[improve] Prometheus streaming parsing optimization enhancements (#3761)

Signed-off-by: Duansg <siguoduan@gmail.com> Co-authored-by: Sherlock Yin <sherlock.yin1994@gmail.com> Co-authored-by: Calvin <zhengqiwei@apache.org> Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Co-authored-by: Tom <tomsun28@outlook.com>
2026-09-17 09:40:58 +00:00 · 2025-09-21 23:34:06 +08:00
parent b93613c25e
commit c5f0389138
3 changed files with 579 additions and 19 deletions
@@ -627,13 +627,15 @@ public class HttpCollectImpl extends AbstractCollect {
    }

    private void parseResponseByPrometheusExporter(InputStream content, List<String> aliasFields, CollectRep.MetricsData.Builder builder) throws IOException {
-        Map<String, MetricFamily> metricFamilyMap = OnlineParser.parseMetrics(content);
+        String metrics = builder.getMetrics();
+        Map<String, MetricFamily> metricFamilyMap = OnlineParser.parseMetrics(content, metrics);
        if (metricFamilyMap == null || metricFamilyMap.isEmpty()) {
            return;
        }
-        String metrics = builder.getMetrics();
-        if (metricFamilyMap.containsKey(metrics)) {
        MetricFamily metricFamily = metricFamilyMap.get(metrics);
+        if (null == metricFamily || CollectionUtils.isEmpty(metricFamily.getMetricList())) {
+            return;
+        }
        for (MetricFamily.Metric metric : metricFamily.getMetricList()) {
            Map<String, String> labelMap = metric.getLabels()
                    .stream()
@@ -652,7 +654,7 @@ public class HttpCollectImpl extends AbstractCollect {
            builder.addValueRow(valueRowBuilder.build());
        }
    }
-    }
+

    private void parseResponseByDefault(String resp, List<String> aliasFields, HttpProtocol http,
                                        CollectRep.MetricsData.Builder builder, Long responseTime) {
@@ -81,6 +81,114 @@ public class OnlineParser {
        return metricFamilyMap;
    }

+    /**
+     * Parses Prometheus metrics from the given {@link InputStream}, but only for the specified metric name.
+     * <p>
+     * This method differs from {@link #parseMetrics(InputStream)} in that it filters and parses only the metric
+     * with the given name, rather than parsing all available metrics from the input stream.
+     *
+     * @param inputStream the input stream containing Prometheus metrics data
+     * @param metric the name of the metric to filter and parse (case-insensitive)
+     * @return a map of metric family names to {@link MetricFamily} objects, or {@code null} if parsing fails
+     * @throws IOException if an I/O error occurs while reading from the input stream
+     */
+    public static Map<String, MetricFamily> parseMetrics(InputStream inputStream, String metric) throws IOException {
+        Map<String, MetricFamily> metricFamilyMap = new ConcurrentHashMap<>(10);
+        try {
+            int i = getChar(inputStream);
+            while (i != -1) {
+                if (i == '#' || i == '\n') {
+                    skipToLineEnd(inputStream).maybeEol().maybeEof().noElse();
+                } else {
+                    StringBuilder stringBuilder = new StringBuilder();
+                    stringBuilder.append((char) i);
+
+                    // parse the metricName to filter.
+                    int next = parseMetricName(inputStream, stringBuilder).maybeSpace().maybeLeftBracket().noElse();
+                    String metricName = stringBuilder.toString();
+                    stringBuilder.delete(0, stringBuilder.length());
+
+                    // step2: Determine whether this metric should be parsed.
+                    if (metric.equals(metricName)) {
+                        parseMetricFromName(inputStream, stringBuilder, metricFamilyMap, metricName, next);
+                    } else {
+                        skipToLineEnd(inputStream).maybeEol().maybeEof().noElse();
+                    }
+                }
+                i = getChar(inputStream);
+                // To address the `\n\r` scenario, it is necessary to skip
+                if (i == '\r') {
+                    i = getChar(inputStream);
+                }
+            }
+        } catch (FormatException e) {
+            log.error("prometheus parser failed because of wrong input format. {}", e.getMessage());
+            return null;
+        }
+        return metricFamilyMap;
+    }
+
+    /**
+     * Start parsing the complete metric from the already parsed metric name.
