Publish jar for cel extension

.github/workflows/oats-tests.yml

@@ -0,0 +1,38 @@
+name: OATS Tests
+
+on:
+  pull_request:
+    branches:
+      - main
+    paths:
+      - .mise.toml
+      - .github/workflows/oats-tests.yml
+      - cel-sampler/**
+      - .mise/tasks/oats-tests.sh
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  acceptance-tests:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Check out
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - name: Set up JDK for running Gradle
+        uses: actions/setup-java@f2beeb24e141e01a676f977032f5a29d81c9e27e # v5.1.0
+        with:
+          distribution: temurin
+          java-version: 17
+
+      - name: Set up gradle
+        uses: gradle/actions/setup-gradle@4d9f0ba0025fe599b4ebab900eb7f3a1d93ef4c2 # v5.0.0
+        with:
+          cache-read-only: ${{ github.event_name == 'pull_request' }}
+
+      - uses: jdx/mise-action@146a28175021df8ca24f8ee1828cc2a60f980bd5 # v3.5.1
+
+      - name: Run OATS tests
+        run: mise run oats-tests

.mise/tasks/oats-tests.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+#MISE description="Run OATS tests for cel-sampler"
+
+set -euo pipefail
+
+echo "==> Building cel-sampler shadow JAR..."
+./gradlew :cel-sampler:shadowJar
+
+echo "==> Building test application..."
+# testapp is a standalone Gradle project, needs to be built separately
+(cd cel-sampler/testapp && ../../gradlew jar)
+
+echo "==> Running OATS integration tests..."
+(cd cel-sampler && oats -timeout 5m oats/oats.yaml)

cel-sampler/build.gradle.kts

@@ -1,6 +1,7 @@
 plugins {
   id("otel.java-conventions")
   id("otel.publish-conventions")
+  id("com.gradleup.shadow")
 }
 
 description = "Sampler which makes its decision based on semantic attributes values"
@@ -18,3 +19,32 @@ dependencies {
   testImplementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure")
   testImplementation("io.opentelemetry:opentelemetry-sdk-extension-incubator")
 }
+
+tasks {
+  shadowJar {
+    /**
+     * Shaded version of this extension is required when using it as a OpenTelemetry Java Agent
+     * extension. Shading bundles the dependencies required by this extension in the resulting JAR,
+     * ensuring their presence on the classpath at runtime.
+     *
+     * See http://gradleup.com/shadow/introduction/#introduction for reference.
+     */
+    archiveClassifier.set("shadow")
+  }
+
+  jar {
+    /**
+     * We need to publish both - shaded and unshaded variants of the dependency
+     * Shaded dependency is required for use with the Java agent.
+     * Unshaded dependency can be used with OTel Autoconfigure module.
+     *
+     * Not overriding the classifier to empty results in an implicit classifier 'plain' being
+     * used with the standard JAR.
+     */
+    archiveClassifier.set("")
+  }
+
+  assemble {
+    dependsOn(shadowJar)
+  }
+}

cel-sampler/gradle.properties

@@ -0,0 +1,2 @@
+# TODO: uncomment when ready to mark as stable
+# otel.stable=true

cel-sampler/oats/Dockerfile

@@ -0,0 +1,24 @@
+FROM eclipse-temurin:21-jre
+
+WORKDIR /usr/src/app/
+
+# renovate: datasource=github-releases depName=open-telemetry/opentelemetry-java-instrumentation
+ENV OPENTELEMETRY_JAVA_INSTRUMENTATION_VERSION=v2.22.0
+
+COPY ./cel-sampler/testapp/build/libs/testapp.jar ./app.jar
+
+# Add the CEL sampler extension JAR
+COPY ./cel-sampler/build/libs/*-shadow.jar ./extensions/
+
+COPY ./cel-sampler/oats/otel-config.yaml ./otel-config.yaml
+
+ADD --chmod=644 https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/download/$OPENTELEMETRY_JAVA_INSTRUMENTATION_VERSION/opentelemetry-javaagent.jar ./opentelemetry-javaagent.jar
+
+# Configure the Java agent with the CEL sampler extension
+ENV JAVA_TOOL_OPTIONS=-javaagent:./opentelemetry-javaagent.jar
+ENV OTEL_JAVAAGENT_EXTENSIONS=/usr/src/app/extensions/
+
+ENV OTEL_EXPERIMENTAL_CONFIG_FILE=./otel-config.yaml
+
+EXPOSE 8080
+ENTRYPOINT [ "java", "-jar", "./app.jar" ]

cel-sampler/oats/README.md

@@ -0,0 +1,25 @@
+# CEL Sampler OATS Integration Tests
+
+This directory contains acceptance tests for the CEL-based sampler extension using the
+[OATS (OpenTelemetry Acceptance Test Suite)](https://github.com/grafana/oats) framework.
+
+## Overview
+
+These tests verify that the CEL sampler correctly:
+
+- Drops traces for health check endpoints (`/healthcheck`, `/metrics`)
+- Samples traces for regular API endpoints (`/hello`, `/api/data`)
+- Loads correctly as a Java agent extension
+- Works with declarative configuration
+
+## Running the Tests
+
+You can build all assets and run tests using:
+
+`mise run oats-test`
+
+Or manually run just the tests (from the `cel-sampler` directory):
+
+```bash
+~/go/bin/oats oats/oats.yaml
+```

cel-sampler/oats/docker-compose.yml

@@ -0,0 +1,12 @@
+version: '3'
+services:
+  app:
+    build:
+      context: ../../
+      dockerfile: cel-sampler/oats/Dockerfile
+    environment:
+      OTEL_SERVICE_NAME: "cel-sampler-test-app"
+      OTEL_EXPORTER_OTLP_ENDPOINT: http://lgtm:4318
+      OTEL_EXPERIMENTAL_CONFIG_FILE: ./otel-config.yaml
+    ports:
+      - "8080:8080"

