[hbase] branch branch-2 updated: HBASE-27435 Make Prometheus metrics queryable (#4879)

[meszibalu]

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meszibalu pushed a commit to branch branch-2
in repository https://gitbox.apache.org/repos/asf/hbase.git


The following commit(s) were added to refs/heads/branch-2 by this push:
     new 98d66828bd3 HBASE-27435 Make Prometheus metrics queryable (#4879)
98d66828bd3 is described below

commit 98d66828bd388c50544bf7c046fea124360ad31d
Author: Luca Kovács <kovacs.luca.ag...@gmail.com>
AuthorDate: Mon Dec 12 11:59:03 2022 +0100

    HBASE-27435 Make Prometheus metrics queryable (#4879)
    
    Signed-off-by: Balazs Meszaros <meszib...@apache.org>
---
 .../http/prometheus/PrometheusHadoopServlet.java   | 38 ++++++++++++----------
 .../http/prometheus/TestPrometheusServlet.java     |  2 +-
 2 files changed, 22 insertions(+), 18 deletions(-)

diff --git 
a/hbase-http/src/main/java/org/apache/hadoop/hbase/http/prometheus/PrometheusHadoopServlet.java
 
b/hbase-http/src/main/java/org/apache/hadoop/hbase/http/prometheus/PrometheusHadoopServlet.java
index db5952e2fa7..25bd57927d3 100644
--- 
a/hbase-http/src/main/java/org/apache/hadoop/hbase/http/prometheus/PrometheusHadoopServlet.java
+++ 
b/hbase-http/src/main/java/org/apache/hadoop/hbase/http/prometheus/PrometheusHadoopServlet.java
@@ -35,13 +35,13 @@ import org.apache.yetus.audience.InterfaceAudience;
 
 @InterfaceAudience.Private
 public class PrometheusHadoopServlet extends HttpServlet {
-
   private static final Pattern SPLIT_PATTERN =
     Pattern.compile("(?<=[a-z])(?=[A-Z])|(?<=[A-Z])(?=([A-Z][a-z]))|\\W|(_)+");
 
   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
throws IOException {
-    writeMetrics(resp.getWriter(), 
"true".equals(req.getParameter("description")));
+    writeMetrics(resp.getWriter(), 
"true".equals(req.getParameter("description")),
+      req.getParameter("qry"));
   }
 
   static String toPrometheusName(String metricRecordName, String metricName) {
@@ -57,7 +57,8 @@ public class PrometheusHadoopServlet extends HttpServlet {
    */
   @RestrictedApi(explanation = "Should only be called in tests or self", link 
= "",
       allowedOnPath = ".*/src/test/.*|.*/PrometheusHadoopServlet\\.java")
-  void writeMetrics(Writer writer, boolean desc) throws IOException {
+  void writeMetrics(Writer writer, boolean descriptionEnabled, String 
queryParam)
+    throws IOException {
     Collection<MetricsRecord> metricRecords = MetricsExportHelper.export();
     for (MetricsRecord metricsRecord : metricRecords) {
       for (AbstractMetric metrics : metricsRecord.metrics()) {
@@ -65,23 +66,26 @@ public class PrometheusHadoopServlet extends HttpServlet {
 
           String key = toPrometheusName(metricsRecord.name(), metrics.name());
 
-          if (desc) {
-            String description = metrics.description();
-            if (!description.isEmpty()) writer.append("# HELP 
").append(description).append('\n');
-          }
+          if (queryParam == null || key.contains(queryParam)) {
+
+            if (descriptionEnabled) {
+              String description = metrics.description();
+              if (!description.isEmpty()) writer.append("# HELP 
").append(description).append('\n');
+            }
 
-          writer.append("# TYPE ").append(key).append(" ")
-            
.append(metrics.type().toString().toLowerCase()).append('\n').append(key).append("{");
+            writer.append("# TYPE ").append(key).append(" ")
+              
.append(metrics.type().toString().toLowerCase()).append('\n').append(key).append("{");
 
-          /* add tags */
-          String sep = "";
-          for (MetricsTag tag : metricsRecord.tags()) {
-            String tagName = tag.name().toLowerCase();
-            
writer.append(sep).append(tagName).append("=\"").append(tag.value()).append("\"");
-            sep = ",";
+            /* add tags */
+            String sep = "";
+            for (MetricsTag tag : metricsRecord.tags()) {
+              String tagName = tag.name().toLowerCase();
+              
writer.append(sep).append(tagName).append("=\"").append(tag.value()).append("\"");
+              sep = ",";
+            }
+            writer.append("} ");
+            writer.append(metrics.value().toString()).append('\n');
           }
-          writer.append("} ");
-          writer.append(metrics.value().toString()).append('\n');
         }
       }
     }
diff --git 
a/hbase-http/src/test/java/org/apache/hadoop/hbase/http/prometheus/TestPrometheusServlet.java
 
b/hbase-http/src/test/java/org/apache/hadoop/hbase/http/prometheus/TestPrometheusServlet.java
index 0ca021bc12b..276a2b9ad29 100644
--- 
a/hbase-http/src/test/java/org/apache/hadoop/hbase/http/prometheus/TestPrometheusServlet.java
+++ 
b/hbase-http/src/test/java/org/apache/hadoop/hbase/http/prometheus/TestPrometheusServlet.java
@@ -61,7 +61,7 @@ public class TestPrometheusServlet {
     // WHEN
     PrometheusHadoopServlet prom2Servlet = new PrometheusHadoopServlet();
     // Test with no description
-    prom2Servlet.writeMetrics(writer, false);
+    prom2Servlet.writeMetrics(writer, false, null);
 
     // THEN
     String writtenMetrics = stream.toString(UTF_8.name());