+     *
+     * @param inputStream      the input stream containing the metric data
+     * @param stringBuilder    the StringBuilder used for parsing and temporary storage
+     * @param metricFamilyMap  the map to store parsed MetricFamily objects, keyed by metric name
+     * @param metricName       the name of the metric to parse
+     * @param next             the next character to process from the input stream
+     * @return a CharChecker containing the next character after parsing the metric
+     * @throws IOException     if an I/O error occurs while reading the input stream
+     * @throws FormatException if the input format is invalid
+     */
+    private static CharChecker parseMetricFromName(InputStream inputStream, StringBuilder stringBuilder,
+                                                   Map<String, MetricFamily> metricFamilyMap,
+                                                   String metricName, int next) throws IOException, FormatException {
+        MetricFamily metricFamily;
+        MetricFamily.Metric metric = new MetricFamily.Metric();
+
+        if (!metricFamilyMap.containsKey(metricName)) {
+            metricFamily = new MetricFamily();
+            metricFamily.setMetricList(new ArrayList<>());
+            metricFamily.setName(metricName);
+            metricFamilyMap.put(metricName, metricFamily);
+        } else {
+            metricFamily = metricFamilyMap.get(metricName);
+        }
+        int i = next;
+        if (i == ' ') {
+            i = skipSpaces(inputStream).getInt();
+        }
+
+        List<MetricFamily.Label> labelList = new LinkedList<>();
+        metric.setLabels(labelList);
+        if (i == '{') {
+            parseLabels(inputStream, stringBuilder, labelList);
+            i = skipSpaces(inputStream).getInt();
+        }
+
+        stringBuilder.delete(0, stringBuilder.length());
+        stringBuilder.append((char) i);
+        i = parseOneDouble(inputStream, stringBuilder).maybeSpace().maybeEol().maybeEof().noElse();
+        metric.setValue(toDouble(stringBuilder.toString()));
+        if (i == '\n' || i == -1) {
+            metricFamily.getMetricList().add(metric);
+            return new CharChecker(i);
+        }
+
+        i = skipSpaces(inputStream).getInt();
+        stringBuilder.delete(0, stringBuilder.length());
+        stringBuilder.append((char) i);
+        i = skipOneLong(inputStream).maybeSpace().maybeEol().maybeEof().noElse();
+        if (i == '\n' || i == -1) {
+            metricFamily.getMetricList().add(metric);
+            return new CharChecker(i);
+        }
+        i = skipSpaces(inputStream).maybeEol().maybeEof().noElse();
+
+        metricFamily.getMetricList().add(metric);
+        return new CharChecker(i);
+    }
+
    private static class FormatException extends Exception {

        public FormatException() {
@@ -0,0 +1,450 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hertzbeat.collector.collect.prometheus.parser;
+
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+/**
+ * Parse a Single metric in prometheus test
+ */
+public class OnlineParserSingleTest {
+
+    @Disabled // Disabled due to the fact that the URL is not reachable unless you have the Prometheus server running
+    @Test
+    void parseMetrics() throws Exception {
+        URL url = new URL("http://localhost:9090/metrics");
+        InputStream inputStream = url.openStream();
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "go_gc_duration_seconds");
+        assertNotNull(metricFamilyMap);
+    }
+
+    @Disabled // because unless you have already saved the locally tested files
+    @Test
+    void parseTestFile() throws Exception {
+        InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("test_file.txt");
+        assertNotNull(inputStream, "Failed to load test_file.txt resource");
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "windows_textfile_scrape_error");
+        assertNotNull(metricFamilyMap);
+    }
+
+
+    @Test
+    void parseMetricsOutOfOrder() throws Exception {
+        String str = """
+                # HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.
