Add auto-configuration for Neo4j driver

This commit adds the support for creating a managed instance of the
Neo4j Java driver. The low-level support for Neo4j is helpful in
situations where the high-level abstraction of Spring Data Neo4j is not
needed.

See gh-22301

buildSrc/src/main/java/org/springframework/boot/build/context/properties/DocumentConfigurationProperties.java

@@ -34,6 +34,7 @@ import org.springframework.boot.build.context.properties.DocumentOptions.Builder
  * {@link Task} used to document auto-configuration classes.
  *
  * @author Andy Wilkinson
+ * @author Michael J. Simons
  */
 public class DocumentConfigurationProperties extends DefaultTask {
 
@@ -80,8 +81,8 @@ public class DocumentConfigurationProperties extends DefaultTask {
 				.addSection("security").withKeyPrefixes("spring.security", "spring.ldap", "spring.session")
 				.addSection("data-migration").withKeyPrefixes("spring.flyway", "spring.liquibase").addSection("data")
 				.withKeyPrefixes("spring.couchbase", "spring.elasticsearch", "spring.h2", "spring.influx",
-						"spring.mongodb", "spring.redis", "spring.dao", "spring.data", "spring.datasource",
-						"spring.jooq", "spring.jdbc", "spring.jpa", "spring.r2dbc")
+						"spring.mongodb", "spring.neo4j", "spring.redis", "spring.dao", "spring.data",
+						"spring.datasource", "spring.jooq", "spring.jdbc", "spring.jpa", "spring.r2dbc")
 				.addOverride("spring.datasource.dbcp2",
 						"Commons DBCP2 specific settings bound to an instance of DBCP2's BasicDataSource")
 				.addOverride("spring.datasource.tomcat",

spring-boot-project/spring-boot-autoconfigure/build.gradle

@@ -180,6 +180,7 @@ dependencies {
 	testImplementation("org.testcontainers:couchbase")
 	testImplementation("org.testcontainers:elasticsearch")
 	testImplementation("org.testcontainers:junit-jupiter")
+	testImplementation("org.testcontainers:neo4j")
 	testImplementation("org.testcontainers:testcontainers")
 	testImplementation("org.yaml:snakeyaml")
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/neo4j/Neo4jAutoConfiguration.java

