add Checkstyle (#1199)

* add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> * add checkstyle Signed-off-by: Gregor Zeitlinger <[email protected]> --------- Signed-off-by: Gregor Zeitlinger <[email protected]>
prometheus · Nov 12, 2024 · c93e48c · c93e48c
1 parent d6572b7
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diff --git a/.editorconfig b/.editorconfig
@@ -0,0 +1,8 @@
+root = true
+
+[*]
+max_line_length = 100
+indent_size = 2
+
+[pom.xml]
+indent_size = 4
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -27,6 +27,7 @@ If you're getting errors when running tests:
 
 - Use `-Dspotless.check.skip=true` to skip the formatting check during development.
 - Use `-Dcoverage.skip=true` to skip the coverage check during development.
+- Use `-Dcheckstyle.skip=true` to skip the checkstyle check during development.
 - Use `-Dwarnings=-nowarn` to skip the warnings during development.
 
 ## Updating the Protobuf Java Classes

diff --git a/checkstyle-suppressions.xml b/checkstyle-suppressions.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+
+<!DOCTYPE suppressions PUBLIC
+  "-//Checkstyle//DTD SuppressionFilter Configuration 1.2//EN"
+  "https://checkstyle.org/dtds/suppressions_1_2.dtd">
+
+<suppressions>
+    <suppress checks="Javadoc" files="."/>
+</suppressions>
diff --git a/checkstyle.xml b/checkstyle.xml
diff --git a/examples/example-exemplars-tail-sampling/example-greeting-service/pom.xml b/examples/example-exemplars-tail-sampling/example-greeting-service/pom.xml
@@ -57,7 +57,7 @@
                         <configuration>
                             <transformers>
                                 <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
-                                    <mainClass>io.prometheus.metrics.examples.otel_exemplars.greeting.Main</mainClass>
+                                    <mainClass>io.prometheus.metrics.examples.otel.exemplars.greeting.Main</mainClass>
                                 </transformer>
                             </transformers>
                         </configuration>

diff --git a/...l_exemplars/greeting/GreetingServlet.java → ...l/exemplars/greeting/GreetingServlet.java b/...l_exemplars/greeting/GreetingServlet.java → ...l/exemplars/greeting/GreetingServlet.java
@@ -1,4 +1,4 @@
-package io.prometheus.metrics.examples.otel_exemplars.greeting;
+package io.prometheus.metrics.examples.otel.exemplars.greeting;
 
 import static io.prometheus.metrics.model.snapshots.Unit.nanosToSeconds;
 

diff --git a/...xamples/otel_exemplars/greeting/Main.java → ...xamples/otel/exemplars/greeting/Main.java b/...xamples/otel_exemplars/greeting/Main.java → ...xamples/otel/exemplars/greeting/Main.java
@@ -1,4 +1,4 @@
-package io.prometheus.metrics.examples.otel_exemplars.greeting;
+package io.prometheus.metrics.examples.otel.exemplars.greeting;
 
 import io.prometheus.metrics.exporter.servlet.jakarta.PrometheusMetricsServlet;
 import io.prometheus.metrics.instrumentation.jvm.JvmMetrics;

diff --git a/examples/example-exemplars-tail-sampling/example-hello-world-app/pom.xml b/examples/example-exemplars-tail-sampling/example-hello-world-app/pom.xml
@@ -57,7 +57,7 @@
                         <configuration>
                             <transformers>
                                 <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
-                                    <mainClass>io.prometheus.metrics.examples.otel_exemplars.app.Main</mainClass>
+                                    <mainClass>io.prometheus.metrics.examples.otel.exemplars.app.Main</mainClass>
                                 </transformer>
                             </transformers>
                         </configuration>

diff --git a/...otel_exemplars/app/HelloWorldServlet.java → ...otel/exemplars/app/HelloWorldServlet.java b/...otel_exemplars/app/HelloWorldServlet.java → ...otel/exemplars/app/HelloWorldServlet.java
@@ -1,4 +1,4 @@
-package io.prometheus.metrics.examples.otel_exemplars.app;
+package io.prometheus.metrics.examples.otel.exemplars.app;
 
