Upgrade prometheus/common to v0.67.5 and use NewTextParser

In v0.67.5 the zero-value TextParser panics because the ValidationScheme
enum was reordered: UnsetValidation=0 (new), LegacyValidation=1,
UTF8Validation=2. The TextParser.scheme field defaults to zero which now
maps to UnsetValidation and panics in IsValidMetricName.

Use expfmt.NewTextParser(model.LegacyValidation) to explicitly initialize
the parser with the correct validation scheme. Add comprehensive test
coverage for all prometheus metric types (counter, gauge, histogram,
summary), multiple metric families, malformed input, empty output, NaN
handling, and special character labels.

Signed-off-by: Sarvodaya Kumar <sarvodaya.kumar.ctr@sumologic.com>

Author: sarvodaya-kumar-26

agent/check_handler_internal_test.go

@@ -606,6 +606,49 @@ func TestExtractMetricsPanicRecovery(t *testing.T) {
 	})
 }
 
+func TestExtractMetricsPrometheus(t *testing.T) {
+	event := &corev2.Event{
+		Check: &corev2.Check{
+			ObjectMeta: corev2.ObjectMeta{
+				Name:      "disk-usage",
+				Namespace: "default",
+			},
+			Output:             "# HELP node_filesystem_avail_bytes Filesystem space available.\n# TYPE node_filesystem_avail_bytes gauge\nnode_filesystem_avail_bytes{device=\"/dev/sda1\",mountpoint=\"/\"} 5.3687091e+10\n",
+			OutputMetricFormat: corev2.PrometheusOutputMetricFormat,
+		},
+	}
+
+	metrics := extractMetrics(event)
+	require.NotNil(t, metrics)
+	assert.Equal(t, 1, len(metrics))
+	assert.Equal(t, "node_filesystem_avail_bytes", metrics[0].Name)
+	assert.Equal(t, 5.3687091e+10, metrics[0].Value)
+}
+
+func TestExtractMetricsPrometheusMultiFamily(t *testing.T) {
+	event := &corev2.Event{
+		Check: &corev2.Check{
+			ObjectMeta: corev2.ObjectMeta{
+				Name:      "node-metrics",
+				Namespace: "default",
+			},
+			Output: "# HELP node_cpu_seconds_total Seconds the CPUs spent in each mode.\n# TYPE node_cpu_seconds_total counter\nnode_cpu_seconds_total{cpu=\"0\",mode=\"idle\"} 123456.78\nnode_cpu_seconds_total{cpu=\"0\",mode=\"system\"} 4567.89\n# HELP node_load1 1m load average.\n# TYPE node_load1 gauge\nnode_load1 2.34\n",
+			OutputMetricFormat: corev2.PrometheusOutputMetricFormat,
+		},
+	}
+
+	metrics := extractMetrics(event)
+	require.NotNil(t, metrics)
+	assert.Equal(t, 3, len(metrics))
+
+	nameSet := make(map[string]bool)
+	for _, m := range metrics {
+		nameSet[m.Name] = true
+	}
+	assert.True(t, nameSet["node_cpu_seconds_total"])
+	assert.True(t, nameSet["node_load1"])
+}
+
 func TestFailOnAssetCheckWithDisabledAssets(t *testing.T) {
 	config, cleanup := FixtureConfig()
 	defer cleanup()

agent/transformers/prometheus.go

@@ -65,7 +65,7 @@ func ParseProm(event *types.Event) PromList {
 	}
 
 	t := strings.NewReader(event.Check.Output)
-	var parser expfmt.TextParser
+	parser := expfmt.NewTextParser(model.LegacyValidation)
 	metricFamilies, err := parser.TextToMetricFamilies(t)
 