+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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 org.springframework.boot.autoconfigure.neo4j;
+
+import java.io.File;
+import java.net.URI;
+import java.time.Duration;
+import java.util.Locale;
+import java.util.concurrent.TimeUnit;
+
+import org.neo4j.driver.AuthToken;
+import org.neo4j.driver.AuthTokens;
+import org.neo4j.driver.Config;
+import org.neo4j.driver.Driver;
+import org.neo4j.driver.GraphDatabase;
+import org.neo4j.driver.internal.Scheme;
+import org.neo4j.driver.net.ServerAddressResolver;
+
+import org.springframework.beans.BeanUtils;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.context.properties.source.InvalidConfigurationPropertyValueException;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.util.StringUtils;
+
+/**
+ * Automatic configuration of Neo4j's Java Driver.
+ *
+ * @author Michael J. Simons
+ * @since 2.4.0
+ */
+@Configuration(proxyBeanMethods = false)
+@ConditionalOnClass(Driver.class)
+@EnableConfigurationProperties(Neo4jProperties.class)
+public class Neo4jAutoConfiguration {
+
+	@Bean
+	@ConditionalOnMissingBean(Driver.class)
+	Driver neo4jDriver(Neo4jProperties properties) {
+		AuthToken authToken = asAuthToken(properties.getAuthentication());
+		Config config = asDriverConfig(properties);
+		return GraphDatabase.driver(properties.getUri(), authToken, config);
+	}
+
+	static AuthToken asAuthToken(Neo4jProperties.Authentication authentication) {
+		String username = authentication.getUsername();
+		String password = authentication.getPassword();
+		String kerberosTicket = authentication.getKerberosTicket();
+		String realm = authentication.getRealm();
+
+		boolean hasUsername = StringUtils.hasText(username);
+		boolean hasPassword = StringUtils.hasText(password);
+		boolean hasKerberosTicket = StringUtils.hasText(kerberosTicket);
+
+		if (hasUsername && hasKerberosTicket) {
+			throw new InvalidConfigurationPropertyValueException("org.neo4j.driver.authentication",
+					"username=" + username + ",kerberos-ticket=" + kerberosTicket,
+					"Cannot specify both username and kerberos ticket.");
+		}
+
+		if (hasUsername && hasPassword) {
+			return AuthTokens.basic(username, password, realm);
+		}
+
+		if (hasKerberosTicket) {
+			return AuthTokens.kerberos(kerberosTicket);
+		}
+
+		return AuthTokens.none();
+	}
+
+	static Config asDriverConfig(Neo4jProperties properties) {
+		Config.ConfigBuilder builder = Config.builder();
+		applyTo(builder, properties.getPool());
+		URI uri = properties.getUri();
+		String scheme = (uri != null) ? uri.getScheme() : "bolt";
+		applyTo(builder, properties.getConfig(), isSimpleScheme(scheme));
+
+		return builder.withLogging(new Neo4jSpringJclLogging()).build();
+	}
+
+	static boolean isSimpleScheme(String scheme) {
+		String lowerCaseScheme = scheme.toLowerCase(Locale.ENGLISH);
+		try {
+			Scheme.validateScheme(lowerCaseScheme);
+		}
+		catch (IllegalArgumentException ex) {
+			throw new IllegalArgumentException(String.format("'%s' is not a supported scheme.", scheme));
+		}
+
+		return lowerCaseScheme.equals("bolt") || lowerCaseScheme.equals("neo4j");
+	}
+
+	private static void applyTo(Config.ConfigBuilder builder, Neo4jProperties.PoolSettings poolSettings) {
+		if (poolSettings.isLogLeakedSessions()) {
+			builder.withLeakedSessionsLogging();
+		}
+		builder.withMaxConnectionPoolSize(poolSettings.getMaxConnectionPoolSize());
+		Duration idleTimeBeforeConnectionTest = poolSettings.getIdleTimeBeforeConnectionTest();
+		if (idleTimeBeforeConnectionTest != null) {
+			builder.withConnectionLivenessCheckTimeout(idleTimeBeforeConnectionTest.toMillis(), TimeUnit.MILLISECONDS);
+		}
+		builder.withMaxConnectionLifetime(poolSettings.getMaxConnectionLifetime().toMillis(), TimeUnit.MILLISECONDS);
+		builder.withConnectionAcquisitionTimeout(poolSettings.getConnectionAcquisitionTimeout().toMillis(),
+				TimeUnit.MILLISECONDS);
+
+		if (poolSettings.isMetricsEnabled()) {
+			builder.withDriverMetrics();
+		}
+		else {
+			builder.withoutDriverMetrics();
+		}
+	}
+
+	private static void applyTo(Config.ConfigBuilder builder, Neo4jProperties.DriverSettings driverSettings,
+			boolean withEncryptionAndTrustSettings) {
+		if (withEncryptionAndTrustSettings) {
+			applyEncryptionAndTrustSettings(builder, driverSettings);
+		}
+
+		builder.withConnectionTimeout(driverSettings.getConnectionTimeout().toMillis(), TimeUnit.MILLISECONDS);
+		builder.withMaxTransactionRetryTime(driverSettings.getMaxTransactionRetryTime().toMillis(),
+				TimeUnit.MILLISECONDS);
+
+		Class<? extends ServerAddressResolver> serverAddressResolverClass = driverSettings
+				.getServerAddressResolverClass();
+		if (serverAddressResolverClass != null) {
+			builder.withResolver(BeanUtils.instantiateClass(serverAddressResolverClass));
+		}
+	}
+
+	private static void applyEncryptionAndTrustSettings(Config.ConfigBuilder builder,
+			Neo4jProperties.DriverSettings driverSettings) {
+		if (driverSettings.isEncrypted()) {
+			builder.withEncryption();
+		}
+		else {
+			builder.withoutEncryption();
+		}
+		builder.withTrustStrategy(toInternalRepresentation(driverSettings.getTrustSettings()));
+	}
+
+	static Config.TrustStrategy toInternalRepresentation(Neo4jProperties.TrustSettings trustSettings) {
+		String propertyName = "org.neo4j.driver.config.trust-settings";
+
+		Config.TrustStrategy internalRepresentation;
+		Neo4jProperties.TrustSettings.Strategy strategy = trustSettings.getStrategy();
+		switch (strategy) {
+		case TRUST_ALL_CERTIFICATES:
+			internalRepresentation = Config.TrustStrategy.trustAllCertificates();
+			break;
+		case TRUST_SYSTEM_CA_SIGNED_CERTIFICATES:
+			internalRepresentation = Config.TrustStrategy.trustSystemCertificates();
+			break;
+		case TRUST_CUSTOM_CA_SIGNED_CERTIFICATES:
+			File certFile = trustSettings.getCertFile();
+			if (certFile == null || !certFile.isFile()) {
+				throw new InvalidConfigurationPropertyValueException(propertyName, strategy.name(),
+						"Configured trust strategy requires a certificate file.");
+			}
+			internalRepresentation = Config.TrustStrategy.trustCustomCertificateSignedBy(certFile);
+			break;
+		default:
+			throw new InvalidConfigurationPropertyValueException(propertyName, strategy.name(), "Unknown strategy.");
+		}
+
+		if (trustSettings.isHostnameVerificationEnabled()) {
+			internalRepresentation.withHostnameVerification();
+		}
+		else {
+			internalRepresentation.withoutHostnameVerification();
+		}
+
+		return internalRepresentation;
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/neo4j/Neo4jProperties.java

