[FLINK-37601] Remove Unirest dependency in PrometheusReporterTest (#26387)

* [FLINK-37601] remove Unirest dependency and use default HTTP library

Author: r-sidd

flink-metrics/flink-metrics-prometheus/pom.xml

@@ -100,12 +100,6 @@ under the License.
 			<artifactId>flink-test-utils-junit</artifactId>
 		</dependency>
 
-		<dependency>
-			<groupId>com.mashape.unirest</groupId>
-			<artifactId>unirest-java</artifactId>
-			<version>1.4.9</version>
-			<scope>test</scope>
-		</dependency>
 	</dependencies>
 
 	<build>

flink-metrics/flink-metrics-prometheus/src/test/java/org/apache/flink/metrics/prometheus/PrometheusReporterTaskScopeTest.java

@@ -27,11 +27,11 @@
 import org.apache.flink.metrics.util.TestMeter;
 import org.apache.flink.util.PortRange;
 
-import com.mashape.unirest.http.exceptions.UnirestException;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import java.io.IOException;
 import java.util.Arrays;
 
 import static org.apache.flink.metrics.prometheus.PrometheusReporterTest.pollMetrics;
@@ -126,7 +126,8 @@ void metersCanBeAddedSeveralTimesIfTheyDifferInLabels() {
     }
 
     @Test
-    void histogramsCanBeAddedSeveralTimesIfTheyDifferInLabels() throws UnirestException {
+    void histogramsCanBeAddedSeveralTimesIfTheyDifferInLabels()
+            throws IOException, InterruptedException {
         TestHistogram histogram1 = new TestHistogram();
         histogram1.setCount(1);
         TestHistogram histogram2 = new TestHistogram();
@@ -135,7 +136,7 @@ void histogramsCanBeAddedSeveralTimesIfTheyDifferInLabels() throws UnirestExcept
         reporter.notifyOfAddedMetric(histogram1, METRIC_NAME, metricGroup1);
         reporter.notifyOfAddedMetric(histogram2, METRIC_NAME, metricGroup2);
 
-        final String exportedMetrics = pollMetrics(reporter.getPort()).getBody();
+        final String exportedMetrics = pollMetrics(reporter.getPort()).body();
         assertThat(exportedMetrics).contains("label2=\"value1_2\",} 1.0");
         assertThat(exportedMetrics).contains("label2=\"value2_2\",} 2.0");
 

flink-metrics/flink-metrics-prometheus/src/test/java/org/apache/flink/metrics/prometheus/PrometheusReporterTest.java

@@ -29,13 +29,15 @@
 import org.apache.flink.metrics.util.TestMeter;
 import org.apache.flink.util.PortRange;
 
-import com.mashape.unirest.http.HttpResponse;
-import com.mashape.unirest.http.Unirest;
-import com.mashape.unirest.http.exceptions.UnirestException;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
@@ -58,6 +60,7 @@ class PrometheusReporterTest {
     private static final String DEFAULT_LABELS = "{" + DIMENSIONS + ",}";
     private static final String SCOPE_PREFIX =
             PrometheusReporter.SCOPE_PREFIX + LOGICAL_SCOPE + PrometheusReporter.SCOPE_SEPARATOR;
+    private static final HttpClient HTTP_CLIENT = HttpClient.newHttpClient();
 
     private static final PortRangeProvider portRangeProvider = new PortRangeProvider();
 
@@ -85,45 +88,46 @@ void teardown() throws Exception {
      * {@link io.prometheus.client.Counter} may not decrease, so report {@link Counter} as {@link
      * io.prometheus.client.Gauge}.
      *
-     * @throws UnirestException Might be thrown on HTTP problems.
+     * @throws IOException Might be thrown on I/O problems.
+     * @throws InterruptedException Might be thrown if the thread is interrupted.
      */
     @Test
-    void counterIsReportedAsPrometheusGauge() throws UnirestException {
+    void counterIsReportedAsPrometheusGauge() throws IOException, InterruptedException {
         Counter testCounter = new SimpleCounter();
         testCounter.inc(7);
 
         assertThatGaugeIsExported(testCounter, "testCounter", "7.0");
     }
 
     @Test
-    void gaugeIsReportedAsPrometheusGauge() throws UnirestException {
+    void gaugeIsReportedAsPrometheusGauge() throws IOException, InterruptedException {
         Gauge<Integer> testGauge = () -> 1;
 
         assertThatGaugeIsExported(testGauge, "testGauge", "1.0");
     }
 
     @Test
-    void nullGaugeDoesNotBreakReporter() throws UnirestException {
+    void nullGaugeDoesNotBreakReporter() throws IOException, InterruptedException {
         Gauge<Integer> testGauge = () -> null;
 
         assertThatGaugeIsExported(testGauge, "testGauge", "0.0");
     }
 
     @Test
-    void meterRateIsReportedAsPrometheusGauge() throws UnirestException {
+    void meterRateIsReportedAsPrometheusGauge() throws IOException, InterruptedException {
         Meter testMeter = new TestMeter();
 
         assertThatGaugeIsExported(testMeter, "testMeter", "5.0");
     }
 
     private void assertThatGaugeIsExported(Metric metric, String name, String expectedValue)
-            throws UnirestException {
+            throws IOException, InterruptedException {
         assertThat(addMetricAndPollResponse(metric, name))
                 .contains(createExpectedPollResponse(name, "", "gauge", expectedValue));
     }
 
     @Test
-    void histogramIsReportedAsPrometheusSummary() throws UnirestException {
+    void histogramIsReportedAsPrometheusSummary() throws IOException, InterruptedException {
         Histogram testHistogram = new TestHistogram();
 
         String histogramName = "testHistogram";
@@ -152,7 +156,8 @@ void histogramIsReportedAsPrometheusSummary() throws UnirestException {
      * name still exist.
      */
     @Test
-    void metricIsRemovedWhileOtherMetricsWithSameNameExist() throws UnirestException {
+    void metricIsRemovedWhileOtherMetricsWithSameNameExist()
+            throws IOException, InterruptedException {
         String metricName = "metric";
 
         Counter metric1 = new SimpleCounter();
@@ -168,7 +173,7 @@ void metricIsRemovedWhileOtherMetricsWithSameNameExist() throws UnirestException
         reporter.notifyOfAddedMetric(metric2, metricName, metricGroup2);
         reporter.notifyOfRemovedMetric(metric1, metricName, metricGroup);
 
-        String response = pollMetrics(reporter.getPort()).getBody();
+        String response = pollMetrics(reporter.getPort()).body();
 
         assertThat(response).contains("some_value").doesNotContain(labelValueThatShouldBeRemoved);
     }
@@ -239,13 +244,18 @@ void canStartTwoReportersWhenUsingPortRange() {
     }
 
     private String addMetricAndPollResponse(Metric metric, String metricName)
-            throws UnirestException {
+            throws IOException, InterruptedException {
         reporter.notifyOfAddedMetric(metric, metricName, metricGroup);
-        return pollMetrics(reporter.getPort()).getBody();
+        return pollMetrics(reporter.getPort()).body();
     }
 
-    static HttpResponse<String> pollMetrics(int port) throws UnirestException {
-        return Unirest.get("http://localhost:" + port + "/metrics").asString();
+    static HttpResponse<String> pollMetrics(int port) throws IOException, InterruptedException {
+        HttpRequest request =
+                HttpRequest.newBuilder()
+                        .uri(URI.create("http://localhost:" + port + "/metrics"))
+                        .GET()
+                        .build();
+        return HTTP_CLIENT.send(request, HttpResponse.BodyHandlers.ofString());
     }
 
     private static String createExpectedPollResponse(