make Protobuf optional

.github/workflows/build.yml

@@ -25,7 +25,6 @@ jobs:
           PROTO_GENERATION: true
           REQUIRE_PROTO_UP_TO_DATE: true
         run: |
-          echo "Java version: $(java -version) in $(which java), Maven version: $(mvn -v)"
-          echo "JAVA_HOME: $JAVA_HOME"
+          mvn -v
           ./mvnw clean install
           ./mvnw javadoc:javadoc -P javadoc # just to check if javadoc is generated

.github/workflows/native-tests.yml

@@ -0,0 +1,21 @@
+name: GraalVM Native Tests
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  native-tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: graalvm
+          cache: 'maven'
+      - name: Run the Maven verify phase
+        run: ./scripts/run-native-tests.sh

.github/workflows/release.yml

@@ -28,7 +28,7 @@ jobs:
           cache: 'maven'
 
       - name: Build with Maven
-        run: mvn -B package -P release -Dmaven.test.skip=true
+        run: ./scripts/build-release.sh ${{ github.ref_name }}
 
       - name: Set up Apache Maven Central
         uses: actions/setup-java@v4

RELEASING.md

@@ -1,13 +1,3 @@
-## Update Version
-
-In a new PR, update the version in `pom.xml` using 
-
-```shell
-mvn versions:set -DnewVersion=<VERSION>
-```
-
-Commit the changes and open a PR.
-
 ## Create a Release 
 
 1. Go to https://github.com/prometheus/client_java/releases

docs/content/exporters/formats.md

@@ -11,16 +11,35 @@ All exporters the following exposition formats:
 
 Moreover, gzip encoding is supported for each of these formats.
 
-Scraping with a Prometheus server
----------------------------------
+## Scraping with a Prometheus server
 
 The Prometheus server sends an `Accept` header to specify which format is requested. By default, the Prometheus server will scrape OpenMetrics text format with gzip encoding. If the Prometheus server is started with `--enable-feature=native-histograms`, it will scrape Prometheus protobuf format instead.
 
-Viewing with a Web Browser
---------------------------
+## Viewing with a Web Browser
 
 If you view the `/metrics` endpoint with your Web browser you will see Prometheus text format. For quick debugging of the other formats, exporters provide a `debug` URL parameter:
 
 * `/metrics?debug=openmetrics`: View OpenMetrics text format.
 * `/metrics?debug=text`: View Prometheus text format.
 * `/metrics?debug=prometheus-protobuf`: View a text representation of the Prometheus protobuf format.
+
+## Exclude protobuf exposition format
+
+You can exclude the protobuf exposition format by including the
+`prometheus-metrics-exposition-textformats` module and excluding the
+`prometheus-metrics-exposition-formats` module in your build file.
+
+For example, in Maven:
+
+```xml
+<dependency>
+    <groupId>io.prometheus</groupId>
+    <artifactId>prometheus-metrics-exporter-httpserver</artifactId>
+    <exclusions>
+        <exclusion>
+            <groupId>io.prometheus</groupId>
+            <artifactId>prometheus-metrics-exposition-formats</artifactId>
+        </exclusion>
+    </exclusions>
+</dependency>
+```

docs/content/getting-started/quickstart.md

@@ -45,6 +45,14 @@ implementation 'io.prometheus:prometheus-metrics-exporter-httpserver:$version'
 
 There are alternative exporters as well, for example if you are using a Servlet container like Tomcat or Undertow you might want to use `prometheus-exporter-servlet-jakarta` rather than a standalone HTTP server.
 
+{{< hint type=note >}}
+
+If you do not use the protobuf exposition format, you can 
+[exclude](../../exporters/formats#exclude-protobuf-exposition-format)
+it from the dependencies. 
+
+{{< /hint >}}
+
 # Dependency management
 
 A Bill of Material

docs/content/internals/model.md

@@ -7,25 +7,23 @@ The illustration below shows the internal architecture of the Prometheus Java cl
 
 ![Internal architecture of the Prometheus Java client library](/client_java/images/model.png)
 
-prometheus-metrics-core
------------------------
+## prometheus-metrics-core
 
 This is the user facing metrics library, implementing the core metric types, like [Counter](/client_java/api/io/prometheus/metrics/core/metrics/Counter.html), [Gauge](/client_java/api/io/prometheus/metrics/core/metrics/Gauge.html) [Histogram](/client_java/api/io/prometheus/metrics/core/metrics/Histogram.html), and so on.
 