+                # TYPE go_gc_duration_seconds summary
+                jvm_gc_pause_seconds_count{action="end of major GC",cause="Metadata GC Threshold",} 1.0
+                jvm_gc_pause_seconds_sum{action="end of major GC",cause="Metadata GC Threshold",} 0.139
+                jvm_gc_pause_seconds_count{action="end of minor GC",cause="Metadata GC Threshold",} 1.0
+                jvm_gc_pause_seconds_sum{action="end of minor GC",cause="Metadata GC Threshold",} 0.02
+                jvm_gc_pause_seconds_count{action="end of minor GC",cause="Allocation Failure",} 5.0
+                jvm_gc_pause_seconds_sum{action="end of minor GC",cause="Allocation Failure",} 0.082
+                go_gc_duration_seconds{quantile="0"} 2.0209e-05
+                go_gc_duration_seconds{quantile="0"} 2.0209e-05
+                go_gc_duration_seconds{quantile="0.25"} 6.6917e-05
+                go_gc_duration_seconds{quantile="0.5"} -Inf
+                go_gc_duration_seconds{quantile="0.75"} +Inf
+                go_gc_duration_seconds{quantile="1"} NaN
+                go_gc_duration_seconds_sum 0.001134793
+                go_gc_duration_seconds_count 5
+                # HELP go_goroutines Number of goroutines that currently exist.
+                # TYPE go_goroutines gauge
+                go_goroutines 32
+                # HELP go_info Information about the Go environment.
+                # TYPE go_info gauge
+                go_info{version="go1.21.6"} 1
+                # HELP go_memstats_alloc_bytes Number of bytes allocated and still in use.
+                # TYPE go_memstats_alloc_bytes gauge
+                go_memstats_alloc_bytes 1.5716224e+07
+                # HELP go_memstats_alloc_bytes_total Total number of bytes allocated, even if freed.
+                # TYPE go_memstats_alloc_bytes_total counter
+                go_memstats_alloc_bytes_total 2.0707544e+07
+                # HELP go_memstats_buck_hash_sys_bytes Number of bytes used by the profiling bucket hash table.
+                # TYPE go_memstats_buck_hash_sys_bytes gauge
+                go_memstats_buck_hash_sys_bytes 1.457881e+06
+                # HELP go_memstats_frees_total Total number of frees.
+                # TYPE go_memstats_frees_total counter
+                go_memstats_frees_total 50438
+                # HELP go_memstats_gc_sys_bytes Number of bytes used for garbage collection system metadata.
+                # TYPE go_memstats_gc_sys_bytes gauge
+                go_memstats_gc_sys_bytes 4.614808e+06""";
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap1 = parseMetrics(inputStream, "go_memstats_buck_hash_sys_bytes");
+        assertNotNull(metricFamilyMap1);
+        MetricFamily metricFamily = metricFamilyMap1.get("go_memstats_buck_hash_sys_bytes");
+        assertNotNull(metricFamily);
+        assertNotNull(metricFamily.getName());
+        assertEquals("go_memstats_buck_hash_sys_bytes", metricFamily.getName());
+        assertEquals(1, metricFamily.getMetricList().size());
+        assertEquals(1457881.0, metricFamily.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithCrLf() throws Exception {
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\r\n"
+                + "jvm_gc_pause_seconds_count{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 1.0\r\n"
+                + "jvm_gc_pause_seconds_sum{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 0.139\r\n";
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_count");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_count");
+        assertEquals("jvm_gc_pause_seconds_count", metricFamily.getName());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\r\n"
+                + "jvm_gc_pause_seconds_count{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 1.0 1234567890\r\n"
+                + "jvm_gc_pause_seconds_sum{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 0.139 1234567890\r\n";
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily.getName());
+        assertEquals(0.139, metricFamily.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithLf() throws Exception {
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "jvm_gc_pause_seconds_count{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 1.0\n"
+                + "jvm_gc_pause_seconds_sum{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 0.139\n";
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_count");
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_count");
+        assertEquals("jvm_gc_pause_seconds_count", metricFamily.getName());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "jvm_gc_pause_seconds_count{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 1.0 1234567890\n"
+                + "jvm_gc_pause_seconds_sum{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 0.139 1234567890\n";
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily.getName());
+        assertEquals(0.139, metricFamily.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithoutFinalNewline() throws Exception {
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\r\n"
+                + "jvm_gc_pause_seconds_count{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 1.0\r\n"
