Add Continuous Profiling to Unit Tests (#14506)

Uses a custom continusou jfr profiler.

Modifies the github actions for tests to do profiling only in the case
of jdk17, as the profiler requires jdk17+ to use the JFR streaming API
plus a few other language features in the code.

Continuous Profiling service is provided to the Apache Druid project
free of charge by Imply and any committer can request free access to
the UI.

.github/scripts/setup_test_profiling_env.sh

@@ -0,0 +1,44 @@
+# 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.
+
+#!/bin/bash
+
+set -e
+
+JAR_INPUT_FILE="jfr-profiler-1.0.0.jar"
+JAR_OUTPUT_FILE="jfr-profiler.jar"
+ENV_VAR="JFR_PROFILER_ARG_LINE"
+
+if [ "$#" -ne 5 ]; then
+    echo "usage: $0 <jdk_version> <run_id> <run_number> <run_attempt> <module>"
+fi
+
+if [[ "$1" == "17" ]];
+then
+  curl https://static.imply.io/cp/$JAR_INPUT_FILE -s -o $JAR_OUTPUT_FILE
+
+  echo $ENV_VAR=-javaagent:"$PWD"/$JAR_OUTPUT_FILE \
+  -Djfr.profiler.http.username=druid-ci \
+  -Djfr.profiler.http.password=w3Fb6PW8LIo849mViEkbgA== \
+  -Djfr.profiler.tags.project=druid \
+  -Djfr.profiler.tags.run_id=$2 \
+  -Djfr.profiler.tags.run_number=$3 \
+  -Djfr.profiler.tags.run_attempt=$4 \
+  -Djfr.profiler.tags.module=$5
+else
+  echo $ENV_VAR=\"\"
+fi
+
+

.github/scripts/unit_tests_script.sh

@@ -21,7 +21,8 @@ unset _JAVA_OPTIONS
 
 # Set MAVEN_OPTS for Surefire launcher.
 MAVEN_OPTS='-Xmx2500m' ${MVN} test -pl ${MAVEN_PROJECTS} \
-${MAVEN_SKIP} -Ddruid.generic.useDefaultValueForNull=${DRUID_USE_DEFAULT_VALUE_FOR_NULL}
+${MAVEN_SKIP} -Ddruid.generic.useDefaultValueForNull=${DRUID_USE_DEFAULT_VALUE_FOR_NULL} \
+-DjfrProfilerArgLine="${JFR_PROFILER_ARG_LINE}"
 sh -c "dmesg | egrep -i '(oom|out of memory|kill process|killed).*' -C 1 || exit 0"
 free -m
 ${MVN} -pl ${MAVEN_PROJECTS} jacoco:report || { echo "coverage_failure=false" >> "$GITHUB_ENV" && false; }

.github/workflows/reusable-unit-tests.yml

@@ -86,6 +86,11 @@ jobs:
             echo "DRUID_USE_DEFAULT_VALUE_FOR_NULL=true" >> $GITHUB_ENV
           fi
 
+      - name: test profiling
+        run: | 
+          ./.github/scripts/setup_test_profiling_env.sh ${{ inputs.jdk }} ${{ github.run_id }} \
+          ${{ github.run_number }} ${{ github.run_attempt }} ${{ inputs.module }} >> $GITHUB_ENV
+
       - name: fetch base branch for test coverage
         if: ${{ github.base_ref != '' }}
         run: |

pom.xml

@@ -145,6 +145,8 @@
              ref: https://github.com/mapstruct/mapstruct/pull/1241
              -->
          <jacocoArgLine />
+         <!--  used to enable continuous profiling of jdk17 unit tests in github actions  -->
+         <jfrProfilerArgLine></jfrProfilerArgLine>
     </properties>
 
     <modules>
@@ -1636,6 +1638,7 @@
                             -Ddruid.test.stupidPool.poison=true
                             <!--@TODO After fixing https://github.com/apache/druid/issues/4964 remove this parameter-->
                             -Ddruid.indexing.doubleStorage=double
+                            ${jfrProfilerArgLine}
                         </argLine>
                         <!-- Skip the tests which Surefire runs. Surefire runs the unit tests,
                              while its sister plugin, Failsafe, runs the "new" ITs. -->

processing/src/main/java/org/apache/druid/common/guava/GuavaUtils.java

@@ -75,12 +75,12 @@ public static <T extends Enum<T>> T getEnumIfPresent(final Class<T> enumClass, f
    * except will not explode if both arguments are null.
    */
   @Nullable
-  public static <T> T firstNonNull(@Nullable T arg1, @Nullable T arg2)
+  public static <T> T firstNonNull(@Nullable T lhs, @Nullable T rhs)
   {
-    if (arg1 == null) {
-      return arg2;
+    if (lhs == null) {
+      return rhs;
     }
-    return arg1;
+    return lhs;
   }
 
   /**