Merge pull request #14 from Intellection/fix-index-out-of-range

Fix index out of range panic

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.7.1
+
+### Bug Fixes
+* Prevent index out of range panics when passenger processes are killed.
+
 ## 0.7.0
 
 * Change group to `nobody` instead of `nogroup`.

VERSION

@@ -1 +1 @@
-0.5.1
+0.7.1

passenger_exporter.go

@@ -276,7 +276,7 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 		ch <- prometheus.MustNewConstMetric(e.appProcsSpawning, prometheus.GaugeValue, parseFloat(sg.Group.ProcessesSpawning), sg.Name)
 
 		// Update process identifiers map.
-		processIdentifiers = updateProcesses(processIdentifiers, sg.Group.Processes)
+		processIdentifiers = updateProcesses(processIdentifiers, sg.Group.Processes, parseInt(info.MaxProcessCount))
 		for _, proc := range sg.Group.Processes {
 			if bucketID, ok := processIdentifiers[proc.PID]; ok {
 				ch <- prometheus.MustNewConstMetric(e.procMemory, prometheus.GaugeValue, parseFloat(proc.RealMemory), sg.Name, strconv.Itoa(bucketID))
@@ -345,6 +345,15 @@ func parseFloat(val string) float64 {
 	return v
 }
 
+func parseInt(val string) int {
+	v, err := strconv.Atoi(val)
+	if err != nil {
+		log.Errorf("failed to parse %s: %v", val, err)
+		v = 0
+	}
+	return v
+}
+
 // updateProcesses updates the global map from process id:exporter id. Process
 // TTLs cause new processes to be created on a user-defined cycle. When a new
 // process replaces an old process, the new process's statistics will be
@@ -356,10 +365,10 @@ func parseFloat(val string) float64 {
 // process/pid appears, it is mapped to either the first empty place
 // within the global map storing process identifiers, or mapped to
 // pid:id pair in the map.
-func updateProcesses(old map[string]int, processes []Process) map[string]int {
+func updateProcesses(old map[string]int, processes []Process, maxProcesses int) map[string]int {
 	var (
 		updated = make(map[string]int)
-		found   = make([]string, len(old))
+		found   = make([]string, maxProcesses)
 		missing []string
 	)
 

passenger_exporter_test.go

@@ -115,23 +115,26 @@ func TestStatusTimeout(t *testing.T) {
 }
 
 type updateProcessSpec struct {
-	name      string
-	input     map[string]int
-	processes []Process
-	output    map[string]int
+	name         string
+	input        map[string]int
+	processes    []Process
+	maxProcesses int
+	output       map[string]int
 }
 
 func newUpdateProcessSpec(
 	name string,
 	input map[string]int,
 	processes []Process,
+	maxProcesses int,
 ) updateProcessSpec {
 	s := updateProcessSpec{
-		name:      name,
-		input:     input,
-		processes: processes,
+		name:         name,
+		input:        input,
+		processes:    processes,
+		maxProcesses: maxProcesses,
 	}
-	s.output = updateProcesses(s.input, s.processes)
+	s.output = updateProcesses(s.input, s.processes, s.maxProcesses)
 	return s
 }
 
@@ -145,6 +148,7 @@ func TestUpdateProcessIdentifiers(t *testing.T) {
 				Process{PID: "cdf"},
 				Process{PID: "dfe"},
 			},
+			3,
 		),
 		newUpdateProcessSpec(
 			"1:1",
@@ -158,6 +162,7 @@ func TestUpdateProcessIdentifiers(t *testing.T) {
 				Process{PID: "cdf"},
 				Process{PID: "dfe"},
 			},
+			6,
 		),
 		newUpdateProcessSpec(
 			"increase processes",
@@ -174,6 +179,7 @@ func TestUpdateProcessIdentifiers(t *testing.T) {
 				Process{PID: "jkl"},
 				Process{PID: "lmn"},
 			},
+			9,
 		),
 		newUpdateProcessSpec(
 			"reduce processes",
@@ -190,6 +196,33 @@ func TestUpdateProcessIdentifiers(t *testing.T) {
 				Process{PID: "cdf"},
 				Process{PID: "dfe"},
 			},
+			6,
+		),
+		newUpdateProcessSpec(
+			"first process killed",
+			map[string]int{
+				"abc": 0,
+				"cdf": 1,
+				"dfe": 2,
+			},
+			[]Process{
+				Process{PID: "cdf"},
+				Process{PID: "dfe"},
+			},
+			3,
+		),
+		newUpdateProcessSpec(
+			"second process killed",
+			map[string]int{
+				"abc": 0,
+				"cdf": 1,
+				"dfe": 2,
+			},
+			[]Process{
+				Process{PID: "abc"},
+				Process{PID: "dfe"},
+			},
+			3,
 		),
 	} {
 		if len(spec.output) != len(spec.processes) {
@@ -202,7 +235,7 @@ func TestUpdateProcessIdentifiers(t *testing.T) {
 			}
 		}
 
-		newOutput := updateProcesses(spec.output, spec.processes)
+		newOutput := updateProcesses(spec.output, spec.processes, spec.maxProcesses)
 		if !reflect.DeepEqual(newOutput, spec.output) {
 			t.Fatalf("case %s: updateProcesses is not idempotent", spec.name)
 		}
@@ -224,6 +257,7 @@ func TestInsertingNewProcesses(t *testing.T) {
 			Process{PID: "newPID"},
 			Process{PID: "newPID2"},
 		},
+		6,
 	)
 
 	if len(spec.output) != len(spec.processes) {