cel-sampler/oats/oats.yaml

@@ -0,0 +1,34 @@
+# OATS is an acceptance testing framework for OpenTelemetry - https://github.com/grafana/oats
+oats-schema-version: 2
+
+docker-compose:
+  files:
+    - ./docker-compose.yml
+
+input:
+  - path: /hello
+  - path: /api/data
+  - path: /healthcheck
+  - path: /metrics
+
+expected:
+  traces:
+    # Verify that /hello and /api/data endpoints are sampled
+    - traceql: '{ span.http.route = "/hello" }'
+      equals: "GET /hello"
+      attributes:
+        http.request.method: "GET"
+        http.route: "/hello"
+    - traceql: '{ span.http.route = "/api/data" }'
+      equals: "GET /api/data"
+      attributes:
+        http.request.method: "GET"
+        http.response.status_code: 200
+
+    # Verify that health check and metrics endpoints are dropped:
+    - traceql: '{ span.http.route = "/healthcheck" }'
+      count:
+        max: 0
+    - traceql: '{ span.http.route = "/metrics" }'
+      count:
+        max: 0

cel-sampler/oats/otel-config.yaml

@@ -0,0 +1,27 @@
+# OpenTelemetry Declarative Configuration for CEL-based Sampler Integration Test
+
+file_format: "1.0-rc.2"
+
+resource:
+  attributes:
+    - name: service.name
+      value: cel-sampler-test
+
+tracer_provider:
+  processors:
+    - batch:
+        exporter:
+          otlp_http:
+            endpoint: ${OTEL_EXPORTER_OTLP_ENDPOINT:-http://localhost:4318}/v1/traces
+  sampler:
+    parent_based:
+      root:
+        cel_based:
+          expressions:
+            - expression: 'attribute["url.path"] == "/healthcheck"'
+              action: DROP
+            - expression: 'attribute["url.path"] == "/metrics"'
+              action: DROP
+          # Fallback sampler: sample everything else (including /api/ endpoints)
+          fallback_sampler:
+            always_on: {}

cel-sampler/testapp/.gitignore

@@ -0,0 +1,2 @@
+build/
+.gradle/

cel-sampler/testapp/build.gradle.kts

@@ -0,0 +1,16 @@
+plugins {
+  java
+  application
+}
+
+application {
+  mainClass.set("io.opentelemetry.contrib.sampler.cel.testapp.SimpleServer")
+}
+
+tasks.jar {
+  manifest {
+    attributes["Main-Class"] = "io.opentelemetry.contrib.sampler.cel.testapp.SimpleServer"
+  }
+  duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+  from(configurations.runtimeClasspath.get().map { if (it.isDirectory) it else zipTree(it) })
+}

cel-sampler/testapp/settings.gradle.kts

@@ -0,0 +1 @@
+rootProject.name = "testapp"

cel-sampler/testapp/src/main/java/io/opentelemetry/contrib/sampler/cel/testapp/SimpleServer.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.contrib.sampler.cel.testapp;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.InetSocketAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.logging.Logger;
+
+/**
+ * Simple HTTP server for testing CEL-based sampler extension.
+ *
+ * <p>This application provides multiple endpoints to test different sampling behaviors:
+ * - /api/data - Should be sampled (API endpoint)
+ * - /healthcheck - Should be dropped (health check endpoint)
+ * - /metrics - Should be dropped (metrics endpoint)
+ * - /hello - Should be sampled (regular endpoint)
+ */
+public class SimpleServer {
+
+  private static final Logger logger = Logger.getLogger(SimpleServer.class.getName());
+
+  public static void main(String[] args) throws Exception {
+    int port = 8080;
+    HttpServer server = HttpServer.create(new InetSocketAddress(port), 0);
+
+    // Regular endpoints that should be sampled
+    server.createContext("/hello", new ResponseHandler("Hello from test app!"));
+    server.createContext("/api/data", new ResponseHandler("API data response"));
+
+    // Health/monitoring endpoints that should be dropped
+    server.createContext("/healthcheck", new ResponseHandler("OK"));
+    server.createContext("/metrics", new ResponseHandler("metrics=1"));
+
+    server.setExecutor(null);
+
+    logger.info("Starting server on port " + port);
+    server.start();
+  }
+
+  static class ResponseHandler implements HttpHandler {
+    private final String response;
+
+    ResponseHandler(String response) {
+      this.response = response;
+    }
+
+    @Override
+    public void handle(HttpExchange exchange) throws IOException {
+      byte[] responseBytes = response.getBytes(StandardCharsets.UTF_8);
+
+      exchange.sendResponseHeaders(200, responseBytes.length);
+      try (OutputStream os = exchange.getResponseBody()) {
+        os.write(responseBytes);
+      }
+
+      logger.info("Handled request to " + exchange.getRequestURI().getPath());
+    }
+  }
+}

mise.toml

@@ -1,6 +1,7 @@
 [tools]
 lychee = "0.22.0"
 markdownlint-cli2 = "0.20.0"
+"go:github.com/grafana/oats" = "0.6.0"
 
 [settings]
 # Only install tools explicitly defined in the [tools] section above
@@ -10,4 +11,5 @@ idiomatic_version_file_enable_tools = []
 # Based on: https://github.com/jdx/mise/discussions/4461
 windows_executable_extensions = ["sh"]
 windows_default_file_shell_args = "bash"
+unix_default_file_shell_args = "bash"
 use_file_shell_for_executable_tasks = true