Remove prometheus-metrics-shaded-protobuf dependency from the agent

Author: laurit

javaagent-tooling/build.gradle.kts

@@ -34,7 +34,10 @@ dependencies {
   implementation("io.opentelemetry:opentelemetry-exporter-otlp")
   implementation("io.opentelemetry:opentelemetry-exporter-logging-otlp")
 
-  implementation("io.opentelemetry:opentelemetry-exporter-prometheus")
+  implementation("io.opentelemetry:opentelemetry-exporter-prometheus") {
+    exclude(group = "io.prometheus", module = "prometheus-metrics-shaded-protobuf")
+  }
+  compileOnly("io.prometheus:prometheus-metrics-exposition-formats:1.3.1")
   implementation("io.opentelemetry:opentelemetry-exporter-zipkin")
 
   implementation("io.opentelemetry:opentelemetry-sdk-extension-jaeger-remote-sampler")

javaagent-tooling/src/main/java/io/prometheus/metrics/expositionformats/PrometheusProtobufWriter.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.prometheus.metrics.expositionformats;
+
+import io.prometheus.metrics.model.snapshots.MetricSnapshots;
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * Replacement for prometheus protobuf writer that does not depend on any of the protobuf classes.
+ * This allows us to exclude io.prometheus:prometheus-metrics-shaded-protobuf dependency.
+ *
+ * @see <a href="https://github.com/prometheus/client_java/blob/main/prometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusProtobufWriter.java">PrometheusProtobufWriter</a>
+ */
+public class PrometheusProtobufWriter implements ExpositionFormatWriter {
+
+  @Override
+  public boolean accepts(String acceptHeader) {
+    return false;
+  }
+
+  @Override
+  public void write(OutputStream out, MetricSnapshots metricSnapshots) throws IOException {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getContentType() {
+    throw new UnsupportedOperationException();
+  }
+}