Revert "Fixes #635: Changing creation of service classes away from ex…

…plicit guice usage to avoid duplicate instantiation of DefaultPrometheusMetrics class. (#644)"

This reverts commit 9401c6e.

src/main/java/org/jenkinsci/plugins/prometheus/context/Context.java

@@ -0,0 +1,16 @@
+package org.jenkinsci.plugins.prometheus.context;
+
+import com.google.inject.AbstractModule;
+import hudson.Extension;
+import org.jenkinsci.plugins.prometheus.service.DefaultPrometheusMetrics;
+import org.jenkinsci.plugins.prometheus.service.PrometheusMetrics;
+
+@Extension
+public class Context extends AbstractModule {
+
+    @Override
+    public void configure() {
+        bind(PrometheusMetrics.class).to(DefaultPrometheusMetrics.class).in(com.google.inject.Singleton.class);
+    }
+
+}

src/main/java/org/jenkinsci/plugins/prometheus/rest/PrometheusAction.java

@@ -1,7 +1,7 @@
 package org.jenkinsci.plugins.prometheus.rest;
 
+import com.google.inject.Inject;
 import hudson.Extension;
-import hudson.ExtensionList;
 import hudson.model.UnprotectedRootAction;
 import hudson.util.HttpResponses;
 import io.prometheus.client.exporter.common.TextFormat;
@@ -15,7 +15,14 @@
 
 @Extension
 public class PrometheusAction implements UnprotectedRootAction {
-
+
+    private PrometheusMetrics prometheusMetrics;
+
+    @Inject
+    public void setPrometheusMetrics(PrometheusMetrics prometheusMetrics) {
+        this.prometheusMetrics = prometheusMetrics;
+    }
+
     @Override
     public String getIconFileName() {
         return null;
@@ -49,7 +56,6 @@ private boolean hasAccess() {
     }
 
     private HttpResponse prometheusResponse() {
-        PrometheusMetrics prometheusMetrics = ExtensionList.lookupSingleton(PrometheusMetrics.class);
         return (request, response, node) -> {
             response.setStatus(StaplerResponse.SC_OK);
             response.setContentType(TextFormat.CONTENT_TYPE_004);

src/main/java/org/jenkinsci/plugins/prometheus/service/DefaultPrometheusMetrics.java

@@ -1,6 +1,5 @@
 package org.jenkinsci.plugins.prometheus.service;
 
-import hudson.Extension;
 import hudson.ExtensionList;
 import hudson.init.InitMilestone;
 import hudson.init.Initializer;
@@ -9,24 +8,26 @@
 import io.prometheus.client.dropwizard.DropwizardExports;
 import io.prometheus.client.exporter.common.TextFormat;
 import io.prometheus.client.hotspot.DefaultExports;
+import java.io.IOException;
+import java.io.StringWriter;
+import java.util.concurrent.atomic.AtomicReference;
 import jenkins.metrics.api.Metrics;
-import org.jenkinsci.plugins.prometheus.*;
+import org.jenkinsci.plugins.prometheus.CodeCoverageCollector;
+import org.jenkinsci.plugins.prometheus.DiskUsageCollector;
+import org.jenkinsci.plugins.prometheus.ExecutorCollector;
+import org.jenkinsci.plugins.prometheus.JenkinsStatusCollector;
+import org.jenkinsci.plugins.prometheus.JobCollector;
 import org.jenkinsci.plugins.prometheus.config.disabledmetrics.FilteredMetricEnumeration;
 import org.jenkinsci.plugins.prometheus.util.JenkinsNodeBuildsSampleBuilder;
 import org.kohsuke.accmod.Restricted;
 import org.kohsuke.accmod.restrictions.NoExternalUse;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.IOException;
-import java.io.StringWriter;
-import java.util.concurrent.atomic.AtomicReference;
-
 @Restricted(NoExternalUse.class)
-@Extension
 public class DefaultPrometheusMetrics implements PrometheusMetrics {
 
-    private static final Logger LOGGER = LoggerFactory.getLogger(DefaultPrometheusMetrics.class);
+    private static final Logger logger = LoggerFactory.getLogger(DefaultPrometheusMetrics.class);
 
     private volatile boolean initialized = false;
     private volatile boolean initializing = false;
@@ -39,10 +40,10 @@ public DefaultPrometheusMetrics() {
     }
 
