Config viewer as part of vertx-http in dev mode

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/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 +1,81 @@
+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.quarkus.runtime.configuration.ExpandingConfigSource;
+
+/**
+ * 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());
+
+    String dump(Config config) {
+        JsonObject json = new JsonObject();
+        if (config != null) {
+            boolean old = ExpandingConfigSource.setExpanding(false);
+            try {
+                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.put(jsonSource);
+                    }
+                    json.put("sources", jsonSources);
+                }
+            } finally {
+                ExpandingConfigSource.setExpanding(old);
+            }
+        }
+        return json.toString(2);
+    }
+}

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

@@ -0,0 +1,20 @@
+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.ext.web.RoutingContext;
+
+public class ConfigViewerHandler implements Handler<RoutingContext> {
+
+    @Override
+    public void handle(RoutingContext routingContext) {
+        ConfigHolder configHolder = CDI.current().select(ConfigHolder.class).get();
+        String json = new ConfigViewer().dump(configHolder.config);
+        HttpServerResponse resp = routingContext.response();
+        resp.putHeader("content-type", "application/json");
+        resp.end(Buffer.buffer(json));
+    }
+}

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

@@ -0,0 +1,69 @@
+/*
+ Copyright (c) 2002 JSON.org
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in all
+ copies or substantial portions of the Software.
+
+ The Software shall be used for Good, not Evil.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ SOFTWARE.
+ */
+package io.quarkus.vertx.http.runtime.devmode;
+
+import java.io.StringWriter;
+import java.util.ArrayList;
+
+class JsonArray {
+
+    private final ArrayList<Object> list;
+
+    JsonArray() {
+        this.list = new ArrayList<Object>();
+    }
+
+    JsonArray put(JsonObject value) {
+        list.add(value);
+        return this;
+    }
+
+    void write(StringWriter writer, int indentFactor, int indent) {
+        boolean needsComma = false;
+        int length = list.size();
+        writer.write('[');
+
+        if (length == 1) {
+            JsonObject.writeValue(writer, list.get(0), indentFactor, indent);
+        } else if (length != 0) {
+            int newIndent = indent + indentFactor;
+            for (int i = 0; i < length; i += 1) {
+                if (needsComma) {
+                    writer.write(',');
+                }
+                if (indentFactor > 0) {
+                    writer.write('\n');
+                }
+                JsonObject.indent(writer, newIndent);
+                JsonObject.writeValue(writer, list.get(i), indentFactor, newIndent);
+                needsComma = true;
+            }
+            if (indentFactor > 0) {
+                writer.write('\n');
+            }
+            JsonObject.indent(writer, indent);
+        }
+        writer.write(']');
+    }
+}