 import static io.prometheus.metrics.model.snapshots.Unit.nanosToSeconds;
 import static java.net.http.HttpResponse.BodyHandlers.ofString;

diff --git a/...ics/examples/otel_exemplars/app/Main.java → ...ics/examples/otel/exemplars/app/Main.java b/...ics/examples/otel_exemplars/app/Main.java → ...ics/examples/otel/exemplars/app/Main.java
@@ -1,4 +1,4 @@
-package io.prometheus.metrics.examples.otel_exemplars.app;
+package io.prometheus.metrics.examples.otel.exemplars.app;
 
 import io.prometheus.metrics.exporter.servlet.jakarta.PrometheusMetricsServlet;
 import io.prometheus.metrics.instrumentation.jvm.JvmMetrics;

diff --git a/...src/main/java/io/prometheus/metrics/examples/opentelemetry/ManualCompleteMetricsTest.java b/...src/main/java/io/prometheus/metrics/examples/opentelemetry/ManualCompleteMetricsTest.java
@@ -59,7 +59,8 @@ public static void main(String[] args) throws Exception {
           histogram.labelValues("200").observe(random.nextGaussian());
       }
 
-      // Explicitly use a classic-only histogram to have an example of a classic histogram in OpenTelemetry
+      // Explicitly use a classic-only histogram to have an example of a classic
+      // histogram in OpenTelemetry
       Histogram classicHistogram = Histogram.newBuilder()
               .withName("request_size_bytes")
               .withHelp("Request size in Bytes")

diff --git a/...r-sample/src/main/java/io/prometheus/metrics/it/exporter/httpserver/HTTPServerSample.java b/...r-sample/src/main/java/io/prometheus/metrics/it/exporter/httpserver/HTTPServerSample.java
@@ -26,7 +26,10 @@ public static void main(String[] args) throws IOException, InterruptedException
 
     int port = parsePortOrExit(args[0]);
     Mode mode = parseModeOrExit(args[1]);
+    run(mode, port);
+  }
 
+  private static void run(Mode mode, int port) throws IOException, InterruptedException {
     Counter counter =
         Counter.builder()
             .name("uptime_seconds_total")

diff --git a/...main/java/io/prometheus/metrics/it/exporter/servlet/jetty/ExporterServletJettySample.java b/...main/java/io/prometheus/metrics/it/exporter/servlet/jetty/ExporterServletJettySample.java
@@ -29,7 +29,10 @@ public static void main(String[] args) throws Exception {
 
     int port = parsePortOrExit(args[0]);
     Mode mode = parseModeOrExit(args[1]);
+    run(mode, port);
+  }
 
+  private static void run(Mode mode, int port) throws Exception {
     Counter counter =
         Counter.builder()
             .name("uptime_seconds_total")

diff --git a/...in/java/io/prometheus/metrics/it/exporter/servlet/tomcat/ExporterServletTomcatSample.java b/...in/java/io/prometheus/metrics/it/exporter/servlet/tomcat/ExporterServletTomcatSample.java
@@ -32,7 +32,10 @@ public static void main(String[] args) throws LifecycleException, IOException {
 
     int port = parsePortOrExit(args[0]);
     Mode mode = parseModeOrExit(args[1]);
+    run(mode, port);
+  }
 
