make protobuf optional

Author: zeitlinger

prometheus-metrics-core/src/test/java/io/prometheus/metrics/core/metrics/CounterTest.java

@@ -6,9 +6,9 @@
 import static org.assertj.core.data.Offset.offset;
 
 import io.prometheus.metrics.core.exemplars.ExemplarSamplerConfigTestUtil;
-import io.prometheus.metrics.expositionformats.PrometheusProtobufWriter;
-import io.prometheus.metrics.expositionformats.ProtobufUtil;
 import io.prometheus.metrics.expositionformats.generated.com_google_protobuf_4_28_3.Metrics;
+import io.prometheus.metrics.expositionformats.internal.PrometheusProtobufWriterImpl;
+import io.prometheus.metrics.expositionformats.internal.ProtobufUtil;
 import io.prometheus.metrics.model.snapshots.CounterSnapshot;
 import io.prometheus.metrics.model.snapshots.Exemplar;
 import io.prometheus.metrics.model.snapshots.Label;
@@ -112,7 +112,8 @@ public void testTotalStrippedFromName() {
           "my_counter_seconds", "my.counter.seconds"
         }) {
       Counter counter = Counter.builder().name(name).unit(Unit.SECONDS).build();
-      Metrics.MetricFamily protobufData = new PrometheusProtobufWriter().convert(counter.collect());
+      Metrics.MetricFamily protobufData =
+          new PrometheusProtobufWriterImpl().convert(counter.collect());
       assertThat(ProtobufUtil.shortDebugString(protobufData))
           .isEqualTo(
               "name: \"my_counter_seconds_total\" type: COUNTER metric { counter { value: 0.0 } }");

prometheus-metrics-core/src/test/java/io/prometheus/metrics/core/metrics/HistogramTest.java

@@ -8,9 +8,9 @@
 import io.prometheus.metrics.core.datapoints.DistributionDataPoint;
 import io.prometheus.metrics.core.exemplars.ExemplarSamplerConfigTestUtil;
 import io.prometheus.metrics.expositionformats.OpenMetricsTextFormatWriter;
-import io.prometheus.metrics.expositionformats.PrometheusProtobufWriter;
-import io.prometheus.metrics.expositionformats.ProtobufUtil;
 import io.prometheus.metrics.expositionformats.generated.com_google_protobuf_4_28_3.Metrics;
+import io.prometheus.metrics.expositionformats.internal.PrometheusProtobufWriterImpl;
+import io.prometheus.metrics.expositionformats.internal.ProtobufUtil;
 import io.prometheus.metrics.model.snapshots.ClassicHistogramBucket;
 import io.prometheus.metrics.model.snapshots.Exemplar;
 import io.prometheus.metrics.model.snapshots.Exemplars;
@@ -89,7 +89,7 @@ private void run() throws NoSuchFieldException, IllegalAccessException {
         }
       }
       Metrics.MetricFamily protobufData =
-          new PrometheusProtobufWriter().convert(histogram.collect());
+          new PrometheusProtobufWriterImpl().convert(histogram.collect());
       String expectedWithMetadata =
           "name: \"test\" type: HISTOGRAM metric { histogram { " + expected + " } }";
       assertThat(ProtobufUtil.shortDebugString(protobufData))
@@ -940,7 +940,7 @@ public void testDefaults() throws IOException {
             + "# EOF\n";
 
     // protobuf
-    Metrics.MetricFamily protobufData = new PrometheusProtobufWriter().convert(snapshot);
+    Metrics.MetricFamily protobufData = new PrometheusProtobufWriterImpl().convert(snapshot);
     assertThat(ProtobufUtil.shortDebugString(protobufData)).isEqualTo(expectedProtobuf);
 
     // text

prometheus-metrics-core/src/test/java/io/prometheus/metrics/core/metrics/InfoTest.java

@@ -4,9 +4,9 @@
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
 import io.prometheus.metrics.expositionformats.OpenMetricsTextFormatWriter;
-import io.prometheus.metrics.expositionformats.PrometheusProtobufWriter;
-import io.prometheus.metrics.expositionformats.ProtobufUtil;
 import io.prometheus.metrics.expositionformats.generated.com_google_protobuf_4_28_3.Metrics;
+import io.prometheus.metrics.expositionformats.internal.PrometheusProtobufWriterImpl;
+import io.prometheus.metrics.expositionformats.internal.ProtobufUtil;
 import io.prometheus.metrics.model.snapshots.Labels;
 import io.prometheus.metrics.model.snapshots.MetricSnapshots;
 import io.prometheus.metrics.model.snapshots.Unit;
@@ -27,7 +27,8 @@ public void testInfoStrippedFromName() {
       for (String labelName : new String[] {"my.key", "my_key"}) {
         Info info = Info.builder().name(name).labelNames(labelName).build();
         info.addLabelValues("value");
-        Metrics.MetricFamily protobufData = new PrometheusProtobufWriter().convert(info.collect());
+        Metrics.MetricFamily protobufData =
+            new PrometheusProtobufWriterImpl().convert(info.collect());
         assertThat(ProtobufUtil.shortDebugString(protobufData))
             .isEqualTo(
                 "name: \"jvm_runtime_info\" type: GAUGE metric { label { name: \"my_key\" value: \"value\" } gauge { value: 1.0 } }");

prometheus-metrics-exporter-common/src/main/java/io/prometheus/metrics/exporter/common/PrometheusScrapeHandler.java

