Add Fahrschein User-Agent to Nakadi requests (#350)

* Add User-Agent to Nakadi requests We would like to have an easy way to get some statistics around Fahrschein usage in general, and which versions, which JDK version, and via which HTTP client implementation specificially, in order to a) justify the time we're spending on the library, b) get more insights about builder behaviour. The header should be set by default (not overridable initially). Format "Fahrschein/" [FahrscheinVersion] " (" [HttpClient] "; " [Java Version] ("; " [Additional Property])* ")" Examples User-Agent: Fahrschein/0.22.0 (Simple; Java11) User-Agent: Fahrschein/0.22.0 (ApacheHttpClient; Java8) User-Agent: Fahrschein/0.22.0 (JavaNet; Java17; experimental-features=a,b,c) User-Agent: Fahrschein/0.22.0 (Spring; Java8; Kotlin) * Fix github workflow references in README * Update fahrschein-http-api/src/main/java/org/zalando/fahrschein/http/api/UserAgent.java Co-authored-by: Malte <[email protected]> * Update fahrschein-http-api/src/main/java/org/zalando/fahrschein/http/api/UserAgent.java Co-authored-by: Malte <[email protected]> * Update fahrschein-http-api/src/main/java/org/zalando/fahrschein/http/api/UserAgent.java Co-authored-by: Malte <[email protected]> * Update fahrschein-http-api/src/main/java/org/zalando/fahrschein/http/api/UserAgent.java Co-authored-by: Malte <[email protected]> * Reduce logging from error to warn * mark project.version as task input Co-authored-by: Malte <[email protected]>
zalando-nakadi · Jul 21, 2022 · b8b2828 · b8b2828
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diff --git a/README.md b/README.md
@@ -326,7 +326,7 @@ Most dependencies are defined on a per-subproject level, only the versions for t
 ./gradlew test -Pjackson.version=2.9.0
 ```
 
-The [integration tests](.github/workflows/ci.yaml) include running the build with our supported baseline dependency as well as the latest micro release of Jackson, Apache HttpClient and Spring. Please update the section in the README when bumping dependency baselines, and add this to the release notes.
+The [integration tests](.github/workflows/ci.yml) include running the build with our supported baseline dependency as well as the latest micro release of Jackson, Apache HttpClient and Spring. Please update the section in the README when bumping dependency baselines, and add this to the release notes.
 
 ### End-to-End tests
 
@@ -353,7 +353,7 @@ open build/reports/dependency-check-report.html
 
 ### Releasing
 
-Fahrschein uses Github Workflows to [build](.github/workflows/ci.yaml) and [publish releases](.github/workflows/maven-publish.yaml). This happens automatically whenever a new release is created in Github. After creating a release, please bump the `project.version` property in [gradle.properties](./gradle.properties).
+Fahrschein uses Github Workflows to [build](.github/workflows/ci.yml) and [publish releases](.github/workflows/maven-publish.yml). This happens automatically whenever a new release is created in Github. After creating a release, please bump the `project.version` property in [gradle.properties](./gradle.properties).
 
 If needed, you can preview the signed release artifacts in your local maven repository.
 

diff --git a/fahrschein-http-api/src/main/java/org/zalando/fahrschein/http/api/Headers.java b/fahrschein-http-api/src/main/java/org/zalando/fahrschein/http/api/Headers.java
@@ -11,6 +11,7 @@ public interface Headers {
     String CONTENT_TYPE = "Content-Type";
     String CONTENT_ENCODING = "Content-Encoding";
     String ACCEPT_ENCODING = "Accept-Encoding";
+    String USER_AGENT = "User-Agent";
 
     List<String> get(String headerName);
 

diff --git a/fahrschein-http-api/src/main/java/org/zalando/fahrschein/http/api/UserAgent.java b/fahrschein-http-api/src/main/java/org/zalando/fahrschein/http/api/UserAgent.java
@@ -0,0 +1,57 @@
+package org.zalando.fahrschein.http.api;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Properties;
+
+public final class UserAgent {
+    private static final String PROPERTIES_FILE = "fahrschein.properties";
+    private static final Logger logger = LoggerFactory.getLogger(UserAgent.class);
+
+    private static final Properties fahrscheinProperties = new Properties();
+
+    static {
+        try (final InputStream stream =
+                     UserAgent.class.getResourceAsStream("/" + PROPERTIES_FILE)) {
+            if (stream != null) {
+                fahrscheinProperties.load(stream);
+            } else {
+                logger.warn("Properties file not found: {}", PROPERTIES_FILE);
+            }
+        } catch (IOException e) {
+            logger.warn("Cannot read file: " + PROPERTIES_FILE, e);
+        }
+    }
+
+    private static final String AGENT_STR_TEMPLATE = "Fahrschein/%s (%s; Java%d)";
+
+    private final String userAgent;
+
+    public UserAgent(Class implementation) {
+        this.userAgent = String.format(AGENT_STR_TEMPLATE, fahrscheinVersion(), implementation.getSimpleName().replace("RequestFactory", ""), javaVersion());