 All metric types implement the [Collector](/client_java/api/io/prometheus/metrics/model/registry/Collector.html) interface, i.e. they provide a [collect()](/client_java/api/io/prometheus/metrics/model/registry/Collector.html#collect()) method to produce snapshots.
 
-prometheus-metrics-model
-------------------------
+## prometheus-metrics-model
 
 The model is an internal library, implementing read-only immutable snapshots. These snapshots are returned by the [Collector.collect()](/client_java/api/io/prometheus/metrics/model/registry/Collector.html#collect()) method.
 
 There is no need for users to use `prometheus-metrics-model` directly. Users should use the API provided by `prometheus-metrics-core`, which includes the core metrics as well as callback metrics.
 
 However, maintainers of 3rd party metrics libraries might want to use `prometheus-metrics-model` if they want to add Prometheus exposition formats to their metrics library.
 
-exporters and exposition formats
---------------------------------
+## Exporters and exposition formats
 
 The `prometheus-metrics-exposition-formats` module converts snapshots to Prometheus exposition formats, like text format, OpenMetrics text format, or Prometheus protobuf format.
 
 The exporters like `prometheus-metrics-exporter-httpserver` or `prometheus-metrics-exporter-servlet-jakarta` use this to convert snapshots into the right format depending on the `Accept` header in the scrape request.
+

integration-tests/it-common/pom.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
     <parent>
@@ -11,11 +12,18 @@
     <artifactId>it-common</artifactId>
 
     <name>Integration Tests - Common Utilities</name>
-    <url>http://github.com/prometheus/client_java</url>
     <description>
         Common utilities for integration tests
     </description>
 
+    <dependencies>
+        <dependency>
+            <groupId>io.prometheus</groupId>
+            <artifactId>prometheus-metrics-exposition-formats</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+    </dependencies>
+
     <build>
         <testResources>
             <testResource>

integration-tests/it-common/src/test/java/io/prometheus/client/it/common/ExporterTest.java

