Introduce HttpJakartaServletRequestTags

Prior to this commit, `HttpRequestTags` would provide Tags for both
"javax.*" and "jakarta.*" variants of `HttpServletRequest`. While the
`HttpServletRequestTagsProvider` and
`HttpJakartaServletRequestTagsProvider` are separate interfaces, they
both use `HttpRequestTags` and import all types exposed on its methods.

It is strongly advised not to import both "javax.*" and "jakarta.*"
variants in a typical application and the current arrangement prevents
this best practice.

This commit deprecates Jakarta methods variants in `HttpRequestTags` and
moves them to `HttpJakartaServletRequestTags`. This allows a clean
dependency setup for Jakarta apps and a migration path for all in the
meantime.

Closes gh-3804

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/http/DefaultHttpJakartaServletRequestTagsProvider.java

@@ -32,8 +32,8 @@ public class DefaultHttpJakartaServletRequestTagsProvider implements HttpJakarta
 
     @Override
     public Iterable<Tag> getTags(HttpServletRequest request, HttpServletResponse response) {
-        return Tags.of(HttpRequestTags.method(request), HttpRequestTags.status(response),
-                HttpRequestTags.outcome(response));
+        return Tags.of(HttpJakartaServletRequestTags.method(request), HttpJakartaServletRequestTags.status(response),
+                HttpJakartaServletRequestTags.outcome(response));
     }
 
 }

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/http/HttpJakartaServletRequestTags.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2023 VMware, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micrometer.core.instrument.binder.http;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+import io.micrometer.common.lang.Nullable;
+import io.micrometer.common.util.StringUtils;
+import io.micrometer.core.annotation.Incubating;
+import io.micrometer.core.instrument.Tag;
+
+/**
+ * Tags for {@link jakarta.servlet.http.HttpServletRequest HTTP Jakarta requests}.
+ *
+ * @author Jon Schneider
+ * @author Brian Clozel
+ * @since 1.12.0
+ */
+@Incubating(since = "1.12.0")
+public class HttpJakartaServletRequestTags {
+
+    private static final Tag EXCEPTION_NONE = Tag.of("exception", "None");
+
+    private static final Tag STATUS_UNKNOWN = Tag.of("status", "UNKNOWN");
+
+    private static final Tag METHOD_UNKNOWN = Tag.of("method", "UNKNOWN");
+
+    private HttpJakartaServletRequestTags() {
+    }
+
+    /**
+     * Creates a {@code method} tag based on the {@link HttpServletRequest#getMethod()
+     * method} of the given {@code request}.
+     * @param request the request
+     * @return the method tag whose value is a capitalized method (e.g. GET).
+     */
+    public static Tag method(@Nullable HttpServletRequest request) {
+        return (request != null) ? Tag.of("method", request.getMethod()) : METHOD_UNKNOWN;
+    }
+
+    /**
+     * Creates a {@code status} tag based on the status of the given {@code response}.
+     * @param response the HTTP response
+     * @return the status tag derived from the status of the response
+     */
+    public static Tag status(@Nullable HttpServletResponse response) {
+        return (response != null) ? Tag.of("status", Integer.toString(response.getStatus())) : STATUS_UNKNOWN;
+    }
+
+    /**
+     * Creates an {@code exception} tag based on the {@link Class#getSimpleName() simple
+     * name} of the class of the given {@code exception}.
+     * @param exception the exception, may be {@code null}
+     * @return the exception tag derived from the exception
+     */
+    public static Tag exception(@Nullable Throwable exception) {
+        if (exception != null) {
+            String simpleName = exception.getClass().getSimpleName();
+            return Tag.of("exception",
+                    StringUtils.isNotBlank(simpleName) ? simpleName : exception.getClass().getName());
+        }
+        return EXCEPTION_NONE;
+    }
+
+    /**
+     * Creates an {@code outcome} tag based on the status of the given {@code response}.
+     * @param response the HTTP response
+     * @return the outcome tag derived from the status of the response
+     */
+    public static Tag outcome(@Nullable HttpServletResponse response) {
+        Outcome outcome = (response != null) ? Outcome.forStatus(response.getStatus()) : Outcome.UNKNOWN;
+        return outcome.asTag();
+    }
+
+}