+                + "jvm_gc_pause_seconds_sum{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 0.139";
+
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_count");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_count");
+        assertEquals("jvm_gc_pause_seconds_count", metricFamily.getName());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "jvm_gc_pause_seconds_count{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 1.0\n"
+                + "jvm_gc_pause_seconds_sum{action=\"end of major GC\",cause=\"Metadata GC Threshold\",} 0.139";
+
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily.getName());
+        assertEquals(0.139, metricFamily.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithEmptyLabelsAndCrLf() throws Exception {
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\r\n"
+                + "jvm_gc_pause_seconds_count 1.0\r\n"
+                + "jvm_gc_pause_seconds_sum{} 0.139";
+
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_count");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_count");
+        assertEquals("jvm_gc_pause_seconds_count", metricFamily.getName());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+        assertNotNull(metricFamilyMap);
+        MetricFamily metricFamily1 = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily1.getName());
+        assertEquals(0.139, metricFamily1.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithEmptyLabelsAndLf() throws Exception {
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "jvm_gc_pause_seconds_count 1.0\n"
+                + "jvm_gc_pause_seconds_sum{} 0.139";
+
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_count");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_count");
+        assertEquals("jvm_gc_pause_seconds_count", metricFamily.getName());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+        assertNotNull(metricFamilyMap);
+
+        MetricFamily metricFamily1 = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily1.getName());
+        assertEquals(0.139, metricFamily1.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithMixedLineEndings() throws Exception {
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "jvm_gc_pause_seconds_count 1.0\n"
+                + "jvm_gc_pause_seconds_sum{} 0.139\r\n";
+
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_count");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_count");
+        assertEquals("jvm_gc_pause_seconds_count", metricFamily.getName());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+        assertNotNull(metricFamilyMap);
+
+        MetricFamily metricFamily1 = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily1.getName());
+        assertEquals(0.139, metricFamily1.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithLfCrLineEnding() throws Exception {
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\n\r"
+                + "# TYPE go_gc_duration_seconds summary\n\r"
+                + "jvm_gc_pause_seconds_count 1.0\n\r"
+                + "jvm_gc_pause_seconds_sum{} 0.139\n\r";
+
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_count");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_count");
+        assertEquals("jvm_gc_pause_seconds_count", metricFamily.getName());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+        assertNotNull(metricFamilyMap);
+
+        MetricFamily metricFamily1 = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily1.getName());
+        assertEquals(0.139, metricFamily1.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithMixedLineEndingsIncludingLfCr() throws Exception {
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "jvm_gc_pause_seconds_count 1.0\n\r"
+                + "jvm_gc_pause_seconds_sum{} 0.139\r\n"
+                + "jvm_gc_pause_seconds_max{} 0.139\n";
+
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_count");
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_count");
+        assertEquals("jvm_gc_pause_seconds_count", metricFamily.getName());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+        assertNotNull(metricFamilyMap);
+        MetricFamily metricFamily1 = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily1.getName());
+        assertEquals(0.139, metricFamily1.getMetricList().get(0).getValue());
+
+        inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_max");
+        assertNotNull(metricFamilyMap);
+        MetricFamily metricFamily2 = metricFamilyMap.get("jvm_gc_pause_seconds_max");
+        assertEquals("jvm_gc_pause_seconds_max", metricFamily2.getName());
+        assertEquals(0.139, metricFamily2.getMetricList().get(0).getValue());
+    }
+
+    @Test
+    void testParseMetricsWithOnlyLfCr() throws Exception {
+        String str = "jvm_gc_pause_seconds_sum 42.0\n\r";
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "jvm_gc_pause_seconds_sum");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("jvm_gc_pause_seconds_sum");
+        assertEquals("jvm_gc_pause_seconds_sum", metricFamily.getName());
+        assertEquals(42.0, metricFamily.getMetricList().get(0).getValue());
+    }
+
+
+    @Test
+    void testParseMetricEscape1() throws Exception {
+        // test  escape '\\'