+  private static void run(Mode mode, int port) throws IOException, LifecycleException {
     Counter counter =
         Counter.builder()
             .name("uptime_seconds_total")

diff --git a/pom.xml b/pom.xml
@@ -21,6 +21,7 @@
         <otel.instrumentation.version>2.9.0-alpha</otel.instrumentation.version>
         <java.version>8</java.version>
         <jacoco.line-coverage>0.70</jacoco.line-coverage>
+        <checkstyle.skip>false</checkstyle.skip>
         <coverage.skip>false</coverage.skip>
         <warnings>-Werror</warnings>
     </properties>
@@ -224,6 +225,28 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <version>3.5.0</version>
+                <configuration>
+                    <consoleOutput>true</consoleOutput>
+                    <configLocation>google_checks.xml</configLocation>
+                    <configLocation>checkstyle.xml</configLocation>
+                    <violationSeverity>warning</violationSeverity>
+                    <failOnViolation>true</failOnViolation>
+                    <skip>${checkstyle.skip}</skip>
+                    <suppressionsLocation>checkstyle-suppressions.xml</suppressionsLocation>
+                    <excludes>**/generated/**,**/jmh_generated/*</excludes>
+                </configuration>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>

diff --git a/...s-metrics-core/src/main/java/io/prometheus/metrics/core/datapoints/StateSetDataPoint.java b/...s-metrics-core/src/main/java/io/prometheus/metrics/core/datapoints/StateSetDataPoint.java
@@ -14,12 +14,6 @@ public interface StateSetDataPoint extends DataPoint {
    */
   void setTrue(String state);
 
-  /**
-   * {@code state} must be one of the states from when the {@code StateSet} was created with {@link
-   * io.prometheus.metrics.core.metrics.StateSet.Builder#states(String...)}.
-   */
-  void setFalse(String state);
-
   /**
    * {@code state} must be one of the states from when the {@code StateSet} was created with {@link
    * io.prometheus.metrics.core.metrics.StateSet.Builder#states(Class)}.
@@ -28,6 +22,12 @@ default void setTrue(Enum<?> state) {
     setTrue(state.toString());
   }
 
+  /**
+   * {@code state} must be one of the states from when the {@code StateSet} was created with {@link
+   * io.prometheus.metrics.core.metrics.StateSet.Builder#states(String...)}.
+   */
+  void setFalse(String state);
+
   /**
    * {@code state} must be one of the states from when the {@code StateSet} was created with {@link
    * io.prometheus.metrics.core.metrics.StateSet.Builder#states(Class)}.

diff --git a/...heus-metrics-core/src/main/java/io/prometheus/metrics/core/exemplars/ExemplarSampler.java b/...heus-metrics-core/src/main/java/io/prometheus/metrics/core/exemplars/ExemplarSampler.java
@@ -130,6 +130,16 @@ private long doObserveSingleExemplar(double value) {
     return 0;
   }
 
+  private long doObserveSingleExemplar(double amount, Labels labels) {
+    long now = System.currentTimeMillis();
+    Exemplar current = customExemplars[0];
+    if (current == null
+        || now - current.getTimestampMillis() > config.getMinRetentionPeriodMillis()) {
+      return updateCustomExemplar(0, amount, labels, now);
+    }
+    return 0;
+  }
+
   private long doObserveWithUpperBounds(double value) {
     long now = System.currentTimeMillis();
     double[] upperBounds = config.getHistogramClassicUpperBounds();
@@ -212,16 +222,6 @@ private long doObserveWithExemplar(double amount, Labels labels) {
     }
   }
 
-  private long doObserveSingleExemplar(double amount, Labels labels) {
-    long now = System.currentTimeMillis();
-    Exemplar current = customExemplars[0];
-    if (current == null
-        || now - current.getTimestampMillis() > config.getMinRetentionPeriodMillis()) {
-      return updateCustomExemplar(0, amount, labels, now);
-    }
-    return 0;
-  }
-
   private long doObserveWithExemplarWithUpperBounds(double value, Labels labels) {
     long now = System.currentTimeMillis();
     double[] upperBounds = config.getHistogramClassicUpperBounds();

diff --git a/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/CKMSQuantiles.java b/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/CKMSQuantiles.java
@@ -26,6 +26,8 @@
 import java.util.LinkedList;
 import java.util.ListIterator;
 