+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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 org.springframework.boot.autoconfigure.neo4j;
+
+import java.io.File;
+import java.net.URI;
+import java.time.Duration;
+
+import org.neo4j.driver.net.ServerAddressResolver;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+/**
+ * Used to configure an instance of the {@link org.neo4j.driver.Driver Neo4j-Java-Driver}.
+ *
+ * @author Michael J. Simons
+ * @since 2.4.0
+ */
+@ConfigurationProperties(prefix = "spring.neo4j")
+public class Neo4jProperties {
+
+	/**
+	 * Uri this driver should connect to. The driver supports bolt or neo4j as schemes.
+	 */
+	private URI uri = URI.create("bolt://localhost:7687");
+
+	/**
+	 * Authentication the driver is supposed to use. Maybe null.
+	 */
+	private Authentication authentication = new Authentication();
+
+	/**
+	 * Configuration of the connection pool.
+	 */
+	private PoolSettings pool = new PoolSettings();
+
+	/**
+	 * Detailed configuration of the driver.
+	 */
+	private DriverSettings config = new DriverSettings();
+
+	public URI getUri() {
+		return this.uri;
+	}
+
+	public void setUri(URI uri) {
+		this.uri = uri;
+	}
+
+	public Authentication getAuthentication() {
+		return this.authentication;
+	}
+
+	public void setAuthentication(Authentication authentication) {
+		this.authentication = authentication;
+	}
+
+	public PoolSettings getPool() {
+		return this.pool;
+	}
+
+	public void setPool(PoolSettings pool) {
+		this.pool = pool;
+	}
+
+	public DriverSettings getConfig() {
+		return this.config;
+	}
+
+	public void setConfig(DriverSettings config) {
+		this.config = config;
+	}
+
+	public static class Authentication {
+
+		/**
+		 * Login of the user connecting to the database.
+		 */
+		private String username;
+
+		/**
+		 * Password of the user connecting to the database.
+		 */
+		private String password;
+
+		/**
+		 * Realm to connect to.
+		 */
+		private String realm;
+
+		/**
+		 * Kerberos ticket for connecting to the database. Mutual exclusive with a given
+		 * username.
+		 */
+		private String kerberosTicket;
+
+		public String getUsername() {
+			return this.username;
+		}
+
+		public void setUsername(String username) {
+			this.username = username;
+		}
+
+		public String getPassword() {
+			return this.password;
+		}
+
+		public void setPassword(String password) {
+			this.password = password;
+		}
+
+		public String getRealm() {
+			return this.realm;
+		}
+
+		public void setRealm(String realm) {
+			this.realm = realm;
+		}
+
+		public String getKerberosTicket() {
+			return this.kerberosTicket;
+		}
+
+		public void setKerberosTicket(String kerberosTicket) {
+			this.kerberosTicket = kerberosTicket;
+		}
+
+	}
+
+	public static class PoolSettings {
+
+		/**
+		 * Flag, if metrics are enabled.
+		 */
+		private boolean metricsEnabled = false;
+
+		/**
+		 * Flag, if leaked sessions logging is enabled.
+		 */
+		private boolean logLeakedSessions = false;
+
+		/**
+		 * Maximum amount of connections in the connection pool towards a single database.
+		 */
+		private int maxConnectionPoolSize = org.neo4j.driver.internal.async.pool.PoolSettings.DEFAULT_MAX_CONNECTION_POOL_SIZE;
+
+		/**
+		 * Pooled connections that have been idle in the pool for longer than this timeout
+		 * will be tested before they are used again.
+		 */
+		private Duration idleTimeBeforeConnectionTest;
+
+		/**
+		 * Pooled connections older than this threshold will be closed and removed from
+		 * the pool.
+		 */
+		private Duration maxConnectionLifetime = Duration
+				.ofMillis(org.neo4j.driver.internal.async.pool.PoolSettings.DEFAULT_MAX_CONNECTION_LIFETIME);
+
+		/**
+		 * Acquisition of new connections will be attempted for at most configured
+		 * timeout.
+		 */
+		private Duration connectionAcquisitionTimeout = Duration
+				.ofMillis(org.neo4j.driver.internal.async.pool.PoolSettings.DEFAULT_CONNECTION_ACQUISITION_TIMEOUT);
+
+		public boolean isLogLeakedSessions() {
+			return this.logLeakedSessions;
+		}
+
+		public void setLogLeakedSessions(boolean logLeakedSessions) {
+			this.logLeakedSessions = logLeakedSessions;
+		}
+
+		public int getMaxConnectionPoolSize() {
+			return this.maxConnectionPoolSize;
+		}
+
+		public void setMaxConnectionPoolSize(int maxConnectionPoolSize) {