@@ -45,7 +45,7 @@ public PrometheusScrapeHandler(PrometheusProperties config, PrometheusRegistry r
     this.registry = registry;
     this.nameFilter = makeNameFilter(config.getExporterFilterProperties());
     supportedFormats = new ArrayList<>(Arrays.asList("openmetrics", "text"));
-    if (expositionFormats.getPrometheusProtobufWriter() != null) {
+    if (expositionFormats.getPrometheusProtobufWriter().isAvailable()) {
       supportedFormats.add("prometheus-protobuf");
     }
   }

prometheus-metrics-exporter-pushgateway/src/main/java/io/prometheus/metrics/exporter/pushgateway/PushGateway.java

@@ -6,7 +6,7 @@
 import io.prometheus.metrics.config.PrometheusProperties;
 import io.prometheus.metrics.config.PrometheusPropertiesException;
 import io.prometheus.metrics.expositionformats.ExpositionFormatWriter;
-import io.prometheus.metrics.expositionformats.ExpositionFormats;
+import io.prometheus.metrics.expositionformats.PrometheusProtobufWriter;
 import io.prometheus.metrics.expositionformats.PrometheusTextFormatWriter;
 import io.prometheus.metrics.model.registry.Collector;
 import io.prometheus.metrics.model.registry.MultiCollector;
@@ -81,14 +81,17 @@ private PushGateway(
     this.requestHeaders = Collections.unmodifiableMap(new HashMap<>(requestHeaders));
     this.connectionFactory = connectionFactory;
     writer = getWriter(format);
+    if (!writer.isAvailable()) {
+      throw new RuntimeException(writer.getClass() + " is not available");
+    }
   }
 
   private ExpositionFormatWriter getWriter(Format format) {
     if (format == Format.PROMETHEUS_TEXT) {
       return new PrometheusTextFormatWriter(false);
     } else {
       // use reflection to avoid a compile-time dependency on the expositionformats module
-      return ExpositionFormats.createProtobufWriter();
+      return new PrometheusProtobufWriter();
     }
   }
 

…ionformats/PrometheusProtobufWriter.java …ternal/PrometheusProtobufWriterImpl.javaprometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusProtobufWriter.java renamed to prometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/internal/PrometheusProtobufWriterImpl.java prometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusProtobufWriter.java renamed to prometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/internal/PrometheusProtobufWriterImpl.java

@@ -1,8 +1,9 @@
-package io.prometheus.metrics.expositionformats;
+package io.prometheus.metrics.expositionformats.internal;
 
-import static io.prometheus.metrics.expositionformats.ProtobufUtil.timestampFromMillis;
+import static io.prometheus.metrics.expositionformats.internal.ProtobufUtil.timestampFromMillis;
 
 import com.google.protobuf.TextFormat;
+import io.prometheus.metrics.expositionformats.ExpositionFormatWriter;
 import io.prometheus.metrics.expositionformats.generated.com_google_protobuf_4_28_3.Metrics;
 import io.prometheus.metrics.model.snapshots.ClassicHistogramBuckets;
 import io.prometheus.metrics.model.snapshots.CounterSnapshot;
@@ -24,30 +25,16 @@
 import java.io.IOException;
 import java.io.OutputStream;
 
-/**
- * Write the Prometheus protobuf format as defined in <a
- * href="https://github.com/prometheus/client_model/tree/master/io/prometheus/client">github.com/prometheus/client_model</a>.
- *
- * <p>As of today, this is the only exposition format that supports native histograms.
- */
-public class PrometheusProtobufWriter implements ExpositionFormatWriter {
-
-  public static final String CONTENT_TYPE =
-      "application/vnd.google.protobuf; proto=io.prometheus.client.MetricFamily; encoding=delimited";
+public class PrometheusProtobufWriterImpl implements ExpositionFormatWriter {
 
   @Override
   public boolean accepts(String acceptHeader) {
-    if (acceptHeader == null) {
-      return false;
-    } else {
-      return acceptHeader.contains("application/vnd.google.protobuf")
-          && acceptHeader.contains("proto=io.prometheus.client.MetricFamily");
-    }
+    throw new IllegalStateException("use PrometheusProtobufWriter instead");
   }
 
   @Override
   public String getContentType() {
-    return CONTENT_TYPE;
+    throw new IllegalStateException("use PrometheusProtobufWriter instead");
   }
 
   @Override

…rics/expositionformats/ProtobufUtil.java …sitionformats/internal/ProtobufUtil.javaprometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/ProtobufUtil.java renamed to prometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/internal/ProtobufUtil.java prometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/ProtobufUtil.java renamed to prometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/internal/ProtobufUtil.java

