Config viewer as part of vertx-http in dev mode

bom/runtime/pom.xml

@@ -2242,6 +2242,11 @@
                 <artifactId>smallrye-mutiny-vertx-web-client</artifactId>
                 <version>${mutiny-client.version}</version>
             </dependency>
+            <dependency>
+                <groupId>io.vertx</groupId>
+                <artifactId>vertx-core</artifactId>
+                <version>${vertx.version}</version>
+            </dependency>
             <dependency>
                 <groupId>io.vertx</groupId>
                 <artifactId>vertx-web</artifactId>

extensions/vertx-http/deployment/src/main/java/io/quarkus/vertx/http/deployment/VertxHttpProcessor.java

@@ -6,11 +6,15 @@
 import java.util.Optional;
 import java.util.stream.Collectors;
 
+import javax.inject.Singleton;
+
 import org.eclipse.microprofile.config.ConfigProvider;
+import org.jboss.jandex.DotName;
 
 import io.quarkus.arc.deployment.AdditionalBeanBuildItem;
 import io.quarkus.arc.deployment.BeanContainerBuildItem;
 import io.quarkus.builder.BuildException;
+import io.quarkus.deployment.IsDevelopment;
 import io.quarkus.deployment.IsNormal;
 import io.quarkus.deployment.annotations.BuildProducer;
 import io.quarkus.deployment.annotations.BuildStep;
@@ -30,11 +34,14 @@
 import io.quarkus.vertx.core.deployment.EventLoopCountBuildItem;
 import io.quarkus.vertx.core.deployment.InternalWebVertxBuildItem;
 import io.quarkus.vertx.http.runtime.CurrentVertxRequest;
+import io.quarkus.vertx.http.runtime.HandlerType;
 import io.quarkus.vertx.http.runtime.HttpBuildTimeConfig;
 import io.quarkus.vertx.http.runtime.HttpConfiguration;
 import io.quarkus.vertx.http.runtime.RouterProducer;
 import io.quarkus.vertx.http.runtime.VertxHttpRecorder;
 import io.quarkus.vertx.http.runtime.cors.CORSRecorder;
+import io.quarkus.vertx.http.runtime.devmode.ConfigHolder;
+import io.quarkus.vertx.http.runtime.devmode.ConfigViewerHandler;
 import io.quarkus.vertx.http.runtime.filters.Filter;
 import io.vertx.core.Handler;
 import io.vertx.core.impl.VertxImpl;
@@ -166,4 +173,17 @@ ServiceStartBuildItem finalizeRouter(
     RuntimeInitializedClassBuildItem configureNativeCompilation() {
         return new RuntimeInitializedClassBuildItem("io.vertx.ext.web.handler.sockjs.impl.XhrTransport");
     }
+
+    @BuildStep(onlyIf = IsDevelopment.class)
+    public void configViewerRoute(HttpBuildTimeConfig httpBuildTimeConfig,
+            BuildProducer<AdditionalBeanBuildItem> beans,
+            BuildProducer<RouteBuildItem> routes) {
+        beans.produce(AdditionalBeanBuildItem.builder()
+                .addBeanClass(ConfigHolder.class)
+                .setDefaultScope(DotName.createSimple(Singleton.class.getName()))
+                .setUnremovable()
+                .build());
+        routes.produce(new RouteBuildItem(httpBuildTimeConfig.configPath,
+                new ConfigViewerHandler(), HandlerType.BLOCKING));
+    }
 }

extensions/vertx-http/deployment/src/test/java/io/quarkus/vertx/http/configviewer/ShowConfigTest.java

@@ -0,0 +1,29 @@
+package io.quarkus.vertx.http.configviewer;
+
+import static io.restassured.RestAssured.when;
+import static org.hamcrest.Matchers.hasItem;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusDevModeTest;
+import io.restassured.http.ContentType;
+
+public class ShowConfigTest {
+
+    @RegisterExtension
+    static final QuarkusDevModeTest test = new QuarkusDevModeTest()
+            .setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class)
+                    .addAsResource(new StringAsset("foo=bar"), "application.properties"));
+
+    @Test
+    void testConfig() {
+        when().get("/config").then()
+                .statusCode(200)
+                .contentType(ContentType.JSON)
+                .body("sources.properties.foo", hasItem("bar"));
+    }
+}

extensions/vertx-http/runtime/pom.xml

@@ -50,6 +50,10 @@
                 </exclusion>
             </exclusions>
         </dependency>
+        <dependency>
+            <groupId>io.vertx</groupId>
+            <artifactId>vertx-core</artifactId>
+        </dependency>
     </dependencies>
 
