err := pb.Build(metric.Mbean, response.Value)
+		if err != nil {
+			errors = append(errors, err)
+			continue
+		}
+
+		for _, point := range ps {
 			if response.RequestTarget != "" {
 				point.Tags["jolokia_agent_url"] = response.RequestTarget
 			}

plugins/inputs/jolokia2/common/point_builder.go

@@ -27,15 +27,15 @@ func NewPointBuilder(metric Metric, attributes []string, path string) *pointBuil
 }
 
 // Build generates a point for a given mbean name/pattern and value object.
-func (pb *pointBuilder) Build(mbean string, value interface{}) []point {
+func (pb *pointBuilder) Build(mbean string, value interface{}) ([]point, error) {
 	hasPattern := strings.Contains(mbean, "*")
-	if !hasPattern {
+	if !hasPattern || value == nil {
 		value = map[string]interface{}{mbean: value}
 	}
 
 	valueMap, ok := value.(map[string]interface{})
-	if !ok { // FIXME: log it and move on.
-		panic(fmt.Sprintf("There should be a map here for %s!\n", mbean))
+	if !ok {
+		return nil, fmt.Errorf("the response of %s's value should be a map", mbean)
 	}
 
 	points := make([]point, 0)
@@ -46,7 +46,7 @@ func (pb *pointBuilder) Build(mbean string, value interface{}) []point {
 		})
 	}
 
-	return compactPoints(points)
+	return compactPoints(points), nil
 }
 
 // extractTags generates the map of tags for a given mbean name/pattern.

stdout

@@ -0,0 +1,12 @@
+{"fields":{"CollectionUsage.committed":2321547264,"CollectionUsage.init":27262976,"CollectionUsage.max":-1,"CollectionUsage.used":0,"PeakUsage.committed":2480930816,"PeakUsage.init":27262976,"PeakUsage.max":-1,"PeakUsage.used":2361393152,"Usage.committed":2321547264,"Usage.init":27262976,"Usage.max":-1,"Usage.used":1138753536},"name":"java_memory_pool","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:8081/jolokia"},"timestamp":1656408750}
+{"fields":{"Uptime":450683712},"name":"jvm_runtime","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:8081/jolokia"},"timestamp":1656408750}
+{"fields":{"CollectionCount":164,"CollectionTime":2287},"name":"java_garbage_collector","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:8081/jolokia"},"timestamp":1656408750}
+{"fields":{"CollectionUsage.committed":15173353472,"CollectionUsage.init":15173353472,"CollectionUsage.max":15173353472,"CollectionUsage.used":145224304,"PeakUsage.committed":15173353472,"PeakUsage.init":15173353472,"PeakUsage.max":15173353472,"PeakUsage.used":2266522152,"Usage.committed":15173353472,"Usage.init":15173353472,"Usage.max":15173353472,"Usage.used":2266522152},"name":"java_memory_pool","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:7777/jolokia"},"timestamp":1656408750}
+{"fields":{"Uptime":709896},"name":"jvm_runtime","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:7777/jolokia"},"timestamp":1656408750}
+{"fields":{"CollectionCount":3,"CollectionTime":683},"name":"java_garbage_collector","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:7777/jolokia"},"timestamp":1656408750}
+{"fields":{"Uptime":450693641},"name":"jvm_runtime","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:8081/jolokia"},"timestamp":1656408760}
+{"fields":{"CollectionCount":0,"CollectionTime":0},"name":"java_garbage_collector","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:8081/jolokia"},"timestamp":1656408760}
+{"fields":{"CollectionUsage.committed":23068672,"CollectionUsage.init":0,"CollectionUsage.max":-1,"CollectionUsage.used":23068672,"PeakUsage.committed":4915200,"PeakUsage.init":2555904,"PeakUsage.max":8183808,"PeakUsage.used":4793344,"Usage.committed":4915200,"Usage.init":2555904,"Usage.max":8183808,"Usage.used":2489984},"name":"java_memory_pool","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:8081/jolokia"},"timestamp":1656408760}
+{"fields":{"Uptime":719737},"name":"jvm_runtime","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:7777/jolokia"},"timestamp":1656408760}
+{"fields":{"CollectionCount":3,"CollectionTime":683},"name":"java_garbage_collector","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:7777/jolokia"},"timestamp":1656408760}
+{"fields":{"CollectionUsage.committed":200605696,"CollectionUsage.init":200605696,"CollectionUsage.max":200605696,"CollectionUsage.used":87840720,"PeakUsage.committed":26935296,"PeakUsage.init":2555904,"PeakUsage.max":121737216,"PeakUsage.used":26904448,"Usage.committed":26935296,"Usage.init":2555904,"Usage.max":121737216,"Usage.used":26904448},"name":"java_memory_pool","tags":{"host":"shijinchendeMacBook-Pro.local","jolokia_agent_url":"http://100.100.61.230:7777/jolokia"},"timestamp":1656408760}