 	if err != nil {

agent/transformers/prometheus_test.go

@@ -228,6 +228,178 @@ func TestParsePromValidationScheme(t *testing.T) {
 	})
 }
 
+func TestParsePromCounter(t *testing.T) {
+	assert := assert.New(t)
+
+	event := types.FixtureEvent("test", "test")
+	event.Check.Output = "# HELP http_requests_total The total number of HTTP requests.\n# TYPE http_requests_total counter\nhttp_requests_total{method=\"post\",code=\"200\"} 1027\nhttp_requests_total{method=\"post\",code=\"400\"} 3\n"
+
+	prom := ParseProm(event)
+	assert.NotEmpty(prom)
+	points := prom.Transform()
+	assert.Equal(2, len(points))
+	assert.Equal("http_requests_total", points[0].Name)
+	assert.Equal("http_requests_total", points[1].Name)
+}
+
+func TestParsePromGauge(t *testing.T) {
+	assert := assert.New(t)
+
+	event := types.FixtureEvent("test", "test")
+	event.Check.Output = "# HELP node_memory_MemAvailable_bytes Memory information field MemAvailable_bytes.\n# TYPE node_memory_MemAvailable_bytes gauge\nnode_memory_MemAvailable_bytes 5.361664e+09\n"
+
+	prom := ParseProm(event)
+	assert.NotEmpty(prom)
+	points := prom.Transform()
+	assert.Equal(1, len(points))
+	assert.Equal("node_memory_MemAvailable_bytes", points[0].Name)
+	assert.Equal(5.361664e+09, points[0].Value)
+}
+
+func TestParsePromHistogram(t *testing.T) {
+	assert := assert.New(t)
+
+	event := types.FixtureEvent("test", "test")
+	event.Check.Output = "# HELP http_request_duration_seconds A histogram of the request duration.\n# TYPE http_request_duration_seconds histogram\nhttp_request_duration_seconds_bucket{le=\"0.05\"} 24054\nhttp_request_duration_seconds_bucket{le=\"0.1\"} 33444\nhttp_request_duration_seconds_bucket{le=\"0.2\"} 100392\nhttp_request_duration_seconds_bucket{le=\"+Inf\"} 144320\nhttp_request_duration_seconds_sum 53423\nhttp_request_duration_seconds_count 144320\n"
+
+	prom := ParseProm(event)
+	assert.NotEmpty(prom)
+	points := prom.Transform()
+	assert.True(len(points) >= 6)
+
+	nameSet := make(map[string]bool)
+	for _, p := range points {
+		nameSet[p.Name] = true
+	}
+	assert.True(nameSet["http_request_duration_seconds_bucket"])
+	assert.True(nameSet["http_request_duration_seconds_sum"])
+	assert.True(nameSet["http_request_duration_seconds_count"])
+}
+
+func TestParsePromSummary(t *testing.T) {
+	assert := assert.New(t)
+
+	event := types.FixtureEvent("test", "test")
+	event.Check.Output = "# HELP go_gc_duration_seconds A summary of pause duration of garbage collection cycles.\n# TYPE go_gc_duration_seconds summary\ngo_gc_duration_seconds{quantile=\"0\"} 3.3722e-05\ngo_gc_duration_seconds{quantile=\"0.25\"} 5.0129e-05\ngo_gc_duration_seconds{quantile=\"0.5\"} 0.000126547\ngo_gc_duration_seconds{quantile=\"1\"} 0.009688629\ngo_gc_duration_seconds_sum 17.391350544\ngo_gc_duration_seconds_count 12345\n"
+
+	prom := ParseProm(event)
+	assert.NotEmpty(prom)
+	points := prom.Transform()
+	assert.True(len(points) >= 6)
+
+	nameSet := make(map[string]bool)
+	for _, p := range points {
+		nameSet[p.Name] = true
+	}
+	assert.True(nameSet["go_gc_duration_seconds"])
+	assert.True(nameSet["go_gc_duration_seconds_sum"])
+	assert.True(nameSet["go_gc_duration_seconds_count"])
+}
+
+func TestParsePromMultipleMetricFamilies(t *testing.T) {
+	assert := assert.New(t)
+
+	event := types.FixtureEvent("test", "test")