     <build>

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/HttpBuildTimeConfig.java

@@ -21,4 +21,10 @@ public class HttpBuildTimeConfig {
      */
     @ConfigItem
     public boolean virtual;
+
+    /**
+     * The path for the config viewer.
+     */
+    @ConfigItem(defaultValue = "/config")
+    public String configPath;
 }

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/devmode/ConfigHolder.java

@@ -0,0 +1,11 @@
+package io.quarkus.vertx.http.runtime.devmode;
+
+import javax.inject.Inject;
+
+import org.eclipse.microprofile.config.Config;
+
+public class ConfigHolder {
+
+    @Inject
+    Config config;
+}

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/devmode/ConfigViewer.java

@@ -0,0 +1,77 @@
+package io.quarkus.vertx.http.runtime.devmode;
+
+import java.util.Set;
+import java.util.SortedSet;
+import java.util.TreeSet;
+
+import org.eclipse.microprofile.config.Config;
+import org.eclipse.microprofile.config.spi.ConfigSource;
+import org.jboss.logging.Logger;
+
+import io.vertx.core.json.JsonArray;
+import io.vertx.core.json.JsonObject;
+
+/**
+ * Turns a {@link Config} into a JSON object with all config sources and properties as JSON. The config sources are
+ * sorted descending by ordinal, the properties by name. If no config is defined an empty JSON object is returned.
+ *
+ * <p>
+ * A typical output might look like:
+ * </p>
+ *
+ * <pre>
+ * {
+ *   "sources": [
+ *     {
+ *       "source": "source0",
+ *       "ordinal": 200,
+ *       "properties": {
+ *         "key": "value"
+ *       }
+ *     },
+ *     {
+ *       "source": "source1",
+ *       "ordinal": 100,
+ *       "properties": {
+ *         "key": "value"
+ *       }
+ *     }
+ *   ]
+ * }
+ * </pre>
+ */
+class ConfigViewer {
+
+    private static final Logger LOGGER = Logger.getLogger(ConfigViewer.class.getName());
+
+    JsonObject dump(Config config) {
+        JsonObject json = new JsonObject();
+        if (config != null) {
+            if (config.getConfigSources().iterator().hasNext()) {
+                JsonArray jsonSources = new JsonArray();
+                for (ConfigSource source : config.getConfigSources()) {
+                    JsonObject jsonSource = new JsonObject();
+                    jsonSource.put("source", source.getName())
+                            .put("ordinal", source.getOrdinal());
+                    Set<String> propertyNames = source.getPropertyNames();
+                    if (!propertyNames.isEmpty()) {
+                        SortedSet<String> sortedPropertyNames = new TreeSet<>(propertyNames);
+                        JsonObject jsonProperties = new JsonObject();
+                        for (String propertyName : sortedPropertyNames) {
+                            try {
+                                jsonProperties.put(propertyName, source.getValue(propertyName));
+                            } catch (Throwable t) {
+                                LOGGER.errorf("Cannot get configuration value for '%s': %s",
+                                        propertyName, t.getMessage());
+                            }
+                        }
+                        jsonSource.put("properties", jsonProperties);
+                    }
+                    jsonSources.add(jsonSource);
+                }
+                json.put("sources", jsonSources);
+            }
+        }
+        return json;
+    }
+}

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/devmode/ConfigViewerHandler.java

@@ -0,0 +1,21 @@
+package io.quarkus.vertx.http.runtime.devmode;
+
+import javax.enterprise.inject.spi.CDI;
+
+import io.vertx.core.Handler;
+import io.vertx.core.buffer.Buffer;
+import io.vertx.core.http.HttpServerResponse;
+import io.vertx.core.json.JsonObject;
+import io.vertx.ext.web.RoutingContext;
+
+public class ConfigViewerHandler implements Handler<RoutingContext> {
+
+    @Override
+    public void handle(RoutingContext routingContext) {
+        ConfigHolder configHolder = CDI.current().select(ConfigHolder.class).get();
+        JsonObject json = new ConfigViewer().dump(configHolder.config);
+        HttpServerResponse resp = routingContext.response();
+        resp.putHeader("content-type", "application/json");
+        resp.end(Buffer.buffer(json.encode()));
+    }
+}