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/http/HttpRequestTags.java

@@ -57,9 +57,12 @@ public static Tag method(HttpServletRequest request) {
      * @param request the request
      * @return the method tag whose value is a capitalized method (e.g. GET).
      * @since 1.10.0
+     * @deprecated since 1.12.0 in favor of
+     * {@link HttpJakartaServletRequestTags#method(jakarta.servlet.http.HttpServletRequest)}
      */
+    @Deprecated
     public static Tag method(jakarta.servlet.http.HttpServletRequest request) {
-        return (request != null) ? Tag.of("method", request.getMethod()) : METHOD_UNKNOWN;
+        return HttpJakartaServletRequestTags.method(request);
     }
 
     /**
@@ -76,9 +79,12 @@ public static Tag status(HttpServletResponse response) {
      * @param response the HTTP response
      * @return the status tag derived from the status of the response
      * @since 1.10.0
+     * @deprecated since 1.12.0 in favor of
+     * {@link HttpJakartaServletRequestTags#status(jakarta.servlet.http.HttpServletResponse)}
      */
+    @Deprecated
     public static Tag status(jakarta.servlet.http.HttpServletResponse response) {
-        return (response != null) ? Tag.of("status", Integer.toString(response.getStatus())) : STATUS_UNKNOWN;
+        return HttpJakartaServletRequestTags.status(response);
     }
 
     /**
@@ -111,10 +117,12 @@ public static Tag outcome(HttpServletResponse response) {
      * @param response the HTTP response
      * @return the outcome tag derived from the status of the response
      * @since 1.10.0
+     * @deprecated since 1.12.0 in favor of
+     * {@link HttpJakartaServletRequestTags#outcome(jakarta.servlet.http.HttpServletResponse)}
      */
+    @Deprecated
     public static Tag outcome(jakarta.servlet.http.HttpServletResponse response) {
-        Outcome outcome = (response != null) ? Outcome.forStatus(response.getStatus()) : Outcome.UNKNOWN;
-        return outcome.asTag();
+        return HttpJakartaServletRequestTags.outcome(response);
     }
 
 }

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/http/HttpJakartaServletRequestTagsTest.java