     @Initializer(after = InitMilestone.JOB_LOADED)
-    public void registerCollectors() {
+    public void init() {
         if (!initialized && !initializing) {
             initializing = true;
-            LOGGER.debug("Initializing...");
+            logger.debug("Initializing...");
             collectorRegistry.register(new JobCollector());
             collectorRegistry.register(new JenkinsStatusCollector());
             collectorRegistry.register(
@@ -66,14 +67,14 @@ public String getMetrics() {
     @Override
     public void collectMetrics() {
         if(!initialized) {
-            LOGGER.debug("Not initialized");
+            logger.debug("Not initialized");
             return;
         }
         try (StringWriter buffer = new StringWriter()) {
             TextFormat.write004(buffer, new FilteredMetricEnumeration(collectorRegistry.metricFamilySamples().asIterator()));
             cachedMetrics.set(buffer.toString());
         } catch (IOException e) {
-            LOGGER.debug("Unable to collect metrics");
+            logger.debug("Unable to collect metrics");
         }
     }
 }

src/main/java/org/jenkinsci/plugins/prometheus/service/PrometheusAsyncWorker.java

@@ -1,7 +1,7 @@
 package org.jenkinsci.plugins.prometheus.service;
 
+import com.google.inject.Inject;
 import hudson.Extension;
-import hudson.ExtensionList;
 import hudson.model.AsyncPeriodicWork;
 import hudson.model.TaskListener;
 import org.jenkinsci.plugins.prometheus.config.PrometheusConfiguration;
@@ -16,11 +16,16 @@ public class PrometheusAsyncWorker extends AsyncPeriodicWork {
 
     private static final Logger logger = LoggerFactory.getLogger(PrometheusAsyncWorker.class);
 
+    private PrometheusMetrics prometheusMetrics;
 
     public PrometheusAsyncWorker() {
         super("prometheus_async_worker");
     }
 
+    @Inject
+    public void setPrometheusMetrics(PrometheusMetrics prometheusMetrics) {
+        this.prometheusMetrics = prometheusMetrics;
+    }
 
     @Override
     public long getRecurrencePeriod() {
@@ -33,7 +38,6 @@ public long getRecurrencePeriod() {
     @Override
     public void execute(TaskListener taskListener) {
         logger.debug("Collecting prometheus metrics");
-        PrometheusMetrics prometheusMetrics = ExtensionList.lookupSingleton(PrometheusMetrics.class);
         prometheusMetrics.collectMetrics();
         logger.debug("Prometheus metrics collected successfully");
     }

src/main/java/org/jenkinsci/plugins/prometheus/service/PrometheusMetrics.java

@@ -1,8 +1,6 @@
 package org.jenkinsci.plugins.prometheus.service;
 
-import hudson.ExtensionPoint;
-
-public interface PrometheusMetrics extends ExtensionPoint {
+public interface PrometheusMetrics {
 
     String getMetrics();
 

src/test/java/org/jenkinsci/plugins/prometheus/context/ContextTest.java

@@ -0,0 +1,50 @@
+package org.jenkinsci.plugins.prometheus.context;
+
+import com.codahale.metrics.MetricRegistry;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import jenkins.metrics.api.Metrics;
+import jenkins.model.Jenkins;
+import org.jenkinsci.plugins.prometheus.config.PrometheusConfiguration;
+import org.jenkinsci.plugins.prometheus.service.DefaultPrometheusMetrics;
+import org.jenkinsci.plugins.prometheus.service.PrometheusMetrics;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+
+import static org.mockito.Mockito.*;
+
+public class ContextTest {
+
+    @Test
+    public void testCanInjectContext() {
+        try (MockedStatic<Jenkins> jenkinsStatic = mockStatic(Jenkins.class);
+             MockedStatic<PrometheusConfiguration> prometheusConfigurationStatic = mockStatic(PrometheusConfiguration.class);
+             MockedStatic<Metrics> metricsStatic = mockStatic(Metrics.class)) {
+            Jenkins mockedJenkins = mock(Jenkins.class);
+            jenkinsStatic.when(Jenkins::get).thenReturn(mockedJenkins);
+
+            MetricRegistry mockedMetrics = mock(MetricRegistry.class);
+            metricsStatic.when(Metrics::metricRegistry).thenReturn(mockedMetrics);
+
+            PrometheusConfiguration mockedPrometheusConfiguration = mock(PrometheusConfiguration.class);
+            when(mockedPrometheusConfiguration.getLabeledBuildParameterNamesAsArray()).thenReturn(new String[]{});
+            when(mockedPrometheusConfiguration.getDefaultNamespace()).thenReturn("default");
+            prometheusConfigurationStatic.when(PrometheusConfiguration::get).thenReturn(mockedPrometheusConfiguration);
+
+            Injector injector = Guice.createInjector(new Context());
+            PrometheusMetrics prometheusMetrics = injector.getInstance(PrometheusMetrics.class);
+
+            Assertions.assertNotNull(prometheusMetrics);
+            Assertions.assertEquals(DefaultPrometheusMetrics.class, prometheusMetrics.getClass());
+
+            PrometheusMetrics prometheusMetrics2 = injector.getInstance(PrometheusMetrics.class);
+
+            Assertions.assertEquals(prometheusMetrics, prometheusMetrics2, "Should be the same as it's a singleton!");
+
+
+        }
+
+    }
+
+}