+	event.Check.Output = "# HELP node_filesystem_avail_bytes Filesystem space available.\n# TYPE node_filesystem_avail_bytes gauge\nnode_filesystem_avail_bytes{device=\"/dev/sda1\",mountpoint=\"/\"} 5.3687091e+10\n# HELP node_filesystem_size_bytes Filesystem size in bytes.\n# TYPE node_filesystem_size_bytes gauge\nnode_filesystem_size_bytes{device=\"/dev/sda1\",mountpoint=\"/\"} 1.03079215104e+11\n# HELP node_cpu_seconds_total Seconds the CPUs spent in each mode.\n# TYPE node_cpu_seconds_total counter\nnode_cpu_seconds_total{cpu=\"0\",mode=\"idle\"} 123456.78\nnode_cpu_seconds_total{cpu=\"0\",mode=\"system\"} 4567.89\n"
+
+	prom := ParseProm(event)
+	assert.NotEmpty(prom)
+	points := prom.Transform()
+	assert.Equal(4, len(points))
+
+	nameSet := make(map[string]bool)
+	for _, p := range points {
+		nameSet[p.Name] = true
+	}
+	assert.True(nameSet["node_filesystem_avail_bytes"])
+	assert.True(nameSet["node_filesystem_size_bytes"])
+	assert.True(nameSet["node_cpu_seconds_total"])
+}
+
+func TestParsePromMalformedInput(t *testing.T) {
+	assert := assert.New(t)
+
+	testCases := []struct {
+		name   string
+		output string
+	}{
+		{"completely invalid", "this is not prometheus text at all"},
+		{"partial metric line", "http_requests_total{method=\"get\"}\n"},
+		{"missing value", "# TYPE foo counter\nfoo\n"},
+		{"truncated output", "# HELP foo A help message.\n# TYPE foo counter\n"},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			event := types.FixtureEvent("test", "test")
+			event.Check.Output = tc.output
+
+			assert.NotPanics(func() {
+				_ = ParseProm(event)
+			})
+		})
+	}
+}
+
+func TestParsePromEmptyOutput(t *testing.T) {
+	assert := assert.New(t)
+
+	event := types.FixtureEvent("test", "test")
+	event.Check.Output = ""
+
+	prom := ParseProm(event)
+	assert.Empty(prom)
+	points := prom.Transform()
+	assert.Nil(points)
+}
+
+func TestParsePromNaN(t *testing.T) {
+	assert := assert.New(t)
+
+	nanList := PromList{
+		&model.Sample{
+			Metric: model.Metric{
+				model.MetricNameLabel: "stale_metric",
+			},
+			Value:     model.SampleValue(math.NaN()),
+			Timestamp: model.TimeFromUnix(time.Now().Unix()),
+		},
+		&model.Sample{
+			Metric: model.Metric{
+				model.MetricNameLabel: "valid_metric",
+			},
+			Value:     42.0,
+			Timestamp: model.TimeFromUnix(time.Now().Unix()),
+		},
+	}
+
+	points := nanList.Transform()
+	assert.Equal(1, len(points))
+	assert.Equal("valid_metric", points[0].Name)
+	assert.Equal(42.0, points[0].Value)
+}
+
+func TestParsePromSpecialCharLabels(t *testing.T) {
+	assert := assert.New(t)
+
+	event := types.FixtureEvent("test", "test")
+	event.Check.Output = "# TYPE http_requests_total counter\nhttp_requests_total{method=\"GET\",path=\"/api/v1/users\",status_code=\"200\"} 1500\n"
+
+	prom := ParseProm(event)
+	assert.NotEmpty(prom)
+	points := prom.Transform()
+	assert.Equal(1, len(points))
+	assert.Equal("http_requests_total", points[0].Name)
+
+	tagMap := make(map[string]string)
+	for _, tag := range points[0].Tags {
+		tagMap[tag.Name] = tag.Value
+	}
+	assert.Equal("GET", tagMap["method"])
+	assert.Equal("/api/v1/users", tagMap["path"])
+	assert.Equal("200", tagMap["status_code"])
+}
+
 func TestTransformProm(t *testing.T) {
 	assert := assert.New(t)
 	ts := time.Now().Unix()