@@ -1,4 +1,4 @@
-package io.prometheus.metrics.expositionformats;
+package io.prometheus.metrics.expositionformats.internal;
 
 import com.google.protobuf.MessageOrBuilder;
 import com.google.protobuf.TextFormat;

prometheus-metrics-exposition-formats/src/test/java/io/prometheus/metrics/expositionformats/ExpositionFormatsTest.java

@@ -3,6 +3,8 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 import io.prometheus.metrics.expositionformats.generated.com_google_protobuf_4_28_3.Metrics;
+import io.prometheus.metrics.expositionformats.internal.PrometheusProtobufWriterImpl;
+import io.prometheus.metrics.expositionformats.internal.ProtobufUtil;
 import io.prometheus.metrics.model.snapshots.ClassicHistogramBuckets;
 import io.prometheus.metrics.model.snapshots.CounterSnapshot;
 import io.prometheus.metrics.model.snapshots.CounterSnapshot.CounterDataPointSnapshot;
@@ -2658,7 +2660,7 @@ private void assertPrometheusTextWithoutCreated(String expected, MetricSnapshot
   }
 
   private void assertPrometheusProtobuf(String expected, MetricSnapshot snapshot) {
-    PrometheusProtobufWriter writer = new PrometheusProtobufWriter();
+    PrometheusProtobufWriterImpl writer = new PrometheusProtobufWriterImpl();
     Metrics.MetricFamily protobufData = writer.convert(snapshot);
     String actual = ProtobufUtil.shortDebugString(protobufData);
     assertThat(actual).isEqualTo(expected);

prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/ExpositionFormatWriter.java

@@ -22,4 +22,11 @@ default String toDebugString(MetricSnapshots metricSnapshots) {
   }
 
   String getContentType();
+
+  /**
+   * Returns true if the writer is available. If false, the writer will throw an exception if used.
+   */
+  default boolean isAvailable() {
+    return true;
+  }
 }

prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/ExpositionFormats.java

@@ -2,18 +2,17 @@
 
 import io.prometheus.metrics.config.ExporterProperties;
 import io.prometheus.metrics.config.PrometheusProperties;
-import javax.annotation.Nullable;
 
 public class ExpositionFormats {
 
-  @Nullable private final ExpositionFormatWriter prometheusProtobufWriter;
-  private final ExpositionFormatWriter prometheusTextFormatWriter;
-  private final ExpositionFormatWriter openMetricsTextFormatWriter;
+  private final PrometheusProtobufWriter prometheusProtobufWriter;
+  private final PrometheusTextFormatWriter prometheusTextFormatWriter;
+  private final OpenMetricsTextFormatWriter openMetricsTextFormatWriter;
 
   private ExpositionFormats(
-      ExpositionFormatWriter prometheusProtobufWriter,
-      ExpositionFormatWriter prometheusTextFormatWriter,
-      ExpositionFormatWriter openMetricsTextFormatWriter) {
+      PrometheusProtobufWriter prometheusProtobufWriter,
+      PrometheusTextFormatWriter prometheusTextFormatWriter,
+      OpenMetricsTextFormatWriter openMetricsTextFormatWriter) {
     this.prometheusProtobufWriter = prometheusProtobufWriter;
     this.prometheusTextFormatWriter = prometheusTextFormatWriter;
     this.openMetricsTextFormatWriter = openMetricsTextFormatWriter;
@@ -25,25 +24,12 @@ public static ExpositionFormats init() {
 
   public static ExpositionFormats init(ExporterProperties properties) {
     return new ExpositionFormats(
-        createProtobufWriter(),
+        new PrometheusProtobufWriter(),
         new PrometheusTextFormatWriter(properties.getIncludeCreatedTimestamps()),
         new OpenMetricsTextFormatWriter(
             properties.getIncludeCreatedTimestamps(), properties.getExemplarsOnAllMetricTypes()));
   }
 
-  @Nullable
-  public static ExpositionFormatWriter createProtobufWriter() {
-    try {
-      return Class.forName("io.prometheus.metrics.expositionformats.PrometheusProtobufWriter")
-          .asSubclass(ExpositionFormatWriter.class)
-          .getDeclaredConstructor()
-          .newInstance();
-    } catch (Exception e) {
-      // not in classpath
-      return null;
-    }
-  }
-
   public ExpositionFormatWriter findWriter(String acceptHeader) {
     if (prometheusProtobufWriter.accepts(acceptHeader)) {
       return prometheusProtobufWriter;
@@ -54,15 +40,15 @@ public ExpositionFormatWriter findWriter(String acceptHeader) {
     return prometheusTextFormatWriter;
   }
 
-  public ExpositionFormatWriter getPrometheusProtobufWriter() {
+  public PrometheusProtobufWriter getPrometheusProtobufWriter() {
     return prometheusProtobufWriter;
   }
 
-  public ExpositionFormatWriter getPrometheusTextFormatWriter() {
+  public PrometheusTextFormatWriter getPrometheusTextFormatWriter() {
     return prometheusTextFormatWriter;
   }
 
-  public ExpositionFormatWriter getOpenMetricsTextFormatWriter() {
+  public OpenMetricsTextFormatWriter getOpenMetricsTextFormatWriter() {
     return openMetricsTextFormatWriter;
   }
 }