src/test/java/org/jenkinsci/plugins/prometheus/rest/PrometheusActionTest.java

@@ -1,6 +1,5 @@
 package org.jenkinsci.plugins.prometheus.rest;
 
-import hudson.ExtensionList;
 import io.prometheus.client.exporter.common.TextFormat;
 import jenkins.metrics.api.Metrics;
 import jenkins.model.Jenkins;
@@ -92,24 +91,21 @@ public void shouldReturnMetrics() throws IOException, ServletException {
         PrometheusMetrics prometheusMetrics = mock(PrometheusMetrics.class);
         String responseBody = "testMetric";
         when(prometheusMetrics.getMetrics()).thenReturn(responseBody);
-        try (MockedStatic<ExtensionList> extensionListMockedStatic = mockStatic(ExtensionList.class)) {
-            extensionListMockedStatic.when(() -> ExtensionList.lookupSingleton(PrometheusMetrics.class)).thenReturn(prometheusMetrics);
-            StaplerRequest request = mock(StaplerRequest.class);
-            String url = "prometheus";
-            when(request.getRestOfPath()).thenReturn(url);
-
-            // when
-            HttpResponse actual = action.doDynamic(request);
-
-            // then
-            AssertStaplerResponse.from(actual)
-                    .call()
-                    .assertHttpStatus(HTTP_OK)
-                    .assertContentType(TextFormat.CONTENT_TYPE_004)
-                    .assertHttpHeader("Cache-Control", "must-revalidate,no-cache,no-store")
-                    .assertBody(responseBody);
-        }
+        action.setPrometheusMetrics(prometheusMetrics);
+        StaplerRequest request = mock(StaplerRequest.class);
+        String url = "prometheus";
+        when(request.getRestOfPath()).thenReturn(url);
+
+        // when
+        HttpResponse actual = action.doDynamic(request);
 
+        // then
+        AssertStaplerResponse.from(actual)
+            .call()
+            .assertHttpStatus(HTTP_OK)
+            .assertContentType(TextFormat.CONTENT_TYPE_004)
+            .assertHttpHeader("Cache-Control", "must-revalidate,no-cache,no-store")
+            .assertBody(responseBody);
     }
 
     private static class AssertStaplerResponse {

src/test/java/org/jenkinsci/plugins/prometheus/service/PrometheusAsyncWorkerTest.java

@@ -1,6 +1,5 @@
 package org.jenkinsci.plugins.prometheus.service;
 
-import hudson.ExtensionList;
 import org.jenkinsci.plugins.prometheus.config.PrometheusConfiguration;
 import org.junit.jupiter.api.Test;
 import org.jvnet.hudson.test.Issue;
@@ -21,15 +20,15 @@ public void shouldCollectMetrics() {
         // given
         PrometheusAsyncWorker asyncWorker = new PrometheusAsyncWorker();
         PrometheusMetrics metrics = new TestPrometheusMetrics();
-        try (MockedStatic<ExtensionList> extensionListMockedStatic = mockStatic(ExtensionList.class)) {
-            extensionListMockedStatic.when(() -> ExtensionList.lookupSingleton(PrometheusMetrics.class)).thenReturn(metrics);
-            // when
-            asyncWorker.execute(null);
+        asyncWorker.setPrometheusMetrics(metrics);
+
+        // when
+        asyncWorker.execute(null);
+
+        // then
+        String actual = metrics.getMetrics();
+        assertEquals("1", actual);
 
-            // then
-            String actual = metrics.getMetrics();
-            assertEquals("1", actual);
-        }
     }
     @Test
     public void testConvertSecondsToMillis() {