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "windows_service_info{display_name=\"\\\\Application Layer \nGateway Service\",name=\"alg\\\\\",process_id=\"0\",run_as=\"NT AUTHORITY\\\\LocalService\"} 1\n";
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "windows_service_info");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("windows_service_info");
+        assertEquals("windows_service_info", metricFamily.getName());
+        assertNotNull(metricFamily.getMetricList().get(0).getLabels());
+        assertEquals(4, metricFamily.getMetricList().get(0).getLabels().size());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        assertEquals("display_name", metricFamily.getMetricList().get(0).getLabels().get(0).getName());
+        assertEquals("\\Application Layer \nGateway Service", metricFamily.getMetricList().get(0).getLabels().get(0).getValue());
+
+        assertEquals("name", metricFamily.getMetricList().get(0).getLabels().get(1).getName());
+        assertEquals("alg\\", metricFamily.getMetricList().get(0).getLabels().get(1).getValue());
+
+        assertEquals("process_id", metricFamily.getMetricList().get(0).getLabels().get(2).getName());
+        assertEquals("0", metricFamily.getMetricList().get(0).getLabels().get(2).getValue());
+
+        assertEquals("run_as", metricFamily.getMetricList().get(0).getLabels().get(3).getName());
+        assertEquals("NT AUTHORITY\\LocalService", metricFamily.getMetricList().get(0).getLabels().get(3).getValue());
+    }
+
+    @Test
+    void testParseMetricEscape2() throws Exception {
+        // test  escape '\"'
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "windows_service_info{display_name=\"\\\"Application Layer \\\"Gateway Service\",name=\"alg\\\"\",process_id=\"0\",run_as=\"NT AUTHORITY\\\"LocalService\"} 1\n";
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "windows_service_info");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("windows_service_info");
+        assertEquals("windows_service_info", metricFamily.getName());
+        assertNotNull(metricFamily.getMetricList().get(0).getLabels());
+        assertEquals(4, metricFamily.getMetricList().get(0).getLabels().size());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        assertEquals("display_name", metricFamily.getMetricList().get(0).getLabels().get(0).getName());
+        assertEquals("\"Application Layer \"Gateway Service", metricFamily.getMetricList().get(0).getLabels().get(0).getValue());
+
+        assertEquals("name", metricFamily.getMetricList().get(0).getLabels().get(1).getName());
+        assertEquals("alg\"", metricFamily.getMetricList().get(0).getLabels().get(1).getValue());
+
+        assertEquals("process_id", metricFamily.getMetricList().get(0).getLabels().get(2).getName());
+        assertEquals("0", metricFamily.getMetricList().get(0).getLabels().get(2).getValue());
+
+        assertEquals("run_as", metricFamily.getMetricList().get(0).getLabels().get(3).getName());
+        assertEquals("NT AUTHORITY\"LocalService", metricFamily.getMetricList().get(0).getLabels().get(3).getValue());
+
+
+    }
+
+    @Test
+    void testParseMetricEscape3() throws Exception {
+        // test  escape '\n'
+        String str = "# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.\r\n"
+                + "# TYPE go_gc_duration_seconds summary\n"
+                + "windows_service_info{display_name=\"\nApplication Layer \nGateway Service\",name=\"alg\n\",process_id=\"0\",run_as=\"NT AUTHORITY\nLocalService\"} 1\n";
+        InputStream inputStream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
+
+        Map<String, MetricFamily> metricFamilyMap = parseMetrics(inputStream, "windows_service_info");
+
+        assertNotNull(metricFamilyMap);
+        assertEquals(1, metricFamilyMap.values().size());
+
+        MetricFamily metricFamily = metricFamilyMap.get("windows_service_info");
+        assertEquals("windows_service_info", metricFamily.getName());
+        assertNotNull(metricFamily.getMetricList().get(0).getLabels());
+        assertEquals(4, metricFamily.getMetricList().get(0).getLabels().size());
+        assertEquals(1.0, metricFamily.getMetricList().get(0).getValue());
+
+        assertEquals("display_name", metricFamily.getMetricList().get(0).getLabels().get(0).getName());
+        assertEquals("\nApplication Layer \nGateway Service", metricFamily.getMetricList().get(0).getLabels().get(0).getValue());
+
+        assertEquals("name", metricFamily.getMetricList().get(0).getLabels().get(1).getName());
+        assertEquals("alg\n", metricFamily.getMetricList().get(0).getLabels().get(1).getValue());
+
+        assertEquals("process_id", metricFamily.getMetricList().get(0).getLabels().get(2).getName());
+        assertEquals("0", metricFamily.getMetricList().get(0).getLabels().get(2).getValue());
+
+        assertEquals("run_as", metricFamily.getMetricList().get(0).getLabels().get(3).getName());
+        assertEquals("NT AUTHORITY\nLocalService", metricFamily.getMetricList().get(0).getLabels().get(3).getValue());
+    }
+
+    private Map<String, MetricFamily> parseMetrics(InputStream inputStream, String metric) throws IOException {
+        return OnlineParser.parseMetrics(inputStream, metric);
+    }
+}