+    }
+
+    public String userAgent() {
+        return userAgent;
+    }
+
+    static String fahrscheinVersion() {
+        return String.valueOf(fahrscheinProperties.get("fahrschein-version"));
+    }
+
+    static int javaVersion() {
+        String version = System.getProperty("java.version");
+        if (version.startsWith("1.")) {
+            version = version.substring(2, 3);
+        } else {
+            int dot = version.indexOf(".");
+            if (dot != -1) {
+                version = version.substring(0, dot);
+            }
+        }
+        return Integer.parseInt(version);
+    }
+}
diff --git a/fahrschein-http-api/src/test/java/org/zalando/fahrschein/http/api/UserAgentTest.java b/fahrschein-http-api/src/test/java/org/zalando/fahrschein/http/api/UserAgentTest.java
@@ -0,0 +1,30 @@
+package org.zalando.fahrschein.http.api;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class UserAgentTest {
+
+    abstract class DummyRequestFactory implements RequestFactory {}
+
+    @Test
+    public void javaVersion() {
+        String version = System.getProperty("java.version");
+        int javaVersion = UserAgent.javaVersion();
+        if (version.startsWith("1.8")) {
+            assertEquals(8, javaVersion, "Java 8");
+        } else {
+            assertTrue(version.startsWith(String.valueOf(javaVersion)));
+            assertTrue(javaVersion > 8, "Java " + javaVersion);
+        }
+    }
+
+    @Test
+    public void userAgentString() {
+        UserAgent ua = new UserAgent(DummyRequestFactory.class);
+        String userAgent = ua.userAgent();
+        assertEquals("Fahrschein/0.1.0-SNAPSHOT (Dummy; Java" + UserAgent.javaVersion() + ")", userAgent);
+    }
+
+}
diff --git a/fahrschein-http-api/src/test/resources/fahrschein.properties b/fahrschein-http-api/src/test/resources/fahrschein.properties
@@ -0,0 +1,2 @@
+# for testing
+fahrschein-version=0.1.0-SNAPSHOT
diff --git a/...n-http-jdk11/src/main/java/org/zalando/fahrschein/http/jdk11/JavaNetBufferingRequest.java b/...n-http-jdk11/src/main/java/org/zalando/fahrschein/http/jdk11/JavaNetBufferingRequest.java
@@ -68,7 +68,7 @@ public void add(String headerName, String value) {
 
             @Override
             public void put(String headerName, String value) {
-                request.header(headerName, value);
+                request.setHeader(headerName, value);
             }
 
             @Override

diff --git a/...rt/src/testFixtures/java/org/zalando/fahrschein/http/test/AbstractRequestFactoryTest.java b/...rt/src/testFixtures/java/org/zalando/fahrschein/http/test/AbstractRequestFactoryTest.java
@@ -55,6 +55,26 @@ public static void startServer() throws IOException {
     @Captor
     public ArgumentCaptor<HttpExchange> exchangeCaptor;
 
+    @Test
+    public void testUserAgent() throws IOException {
+        // given
+        String expectedResponse = "{}";
+        HttpHandler spy = Mockito.spy(new SimpleRequestResponseContentHandler(expectedResponse));
+        server.createContext("/user-agent", spy);
+
+        // when
+        final RequestFactory f = defaultRequestFactory(ContentEncoding.IDENTITY);
+        Request r = f.createRequest(serverAddress.resolve("/user-agent"), "GET");
+        r.getHeaders().put("User-Agent", "Test");
+        Response executed = r.execute();
+        readStream(executed.getBody());
+
+        // then
+        Mockito.verify(spy).handle(exchangeCaptor.capture());
+        HttpExchange capturedArgument = exchangeCaptor.getValue();
+        assertThat("UserAgent header", capturedArgument.getRequestHeaders().get("user-agent"), equalTo(Arrays.asList("Test")));
+    }
+
     @Test
     public void testGzippedResponseBody() throws IOException {
         // given

diff --git a/fahrschein/build.gradle b/fahrschein/build.gradle
@@ -19,3 +19,37 @@ dependencies {
 }
 
 publishing.publications.maven.pom.description = 'A Java client for the Nakadi event bus'
+
+def generateResourcesTask = tasks.register("generate-resources", GenerateResourcesTask) {
+    resourcesDir.set(layout.buildDirectory.dir("generated-resources/main"))
+}
+
+sourceSets {
+    main {
+        output.dir(generateResourcesTask)
+    }
+}
+
+idea {
+    module {
+        // Marks the already(!) added srcDir as "generated"
+        generatedSourceDirs += file('build/generated-resources/main')
+    }
+}
+
+abstract class GenerateResourcesTask extends DefaultTask {
+
+    @Input
+    String getVersion() {
+        return project.version
+    }
+
+    @OutputDirectory
+    abstract DirectoryProperty getResourcesDir()
+
+    @TaskAction
+    def generateResources() {
+        def generated = resourcesDir.file("fahrschein.properties").get().asFile
+        generated.text = "fahrschein-version=" + getVersion()
+    }
+}
diff --git a/fahrschein/src/main/java/org/zalando/fahrschein/NakadiClientBuilder.java b/fahrschein/src/main/java/org/zalando/fahrschein/NakadiClientBuilder.java