@@ -0,0 +1,158 @@
+package io.prometheus.client.it.common;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
+
+import io.prometheus.metrics.expositionformats.generated.com_google_protobuf_4_28_3.Metrics;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.zip.GZIPInputStream;
+import org.apache.commons.io.IOUtils;
+import org.junit.jupiter.api.AfterEach;
+import org.testcontainers.containers.BindMode;
+import org.testcontainers.containers.GenericContainer;
+
+public abstract class ExporterTest {
+  private final GenericContainer<?> sampleAppContainer;
+  private final Volume sampleAppVolume;
+  protected final String sampleApp;
+
+  public ExporterTest(String sampleApp) throws IOException, URISyntaxException {
+    this.sampleApp = sampleApp;
+    this.sampleAppVolume =
+        Volume.create("it-exporter")
+            .copy("../../it-" + sampleApp + "/target/" + sampleApp + ".jar");
+    this.sampleAppContainer =
+        new GenericContainer<>("openjdk:17")
+            .withFileSystemBind(sampleAppVolume.getHostPath(), "/app", BindMode.READ_ONLY)
+            .withWorkingDirectory("/app")
+            .withLogConsumer(LogConsumer.withPrefix(sampleApp))
+            .withExposedPorts(9400);
+  }
+
+  // @BeforeEach?
+  protected void start() {
+    start("success");
+  }
+
+  protected void start(String outcome) {
+    sampleAppContainer
+        .withCommand("java", "-jar", "/app/" + sampleApp + ".jar", "9400", outcome)
+        .start();
+  }
+
+  @AfterEach
+  public void tearDown() throws IOException {
+    sampleAppContainer.stop();
+    sampleAppVolume.remove();
+  }
+
+  public static void assertContentType(String expected, String actual) {
+    if (!expected.replace(" ", "").equals(actual)) {
+      assertThat(actual).isEqualTo(expected);
+    }
+  }
+
+  protected Response scrape(String method, String queryString, String... requestHeaders)
+      throws IOException {
+    return scrape(
+        method,
+        new URL(
+            "http://localhost:"
+                + sampleAppContainer.getMappedPort(9400)
+                + "/metrics?"
+                + queryString),
+        requestHeaders);
+  }
+
+  public static Response scrape(String method, URL url, String... requestHeaders)
+      throws IOException {
+    long timeoutMillis = TimeUnit.SECONDS.toMillis(5);
+    HttpURLConnection con = (HttpURLConnection) url.openConnection();
+    con.setRequestMethod(method);
+    for (int i = 0; i < requestHeaders.length; i += 2) {
+      con.setRequestProperty(requestHeaders[i], requestHeaders[i + 1]);
+    }
+    long start = System.currentTimeMillis();
+    Exception exception = null;
+    while (System.currentTimeMillis() - start < timeoutMillis) {
+      try {
+        if (con.getResponseCode() == 200) {
+          return new Response(
+              con.getResponseCode(),
+              con.getHeaderFields(),
+              IOUtils.toByteArray(con.getInputStream()));
+        } else {
+          return new Response(
+              con.getResponseCode(),
+              con.getHeaderFields(),
+              IOUtils.toByteArray(con.getErrorStream()));
+        }
+      } catch (Exception e) {
+        exception = e;
+        try {
+          Thread.sleep(100);
+        } catch (InterruptedException ignored) {
+          // ignore
+        }
+      }
+    }
+    if (exception != null) {
+      exception.printStackTrace();
+    }
+    fail("timeout while getting metrics from " + url);
+    return null; // will not happen
+  }
+
+  public static class Response {
+    public final int status;
+    private final Map<String, String> headers;
+    public final byte[] body;
+
+    private Response(int status, Map<String, List<String>> headers, byte[] body) {
+      this.status = status;
+      this.headers = new HashMap<>(headers.size());
+      this.body = body;
+      for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
+        if (entry.getKey()
+            != null) { // HttpUrlConnection uses pseudo key "null" for the status line
+          this.headers.put(entry.getKey().toLowerCase(Locale.ROOT), entry.getValue().get(0));
+        }
+      }
+    }
+
+    public String getHeader(String name) {
+      // HTTP headers are case-insensitive
+      return headers.get(name.toLowerCase(Locale.ROOT));
+    }
+
+    public String stringBody() {
+      return new String(body, UTF_8);
+    }
+
+    public String gzipBody() throws IOException {
+      return new String(
+          IOUtils.toByteArray(new GZIPInputStream(new ByteArrayInputStream(body))), UTF_8);
+    }
+
+    public List<Metrics.MetricFamily> protoBody() throws IOException {
+      List<Metrics.MetricFamily> metrics = new ArrayList<>();
+      InputStream in = new ByteArrayInputStream(body);
+      while (in.available() > 0) {
+        metrics.add(Metrics.MetricFamily.parseDelimitedFrom(in));
+      }
+      return metrics;
+    }
+  }
+}

integration-tests/it-exporter/it-exporter-no-protobuf/pom.xml

@@ -0,0 +1,69 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>io.prometheus</groupId>
+        <artifactId>it-exporter</artifactId>
+        <version>1.3.3</version>
+    </parent>
+
+    <artifactId>it-exporter-no-protobuf</artifactId>
+
+    <name>Integration Tests - HTTPServer Exporter Sample - no protobuf</name>
+    <description>
+        HTTPServer Sample for the Exporter Integration Test without protobuf
+    </description>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.prometheus</groupId>
+            <artifactId>prometheus-metrics-exporter-httpserver</artifactId>
+            <version>${project.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>io.prometheus</groupId>
+                    <artifactId>prometheus-metrics-exposition-formats</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>io.prometheus</groupId>
+            <artifactId>prometheus-metrics-core</artifactId>
+            <version>${project.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>io.prometheus</groupId>
+                    <artifactId>prometheus-metrics-exposition-formats</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>exporter-no-protobuf</finalName>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <transformers>
+                                <transformer
+                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>io.prometheus.metrics.it.exporter.httpserver.HTTPServerSample</mainClass>
+                                </transformer>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>