+// CHECKSTYLE:OFF: checkstyle
+
 /**
  * Algorithm solving the "Targeted Quantile Problem" as described in "Effective Computation of
  * Biased Quantiles over Data Streams" by Cormode, Korn, Muthukrishnan, and Srivastava.
@@ -273,3 +275,5 @@ public String toString() {
     }
   }
 }
+
+// CHECKSTYLE:ON: checkstyle
diff --git a/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/CallbackMetric.java b/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/CallbackMetric.java
@@ -28,7 +28,8 @@ protected Labels makeLabels(String... labelValues) {
       if (labelValues == null) {
         throw new IllegalArgumentException(
             this.getClass().getSimpleName()
-                + " was created with label names, but the callback was called without label values.");
+                + " was created with label names, "
+                + "but the callback was called without label values.");
       }
       if (labelValues.length != labelNames.length) {
         throw new IllegalArgumentException(

diff --git a/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Counter.java b/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Counter.java
@@ -82,6 +82,15 @@ public CounterSnapshot collect() {
     return (CounterSnapshot) super.collect();
   }
 
+  @Override
+  protected CounterSnapshot collect(List<Labels> labels, List<DataPoint> metricData) {
+    List<CounterSnapshot.CounterDataPointSnapshot> data = new ArrayList<>(labels.size());
+    for (int i = 0; i < labels.size(); i++) {
+      data.add(metricData.get(i).collect(labels.get(i)));
+    }
+    return new CounterSnapshot(getMetadata(), data);
+  }
+
   @Override
   protected boolean isExemplarsEnabled() {
     return exemplarsEnabled;
@@ -96,15 +105,6 @@ protected DataPoint newDataPoint() {
     }
   }
 
-  @Override
-  protected CounterSnapshot collect(List<Labels> labels, List<DataPoint> metricData) {
-    List<CounterSnapshot.CounterDataPointSnapshot> data = new ArrayList<>(labels.size());
-    for (int i = 0; i < labels.size(); i++) {
-      data.add(metricData.get(i).collect(labels.get(i)));
-    }
-    return new CounterSnapshot(getMetadata(), data);
-  }
-
   static String stripTotalSuffix(String name) {
     if (name != null && (name.endsWith("_total") || name.endsWith(".total"))) {
       name = name.substring(0, name.length() - 6);

diff --git a/...us-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/CounterWithCallback.java b/...us-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/CounterWithCallback.java
@@ -15,7 +15,7 @@
  *
  * CounterWithCallback.builder()
  *         .name("classes_loaded_total")
- *         .help("The total number of classes that have been loaded since the JVM has started execution")
+ *         .help("The total number of classes since the JVM has started execution")
  *         .callback(callback -> callback.call(classLoadingMXBean.getLoadedClassCount()))
  *         .register();
  * }</pre>

diff --git a/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Histogram.java b/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Histogram.java
@@ -63,7 +63,7 @@ public class Histogram extends StatefulMetric<DistributionDataPoint, Histogram.D
     implements DistributionDataPoint {
 
   // nativeSchema == CLASSIC_HISTOGRAM indicates that this is a classic histogram only.
-  private final int CLASSIC_HISTOGRAM = Integer.MIN_VALUE;
+  private static final int CLASSIC_HISTOGRAM = Integer.MIN_VALUE;
 
