Add support for Dev Services inside Neo4j module.

This change adds one additional processor that conditionally (when docker is working and Neo4j is not reachable on the default address) starts up a Neo4j Test container based on the latest image.

Tests have been added that will be executed when docker is enabled.

The existing functional integration tests won't be affected as they use explicit configuration.

docs/src/main/asciidoc/neo4j.adoc

@@ -167,6 +167,7 @@ The Neo4j driver can be configured with standard Quarkus properties:
 [source,properties]
 .src/main/resources/application.properties
 ----
+# Those are the default values and are implicitly assumed
 quarkus.neo4j.uri = bolt://localhost:7687
 quarkus.neo4j.authentication.username = neo4j
 quarkus.neo4j.authentication.password = secret
@@ -176,6 +177,24 @@ You'll recognize the authentication here that you passed on to the docker comman
 
 Having done that, the driver is ready to use, there are however other configuration options, detailed below.
 
+[[dev-services]]
+=== Dev Services (Configuration Free Databases)
+
+Quarkus supports a feature called Dev Services that allows you to create various datasources without any config.
+In the case of Neo4j this support applies to the single Neo4j driver instance.
+Dev Services will bring up a Neo4j container if you didn't explicit add the default values or configured custom values for
+any of `quarkus.neo4j.uri`, `quarkus.neo4j.authentication.username` or `quarkus.neo4j.authentication.password`.
+If Neo4j seems to be reachable via the default properties, Dev Services will also step back.
+
+Otherwise, Quarkus will automatically start a Neo4j container when running tests or dev-mode,
+and automatically configure the connection.
+
+When running the production version of the application, the Neo4j connection need to be configured as normal,
+so if you want to include a production database config in your `application.properties` and continue to use Dev Services
+we recommend that you use the `%prod.` profile to define your Neo4j settings.
+
+include::{generated-dir}/config/quarkus-neo4j-config-group-dev-services-build-time-config.adoc[opts=optional, leveloffset=+1]
+
 == Using the driver
 
 === General remarks

extensions/neo4j/deployment/pom.xml

@@ -29,6 +29,36 @@
             <groupId>io.quarkus</groupId>
             <artifactId>quarkus-neo4j</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>neo4j</artifactId>
+            <exclusions>
+                <exclusion>
+                    <groupId>junit</groupId>
+                    <artifactId>junit</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-devservices-common</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-junit5-internal</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -45,6 +75,15 @@
                     </annotationProcessorPaths>
                 </configuration>
             </plugin>
+            <plugin>
+                <!-- See https://github.com/junit-team/junit5/issues/1377#issuecomment-381964988 -->
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration combine.self="append">
+                    <excludes>
+                        <exclude/>
+                    </excludes>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 </project>

extensions/neo4j/deployment/src/main/java/io/quarkus/neo4j/deployment/BoltHandshaker.java

@@ -0,0 +1,77 @@
+package io.quarkus.neo4j.deployment;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.time.Duration;
+
+/**
+ * This implements the protocol version negotiation of bolt. Testing to see if in address will respond to this is a
+ * quick way to find out if it's a running bolt server.
+ * <p>
+ * This class first appeared in https://github.com/michael-simons/junit-jupiter-causal-cluster-testcontainer-extension
+ * by Andrew Jefferson and Michael Simons
+ */
+final class BoltHandshaker {
+
+    private static final int magicToken = 1616949271;
+
+    // Versions message that cannot be matched because it is all zeros.
+    private static final byte[] versionsMessage = {
+            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00
+    };
+
+    private final String address;
+    private final int port;
+
+    BoltHandshaker(String address, int port) {
+        this.address = address;
+        this.port = port;
+    }
+
+    private boolean doBoltHandshake(String address, int port, int timeoutMillis) {
+
+        try (Socket socket = new Socket()) {
+
+            // Set the socket timeout for blocking operations
+            socket.setSoTimeout(timeoutMillis);
+
+            // Connects this socket to the server (also with the specified timeout value).
+            socket.connect(new InetSocketAddress(address, port), timeoutMillis);
+
+            DataOutputStream dOut = new DataOutputStream(socket.getOutputStream());
+            DataInputStream dIn = new DataInputStream(socket.getInputStream());
+
+            // Send magic token (0x6060B017)
+            dOut.writeInt(magicToken);
+            dOut.flush();
+
+            // Send 4 supported versions
+            // Except we don't support any versions and communicate that by sending all zeros
+            dOut.write(versionsMessage);
+            dOut.flush();
+
+            // Receive agreed version
+            // It should be 0 because there are no possible versions we can agree on
+            int response = dIn.readInt();
+            assert response == 0;
+
+            // Because we cannot agree on a version the server should close its side of the connection
+            // resulting in EOF (-1) on all subsequent reads.
+            return dIn.read() == -1;
+        } catch (IOException exception) {
+            // Return false if handshake fails
+            return false;
+        }
+    }
+
+    boolean isBoltPortReachable(Duration timeout) {
+        int timeoutMillis = Math.toIntExact(timeout.toMillis());
+        return doBoltHandshake(address, port, timeoutMillis);
+    }
+}

extensions/neo4j/deployment/src/main/java/io/quarkus/neo4j/deployment/DevServicesBuildTimeConfig.java

@@ -0,0 +1,32 @@
+package io.quarkus.neo4j.deployment;
+
+import java.util.Map;
+import java.util.Optional;
+
+import io.quarkus.runtime.annotations.ConfigGroup;
+import io.quarkus.runtime.annotations.ConfigItem;
+
+@ConfigGroup
+public class DevServicesBuildTimeConfig {
+
+    /**
+     * If DevServices has been explicitly enabled or disabled. DevServices is generally enabled
+     * by default, unless there is an existing configuration present.
+     * When DevServices is enabled Quarkus will attempt to automatically configure and start
+     * a database when running in Dev or Test mode.
+     */
+    @ConfigItem
+    public Optional<Boolean> enabled = Optional.empty();
+
+    /**
+     * The container image name to use, for container based DevServices providers.
+     */
+    @ConfigItem(defaultValue = "neo4j:4.3")
+    public String imageName;
+
+    /**
+     * Additional environment entries that can be added to the container before its start.
+     */
+    @ConfigItem
+    public Map<String, String> additionalEnv;
+}

extensions/neo4j/deployment/src/main/java/io/quarkus/neo4j/deployment/Neo4jBuildTimeConfig.java

@@ -6,9 +6,16 @@
 
 @ConfigRoot(name = "neo4j", phase = ConfigPhase.BUILD_TIME)
 public class Neo4jBuildTimeConfig {
+
     /**
-     * Whether or not an health check is published in case the smallrye-health extension is present.
+     * Whether a health check is published in case the smallrye-health extension is present.
      */
     @ConfigItem(name = "health.enabled", defaultValue = "true")
     public boolean healthEnabled;
+
+    /**
+     * Configuration for DevServices. DevServices allows Quarkus to automatically start a Neo4j instance in dev and test mode.
+     */
+    @ConfigItem
+    public DevServicesBuildTimeConfig devservices;
 }

extensions/neo4j/deployment/src/main/java/io/quarkus/neo4j/deployment/Neo4jDevServiceBuildItem.java

@@ -0,0 +1,6 @@
+package io.quarkus.neo4j.deployment;
+
+import io.quarkus.builder.item.SimpleBuildItem;
+
+public final class Neo4jDevServiceBuildItem extends SimpleBuildItem {
+}