+			this.maxConnectionPoolSize = maxConnectionPoolSize;
+		}
+
+		public Duration getIdleTimeBeforeConnectionTest() {
+			return this.idleTimeBeforeConnectionTest;
+		}
+
+		public void setIdleTimeBeforeConnectionTest(Duration idleTimeBeforeConnectionTest) {
+			this.idleTimeBeforeConnectionTest = idleTimeBeforeConnectionTest;
+		}
+
+		public Duration getMaxConnectionLifetime() {
+			return this.maxConnectionLifetime;
+		}
+
+		public void setMaxConnectionLifetime(Duration maxConnectionLifetime) {
+			this.maxConnectionLifetime = maxConnectionLifetime;
+		}
+
+		public Duration getConnectionAcquisitionTimeout() {
+			return this.connectionAcquisitionTimeout;
+		}
+
+		public void setConnectionAcquisitionTimeout(Duration connectionAcquisitionTimeout) {
+			this.connectionAcquisitionTimeout = connectionAcquisitionTimeout;
+		}
+
+		public boolean isMetricsEnabled() {
+			return this.metricsEnabled;
+		}
+
+		public void setMetricsEnabled(boolean metricsEnabled) {
+			this.metricsEnabled = metricsEnabled;
+		}
+
+	}
+
+	public static class DriverSettings {
+
+		/**
+		 * Flag, if the driver should use encrypted traffic.
+		 */
+		private boolean encrypted = false;
+
+		/**
+		 * Specify how to determine the authenticity of an encryption certificate provided
+		 * by the Neo4j instance we are connecting to.
+		 */
+		private TrustSettings trustSettings = new TrustSettings();
+
+		/**
+		 * Specify socket connection timeout.
+		 */
+		private Duration connectionTimeout = Duration.ofSeconds(30);
+
+		/**
+		 * Specify the maximum time transactions are allowed to retry.
+		 */
+		private Duration maxTransactionRetryTime = Duration
+				.ofMillis(org.neo4j.driver.internal.retry.RetrySettings.DEFAULT.maxRetryTimeMs());
+
+		/**
+		 * Specify a custom server address resolver used by the routing driver to resolve
+		 * the initial address used to create the driver.
+		 */
+		private Class<? extends ServerAddressResolver> serverAddressResolverClass;
+
+		public boolean isEncrypted() {
+			return this.encrypted;
+		}
+
+		public void setEncrypted(boolean encrypted) {
+			this.encrypted = encrypted;
+		}
+
+		public TrustSettings getTrustSettings() {
+			return this.trustSettings;
+		}
+
+		public void setTrustSettings(TrustSettings trustSettings) {
+			this.trustSettings = trustSettings;
+		}
+
+		public Duration getConnectionTimeout() {
+			return this.connectionTimeout;
+		}
+
+		public void setConnectionTimeout(Duration connectionTimeout) {
+			this.connectionTimeout = connectionTimeout;
+		}
+
+		public Duration getMaxTransactionRetryTime() {
+			return this.maxTransactionRetryTime;
+		}
+
+		public void setMaxTransactionRetryTime(Duration maxTransactionRetryTime) {
+			this.maxTransactionRetryTime = maxTransactionRetryTime;
+		}
+
+		public Class<? extends ServerAddressResolver> getServerAddressResolverClass() {
+			return this.serverAddressResolverClass;
+		}
+
+		public void setServerAddressResolverClass(Class<? extends ServerAddressResolver> serverAddressResolverClass) {
+			this.serverAddressResolverClass = serverAddressResolverClass;
+		}
+
+	}
+
+	public static class TrustSettings {
+
+		public enum Strategy {
+
+			TRUST_ALL_CERTIFICATES,
+
+			TRUST_CUSTOM_CA_SIGNED_CERTIFICATES,
+
+			TRUST_SYSTEM_CA_SIGNED_CERTIFICATES
+
+		}
+
+		/**
+		 * Configures the strategy to use use.
+		 */
+		private Strategy strategy = Strategy.TRUST_SYSTEM_CA_SIGNED_CERTIFICATES;
+
+		/**
+		 * File of the certificate to use.
+		 */
+		private File certFile;
+
+		/**
+		 * Flag, if hostname verification is used.
+		 */
+		private boolean hostnameVerificationEnabled = false;
+
+		public Strategy getStrategy() {
+			return this.strategy;
+		}
+
+		public void setStrategy(Strategy strategy) {
+			this.strategy = strategy;
+		}
+
+		public File getCertFile() {
+			return this.certFile;
+		}
+
+		public void setCertFile(File certFile) {
+			this.certFile = certFile;
+		}
+
+		public boolean isHostnameVerificationEnabled() {
+			return this.hostnameVerificationEnabled;
+		}
+
+		public void setHostnameVerificationEnabled(boolean hostnameVerificationEnabled) {
+			this.hostnameVerificationEnabled = hostnameVerificationEnabled;
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/neo4j/Neo4jSpringJclLogging.java