go.mod

@@ -51,8 +51,8 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0
 	github.com/olekukonko/tablewriter v0.0.5
 	github.com/prometheus/client_golang v1.20.5
-	github.com/prometheus/client_model v0.6.1
-	github.com/prometheus/common v0.62.0
+	github.com/prometheus/client_model v0.6.2
+	github.com/prometheus/common v0.67.5
 	github.com/robertkrimen/otto v0.2.1
 	github.com/robfig/cron/v3 v3.0.1
 	github.com/sensu/lasr v1.2.1
@@ -117,7 +117,7 @@ require (
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-ole/go-ole v1.2.6 // indirect
 	github.com/go-viper/mapstructure/v2 v2.5.0 // indirect
-	github.com/golang-jwt/jwt/v5 v5.2.2 // indirect
+	github.com/golang-jwt/jwt/v5 v5.3.0 // indirect
 	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/grpc-ecosystem/go-grpc-middleware/providers/prometheus v1.0.1 // indirect
 	github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.1.0 // indirect

go.sum

@@ -1514,8 +1514,8 @@ github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69
 github.com/golang-jwt/jwt/v4 v4.4.3/go.mod h1:m21LjoU+eqJr34lmDMbreY2eSTRJ1cv77w39/MY0Ch0=
 github.com/golang-jwt/jwt/v4 v4.5.2 h1:YtQM7lnr8iZ+j5q71MGKkNw9Mn7AjHM68uc9g5fXeUI=
 github.com/golang-jwt/jwt/v4 v4.5.2/go.mod h1:m21LjoU+eqJr34lmDMbreY2eSTRJ1cv77w39/MY0Ch0=
-github.com/golang-jwt/jwt/v5 v5.2.2 h1:Rl4B7itRWVtYIHFrSNd7vhTiz9UpLdi6gZhZ3wEeDy8=
-github.com/golang-jwt/jwt/v5 v5.2.2/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
+github.com/golang-jwt/jwt/v5 v5.3.0 h1:pv4AsKCKKZuqlgs5sUmn4x8UlGa0kEVt/puTpKx9vvo=
+github.com/golang-jwt/jwt/v5 v5.3.0/go.mod h1:fxCRLWMO43lRc8nhHWY6LGqRcf+1gQWArsqaEUEa5bE=
 github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/glog v1.0.0/go.mod h1:EWib/APOK0SL3dFbYqvxE3UYd8E6s1ouQ7iEp/0LWV4=
@@ -1806,10 +1806,11 @@ github.com/prometheus/client_model v0.3.0/go.mod h1:LDGWKZIo7rky3hgvBe+caln+Dr3d
 github.com/prometheus/client_model v0.4.0/go.mod h1:oMQmHW1/JoDwqLtg57MGgP/Fb1CJEYF2imWWhWtMkYU=
 github.com/prometheus/client_model v0.5.0/go.mod h1:dTiFglRmd66nLR9Pv9f0mZi7B7fk5Pm3gvsjB5tr+kI=
 github.com/prometheus/client_model v0.6.0/go.mod h1:NTQHnmxFpouOD0DpvP4XujX3CdOAGQPoaGhyTchlyt8=
-github.com/prometheus/client_model v0.6.1 h1:ZKSh/rekM+n3CeS952MLRAdFwIKqeY8b62p8ais2e9E=
 github.com/prometheus/client_model v0.6.1/go.mod h1:OrxVMOVHjw3lKMa8+x6HeMGkHMQyHDk9E3jmP2AmGiY=
-github.com/prometheus/common v0.62.0 h1:xasJaQlnWAeyHdUBeGjXmutelfJHWMRr+Fg4QszZ2Io=
-github.com/prometheus/common v0.62.0/go.mod h1:vyBcEuLSvWos9B1+CyL7JZ2up+uFzXhkqml0W5zIY1I=
+github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
+github.com/prometheus/client_model v0.6.2/go.mod h1:y3m2F6Gdpfy6Ut/GBsUqTWZqCUvMVzSfMLjcu6wAwpE=
+github.com/prometheus/common v0.67.5 h1:pIgK94WWlQt1WLwAC5j2ynLaBRDiinoAb86HZHTUGI4=
+github.com/prometheus/common v0.67.5/go.mod h1:SjE/0MzDEEAyrdr5Gqc6G+sXI67maCxzaT3A2+HqjUw=
 github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
 github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
 github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=