feat: enhance stdin check and add tests parsing error

Signed-off-by: François Gouteroux <francois.gouteroux@gmail.com>

cmd/promtool/main.go

@@ -185,7 +185,7 @@ func main() {
 	pushMetricsCmd.Arg("remote-write-url", "Prometheus remote write url to push metrics.").Required().URLVar(&remoteWriteURL)
 	metricFiles := pushMetricsCmd.Arg(
 		"metric-files",
-		"The metric files to push, default is read from standard input (STDIN).",
+		"The metric files to push, default is read from standard input.",
 	).ExistingFiles()
 	pushMetricsLabels := pushMetricsCmd.Flag("label", "Label to attach to metrics. Can be specified multiple times.").Default("job=promtool").StringMap()
 	pushMetricsTimeout := pushMetricsCmd.Flag("timeout", "The time to wait for pushing metrics.").Default("30s").Duration()

cmd/promtool/metrics.go

@@ -33,8 +33,6 @@ import (
 
 // Push metrics to a prometheus remote write (for testing purpose only).
 func PushMetrics(url *url.URL, roundTripper http.RoundTripper, headers map[string]string, timeout time.Duration, labels map[string]string, files ...string) int {
-	failed := false
-
 	addressURL, err := url.Parse(url.String())
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
@@ -63,63 +61,37 @@ func PushMetrics(url *url.URL, roundTripper http.RoundTripper, headers map[strin
 		headers:      headers,
 	}
 
-	// add empty string to avoid matching filename
+	var data []byte
+	var failed bool
+
 	if len(files) == 0 {
-		files = append(files, "")
+		data, err = io.ReadAll(os.Stdin)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "  FAILED:", err)
+			return failureExitCode
+		}
+		fmt.Printf("Parsing standard input\n")
+		if parseAndPushMetrics(client, data, labels) {
+			fmt.Printf("  SUCCESS: metrics pushed to remote write.\n")
+			return successExitCode
+		}
+		return failureExitCode
 	}
 
 	for _, file := range files {
-		var data []byte
-		var err error
-
-		// if file is an empty string it is a stdin
-		if file == "" {
-			data, err = io.ReadAll(os.Stdin)
-			if err != nil {
-				fmt.Fprintln(os.Stderr, "  FAILED:", err)
-				failed = true
-				break
-			}
-
-			fmt.Printf("Parsing input from stdin\n")
-		} else {
-			data, err = os.ReadFile(file)
-			if err != nil {
-				fmt.Fprintln(os.Stderr, "  FAILED:", err)
-				failed = true
-				continue
-			}
-
-			fmt.Printf("Parsing input from metric file %s\n", file)
-		}
-		metricsData, err := fmtutil.ParseMetricsTextAndFormat(bytes.NewReader(data), labels)
+		data, err = os.ReadFile(file)
 		if err != nil {
 			fmt.Fprintln(os.Stderr, "  FAILED:", err)
 			failed = true
 			continue
 		}
 
-		raw, err := metricsData.Marshal()
-		if err != nil {
-			fmt.Fprintln(os.Stderr, "  FAILED:", err)
-			failed = true
+		fmt.Printf("Parsing metrics file %s\n", file)
+		if parseAndPushMetrics(client, data, labels) {
+			fmt.Printf("  SUCCESS: metrics file %s pushed to remote write.\n", file)
 			continue
 		}
-
-		// Encode the request body into snappy encoding.
-		compressed := snappy.Encode(nil, raw)
-		err = client.Store(context.Background(), compressed)
-		if err != nil {
-			fmt.Fprintln(os.Stderr, "  FAILED:", err)
-			failed = true
-			continue
-		}
-
-		if file == "" {
-			fmt.Printf("  SUCCESS: metric pushed to remote write.\n")
-		} else {
-			fmt.Printf("  SUCCESS: metric file %s pushed to remote write.\n", file)
-		}
+		failed = true
 	}
 
 	if failed {
@@ -129,6 +101,30 @@ func PushMetrics(url *url.URL, roundTripper http.RoundTripper, headers map[strin
 	return successExitCode
 }
 
+func parseAndPushMetrics(client *remote.Client, data []byte, labels map[string]string) bool {
+	metricsData, err := fmtutil.ParseMetricsTextAndFormat(bytes.NewReader(data), labels)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "  FAILED:", err)
+		return false
+	}
+
+	raw, err := metricsData.Marshal()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "  FAILED:", err)
+		return false
+	}
+
+	// Encode the request body into snappy encoding.
+	compressed := snappy.Encode(nil, raw)
+	err = client.Store(context.Background(), compressed)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "  FAILED:", err)
+		return false
+	}
+
+	return true
+}
+
 type setHeadersTransport struct {
 	http.RoundTripper
 	headers map[string]string

docs/command-line/promtool.md

@@ -410,7 +410,7 @@ Push metrics to a prometheus remote write (for testing purpose only).
 | Argument | Description | Required |
 | --- | --- | --- |
 | remote-write-url | Prometheus remote write url to push metrics. | Yes |
-| metric-files | The metric files to push, default is read from standard input (STDIN). |  |
+| metric-files | The metric files to push, default is read from standard input. |  |
 
 
 

util/fmtutil/format_test.go

@@ -173,7 +173,7 @@ var writeRequestFixture = &prompb.WriteRequest{
 	},
 }
 
-func TestParseMetricsTextAndFormat(t *testing.T) {
+func TestParseAndPushMetricsTextAndFormat(t *testing.T) {
 	input := bytes.NewReader([]byte(`
 	# HELP http_request_duration_seconds A histogram of the request duration.
 	# TYPE http_request_duration_seconds histogram
@@ -206,3 +206,28 @@ func TestParseMetricsTextAndFormat(t *testing.T) {
 
 	require.Equal(t, writeRequestFixture, expected)
 }
+
+func TestParseMetricsTextAndFormatErrorParsingFloatValue(t *testing.T) {
+	input := bytes.NewReader([]byte(`
+	# HELP http_requests_total The total number of HTTP requests.
+	# TYPE http_requests_total counter
+	http_requests_total{method="post",code="200"} 1027Error 1395066363000
+	http_requests_total{method="post",code="400"}    3 1395066363000
+	`))
+	labels := map[string]string{"job": "promtool"}
+
+	_, err := ParseMetricsTextAndFormat(input, labels)
+	require.Equal(t, err.Error(), "text format parsing error in line 4: expected float as value, got \"1027Error\"")
+}
+
+func TestParseMetricsTextAndFormatErrorParsingMetricType(t *testing.T) {
+	input := bytes.NewReader([]byte(`
+	# HELP node_info node info summary.
+	# TYPE node_info info
+	node_info{test="summary"} 1 1395066363000
+	`))
+	labels := map[string]string{"job": "promtool"}
+
+	_, err := ParseMetricsTextAndFormat(input, labels)
+	require.Equal(t, err.Error(), "text format parsing error in line 3: unknown metric type \"info\"")
+}