+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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 org.springframework.boot.autoconfigure.neo4j;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.neo4j.driver.Logger;
+import org.neo4j.driver.Logging;
+
+/**
+ * Shim to use Spring JCL implementation, delegating all the hard work of deciding the
+ * underlying system to Spring and Spring Boot.
+ *
+ * @author Michael J. Simons
+ */
+class Neo4jSpringJclLogging implements Logging {
+
+	/**
+	 * This prefix gets added to the log names the driver requests to add some namespace
+	 * around it in a bigger application scenario.
+	 */
+	private static final String AUTOMATIC_PREFIX = "org.neo4j.driver.";
+
+	@Override
+	public Logger getLog(String name) {
+
+		String requestedLog = name;
+		if (!requestedLog.startsWith(AUTOMATIC_PREFIX)) {
+			requestedLog = AUTOMATIC_PREFIX + name;
+		}
+		Log springJclLog = LogFactory.getLog(requestedLog);
+		return new SpringJclLogger(springJclLog);
+	}
+
+	static final class SpringJclLogger implements Logger {
+
+		private final Log delegate;
+
+		SpringJclLogger(Log delegate) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public void error(String message, Throwable cause) {
+			this.delegate.error(message, cause);
+		}
+
+		@Override
+		public void info(String format, Object... params) {
+			this.delegate.info(String.format(format, params));
+		}
+
+		@Override
+		public void warn(String format, Object... params) {
+			this.delegate.warn(String.format(format, params));
+		}
+
+		@Override
+		public void warn(String message, Throwable cause) {
+			this.delegate.warn(message, cause);
+		}
+
+		@Override
+		public void debug(String format, Object... params) {
+			if (isDebugEnabled()) {
+				this.delegate.debug(String.format(format, params));
+			}
+		}
+
+		@Override
+		public void trace(String format, Object... params) {
+			if (isTraceEnabled()) {
+				this.delegate.trace(String.format(format, params));
+			}
+		}
+
+		@Override
+		public boolean isTraceEnabled() {
+			return this.delegate.isTraceEnabled();
+		}
+
+		@Override
+		public boolean isDebugEnabled() {
+			return this.delegate.isDebugEnabled();
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/neo4j/package-info.java