@@ -2,6 +2,7 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.zalando.fahrschein.http.api.RequestFactory;
+
 import javax.annotation.Nullable;
 import java.net.URI;
 
@@ -48,7 +49,7 @@ public NakadiClientBuilder withCursorManager(CursorManager cursorManager) {
     }
 
     static RequestFactory wrapClientHttpRequestFactory(RequestFactory delegate, @Nullable AuthorizationProvider authorizationProvider) {
-        RequestFactory requestFactory = new ProblemHandlingRequestFactory(delegate);
+        RequestFactory requestFactory = new ProblemHandlingRequestFactory(new UserAgentRequestFactory(delegate));
         if (authorizationProvider != null) {
             requestFactory = new AuthorizedRequestFactory(requestFactory, authorizationProvider);
         }

diff --git a/fahrschein/src/main/java/org/zalando/fahrschein/UserAgentRequestFactory.java b/fahrschein/src/main/java/org/zalando/fahrschein/UserAgentRequestFactory.java
@@ -0,0 +1,26 @@
+package org.zalando.fahrschein;
+
+import org.zalando.fahrschein.http.api.Headers;
+import org.zalando.fahrschein.http.api.Request;
+import org.zalando.fahrschein.http.api.RequestFactory;
+import org.zalando.fahrschein.http.api.UserAgent;
+
+import java.io.IOException;
+import java.net.URI;
+
+public class UserAgentRequestFactory implements RequestFactory {
+    private final RequestFactory delegate;
+    private final String userAgent;
+
+    UserAgentRequestFactory(final RequestFactory delegate) {
+        this.userAgent = new UserAgent(delegate.getClass()).userAgent();
+        this.delegate = delegate;
+    }
+
+    @Override
+    public Request createRequest(URI uri, String method) throws IOException {
+        final Request request = delegate.createRequest(uri, method);
+        request.getHeaders().put(Headers.USER_AGENT, userAgent);
+        return request;
+    }
+}
diff --git a/fahrschein/src/test/java/org/zalando/fahrschein/NakadiClientTest.java b/fahrschein/src/test/java/org/zalando/fahrschein/NakadiClientTest.java
@@ -1,5 +1,6 @@
 package org.zalando.fahrschein;
 
+import org.hamcrest.Matchers;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.zalando.fahrschein.domain.Partition;
@@ -56,6 +57,17 @@ public void setup() {
         this.client = nakadiClient;
     }
 
+    @Test
+    public void shouldAddUserAgent() throws IOException {
+        server.expectRequestTo("http://example.com/event-types/foobar/partitions", "GET")
+                .andExpectHeader("User-Agent", Matchers.startsWith("Fahrschein/"))
+                .andRespondWith(200, ContentType.APPLICATION_JSON, "[]")
+                .setup();
+
+        client.getPartitions("foobar");
+        server.verify();
+    }
+
     @Test
     public void shouldGetPartitions() throws IOException {
         server.expectRequestTo("http://example.com/event-types/foobar/partitions", "GET")

diff --git a/fahrschein/src/test/java/org/zalando/fahrschein/UserAgentRequestFactoryTest.java b/fahrschein/src/test/java/org/zalando/fahrschein/UserAgentRequestFactoryTest.java
@@ -0,0 +1,59 @@
+package org.zalando.fahrschein;
+
+import org.junit.jupiter.api.Test;
+import org.zalando.fahrschein.http.api.Headers;
+import org.zalando.fahrschein.http.api.HeadersImpl;
+import org.zalando.fahrschein.http.api.Request;
+import org.zalando.fahrschein.http.api.RequestFactory;
+import org.zalando.fahrschein.http.api.Response;
+import org.zalando.fahrschein.http.api.UserAgent;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URI;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class UserAgentRequestFactoryTest {
+    static class DummyRequestFactory implements RequestFactory {
+
+        @Override
+        public Request createRequest(URI uri, String method) throws IOException {
+            return new Request() {
+                private final Headers headers = new HeadersImpl();
+                @Override
+                public String getMethod() {
+                    return method;
+                }
+
+                @Override
+                public URI getURI() {
+                    return uri;
+                }
+
+                @Override
+                public Headers getHeaders() {
+                    return headers;
+                }
+
+                @Override
+                public OutputStream getBody() throws IOException {
+                    return null;
+                }
+
+                @Override
+                public Response execute() throws IOException {
+                    return null;
+                }
+            };
+        }
+    }
+
+    @Test
+    public void appendUserAgentToRequest() throws IOException {
+        UserAgent ua = new UserAgent(DummyRequestFactory.class);
+        UserAgentRequestFactory rf = new UserAgentRequestFactory(new DummyRequestFactory());
+        Request r = rf.createRequest(URI.create("dummy://req"), "POST");
+        assertEquals(ua.userAgent(), r.getHeaders().getFirst("User-Agent"));
+    }
+}
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		# for testing
		fahrschein-version=0.1.0-SNAPSHOT