@@ -0,0 +1,144 @@
+/*
+ * Copyright 2023 VMware, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micrometer.core.instrument.binder.http;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import io.micrometer.core.instrument.Tag;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Tests for {@link HttpJakartaServletRequestTags} and {@link HttpRequestTags}.
+ *
+ * @author Brian Clozel
+ */
+class HttpJakartaServletRequestTagsTest {
+
+    @Test
+    void nullRequestShouldContributeUnknownMethodTag() {
+        Tag unknownMethod = Tag.of("method", "UNKNOWN");
+        HttpServletRequest jakartaRequest = null;
+        Tag result = HttpJakartaServletRequestTags.method(jakartaRequest);
+        assertThat(result).isEqualTo(unknownMethod);
+
+        javax.servlet.http.HttpServletRequest javaxRequest = null;
+        result = HttpRequestTags.method(javaxRequest);
+        assertThat(result).isEqualTo(unknownMethod);
+    }
+
+    @Test
+    void requestShouldContributeMethodTag() {
+        Tag httpGet = Tag.of("method", "GET");
+        HttpServletRequest jakartaRequest = mockJakartaRequest("GET");
+        Tag result = HttpJakartaServletRequestTags.method(jakartaRequest);
+        assertThat(result).isEqualTo(httpGet);
+
+        javax.servlet.http.HttpServletRequest javaxRequest = mockJavaxRequest("GET");
+        result = HttpRequestTags.method(javaxRequest);
+        assertThat(result).isEqualTo(httpGet);
+    }
+
+    @Test
+    void nullResponseShouldContributeUnknownStatusTag() {
+        Tag unknownStatus = Tag.of("status", "UNKNOWN");
+        HttpServletResponse jakartaResponse = null;
+        Tag result = HttpJakartaServletRequestTags.status(jakartaResponse);
+        assertThat(result).isEqualTo(unknownStatus);
+
+        javax.servlet.http.HttpServletResponse javaxResponse = null;
+        result = HttpRequestTags.status(javaxResponse);
+        assertThat(result).isEqualTo(unknownStatus);
+    }
+
+    @Test
+    void responseShouldContributeStatusTag() {
+        Tag httpOk = Tag.of("status", "200");
+        HttpServletResponse jakartaResponse = mockJakartaResponse(200);
+        Tag result = HttpJakartaServletRequestTags.status(jakartaResponse);
+        assertThat(result).isEqualTo(httpOk);
+
+        javax.servlet.http.HttpServletResponse javaxResponse = mockJavaxResponse(200);
+        result = HttpRequestTags.status(javaxResponse);
+        assertThat(result).isEqualTo(httpOk);
+    }
+
+    @Test
+    void nullExceptionShouldContributeNoneExceptionTag() {
+        Tag exceptionNone = Tag.of("exception", "None");
+        Tag result = HttpJakartaServletRequestTags.exception(null);
+        assertThat(result).isEqualTo(exceptionNone);
+    }
+
+    @Test
+    void exceptionShouldContributeExceptionTag() {
+        Tag illegalStateTag = Tag.of("exception", "IllegalStateException");
+        Tag result = HttpJakartaServletRequestTags.exception(new IllegalStateException());
+        assertThat(result).isEqualTo(illegalStateTag);
+    }
+
+    @Test
+    void nullResponseShouldContributeUnknownOutcomeTag() {
+        Tag unknownOutcome = Tag.of("outcome", "UNKNOWN");
+        HttpServletResponse jakartaResponse = null;
+        Tag result = HttpJakartaServletRequestTags.outcome(jakartaResponse);
+        assertThat(result).isEqualTo(unknownOutcome);
+
+        javax.servlet.http.HttpServletResponse javaxResponse = null;
+        result = HttpRequestTags.outcome(javaxResponse);
+        assertThat(result).isEqualTo(unknownOutcome);
+    }
+
+    @Test
+    void responseShouldContributeOutcomeTag() {
+        Tag unknownOutcome = Tag.of("outcome", "SUCCESS");
+        HttpServletResponse jakartaResponse = mockJakartaResponse(200);
+        Tag result = HttpJakartaServletRequestTags.outcome(jakartaResponse);
+        assertThat(result).isEqualTo(unknownOutcome);
+
+        javax.servlet.http.HttpServletResponse javaxResponse = mockJavaxResponse(200);
+        result = HttpRequestTags.outcome(javaxResponse);
+        assertThat(result).isEqualTo(unknownOutcome);
+    }
+
+    private HttpServletRequest mockJakartaRequest(String method) {
+        HttpServletRequest jakartaRequest = mock(HttpServletRequest.class);
+        when(jakartaRequest.getMethod()).thenReturn(method);
+        return jakartaRequest;
+    }
+
+    private javax.servlet.http.HttpServletRequest mockJavaxRequest(String method) {
+        javax.servlet.http.HttpServletRequest javaxRequest = mock(javax.servlet.http.HttpServletRequest.class);
+        when(javaxRequest.getMethod()).thenReturn(method);
+        return javaxRequest;
+    }
+
+    private HttpServletResponse mockJakartaResponse(int status) {
+        HttpServletResponse jakartaResponse = mock(HttpServletResponse.class);
+        when(jakartaResponse.getStatus()).thenReturn(status);
+        return jakartaResponse;
+    }
+
+    private javax.servlet.http.HttpServletResponse mockJavaxResponse(int status) {
+        javax.servlet.http.HttpServletResponse javaxResponse = mock(javax.servlet.http.HttpServletResponse.class);
+        when(javaxResponse.getStatus()).thenReturn(status);
+        return javaxResponse;
+    }
+
+}