   // NATIVE_BOUNDS is used to look up the native bucket index depending on the current schema.
   private static final double[][] NATIVE_BOUNDS;
@@ -152,7 +152,7 @@ private Histogram(Histogram.Builder builder, PrometheusProperties prometheusProp
     double min =
         getConfigProperty(properties, MetricsProperties::getHistogramNativeMinZeroThreshold);
     nativeMaxZeroThreshold =
-        max == builder.DEFAULT_NATIVE_MAX_ZERO_THRESHOLD && min > max ? min : max;
+        max == Builder.DEFAULT_NATIVE_MAX_ZERO_THRESHOLD && min > max ? min : max;
     nativeMinZeroThreshold = Math.min(min, nativeMaxZeroThreshold);
     nativeMaxBuckets =
         getConfigProperty(properties, MetricsProperties::getHistogramNativeMaxNumberOfBuckets);
@@ -447,9 +447,9 @@ private void maybeScaleDown(AtomicBoolean wasReset) {
             // Now we are in the synchronized block while new observations go into the buffer.
             // Check again if we need to limit the bucket size, because another thread might
             // have limited it in the meantime.
-            int nBuckets =
+            int numBuckets =
                 nativeBucketsForPositiveValues.size() + nativeBucketsForNegativeValues.size();
-            if (nBuckets <= nativeMaxBuckets || nativeSchema == -4) {
+            if (numBuckets <= nativeMaxBuckets || nativeSchema == -4) {
               return null;
             }
             if (maybeReset()) {
@@ -668,11 +668,11 @@ public static class Builder extends StatefulMetric.Builder<Histogram.Builder, Hi
     public static final double[] DEFAULT_CLASSIC_UPPER_BOUNDS =
         new double[] {.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10};
 
-    private final double DEFAULT_NATIVE_MIN_ZERO_THRESHOLD = Math.pow(2.0, -128);
-    private final double DEFAULT_NATIVE_MAX_ZERO_THRESHOLD = Math.pow(2.0, -128);
-    private final int DEFAULT_NATIVE_INITIAL_SCHEMA = 5;
-    private final int DEFAULT_NATIVE_MAX_NUMBER_OF_BUCKETS = 160;
-    private final long DEFAULT_NATIVE_RESET_DURATION_SECONDS = 0; // 0 means no reset
+    private static final double DEFAULT_NATIVE_MIN_ZERO_THRESHOLD = Math.pow(2.0, -128);
+    private static final double DEFAULT_NATIVE_MAX_ZERO_THRESHOLD = Math.pow(2.0, -128);
+    private static final int DEFAULT_NATIVE_INITIAL_SCHEMA = 5;
+    private static final int DEFAULT_NATIVE_MAX_NUMBER_OF_BUCKETS = 160;
+    private static final long DEFAULT_NATIVE_RESET_DURATION_SECONDS = 0; // 0 means no reset
 
     private Boolean nativeOnly;
     private Boolean classicOnly;

diff --git a/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/StateSet.java b/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/StateSet.java
@@ -76,16 +76,6 @@ public StateSetSnapshot collect() {
     return (StateSetSnapshot) super.collect();
   }
 
-  @Override
-  public void setTrue(String state) {
-    getNoLabels().setTrue(state);
-  }
-
-  @Override
-  public void setFalse(String state) {
-    getNoLabels().setFalse(state);
-  }
-
   @Override
   protected StateSetSnapshot collect(List<Labels> labels, List<DataPoint> metricDataList) {
     List<StateSetSnapshot.StateSetDataPointSnapshot> data = new ArrayList<>(labels.size());
@@ -97,6 +87,16 @@ protected StateSetSnapshot collect(List<Labels> labels, List<DataPoint> metricDa
     return new StateSetSnapshot(getMetadata(), data);
   }
 
+  @Override
+  public void setTrue(String state) {
+    getNoLabels().setTrue(state);
+  }
+
+  @Override
+  public void setFalse(String state) {
+    getNoLabels().setFalse(state);
+  }
+
   @Override
   protected DataPoint newDataPoint() {
     return new DataPoint();

diff --git a/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/StatefulMetric.java b/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/StatefulMetric.java
@@ -105,7 +105,8 @@ public D labelValues(String... labelValues) {
             getClass().getSimpleName()
                 + " "
                 + getMetadata().getName()
-                + " was created with label names, so you must call labelValues(...) when using it.");
+                + " was created with label names, so you must call labelValues(...)"
+                + " when using it.");
       } else {
         throw new IllegalArgumentException(
             "Expected " + labelNames.length + " label values, but got " + labelValues.length + ".");