+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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.
+ */
+
+/**
+ * Auto-configuration for Neo4j.
+ */
+package org.springframework.boot.autoconfigure.neo4j;

spring-boot-project/spring-boot-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -100,6 +100,7 @@ org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfigura
 org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,\
 org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration,\
 org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,\
+org.springframework.boot.autoconfigure.neo4j.Neo4jAutoConfiguration,\
 org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
 org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\
 org.springframework.boot.autoconfigure.r2dbc.R2dbcAutoConfiguration,\

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/neo4j/Neo4jAutoConfigurationIntegrationTests.java

+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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 org.springframework.boot.autoconfigure.neo4j;
+
+import org.junit.jupiter.api.Test;
+import org.neo4j.driver.Driver;
+import org.neo4j.driver.Result;
+import org.neo4j.driver.Session;
+import org.neo4j.driver.Transaction;
+import org.testcontainers.containers.Neo4jContainer;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.ImportAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Michael J. Simons
+ */
+@SpringBootTest
+@Testcontainers(disabledWithoutDocker = true)
+class Neo4jAutoConfigurationIntegrationTests {
+
+	@Container
+	private static Neo4jContainer<?> neo4jServer = new Neo4jContainer<>("neo4j:4.0");
+
+	@DynamicPropertySource
+	static void neo4jProperties(DynamicPropertyRegistry registry) {
+		registry.add("spring.neo4j.uri", neo4jServer::getBoltUrl);
+		registry.add("spring.neo4j.authentication.username", () -> "neo4j");
+		registry.add("spring.neo4j.authentication.password", neo4jServer::getAdminPassword);
+	}
+
+	private final Driver driver;
+
+	@Autowired
+	Neo4jAutoConfigurationIntegrationTests(Driver driver) {
+		this.driver = driver;
+	}
+
+	@Test
+	void ensureDriverIsOpen() {
+
+		try (Session session = this.driver.session(); Transaction tx = session.beginTransaction()) {
+			Result statementResult = tx.run("MATCH (n:Thing) RETURN n LIMIT 1");
+			assertThat(statementResult.hasNext()).isFalse();
+			tx.commit();
+		}
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	@ImportAutoConfiguration(Neo4jAutoConfiguration.class)
+	static class TestConfiguration {
+
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/neo4j/Neo4jAutoConfigurationTests.java

+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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 org.springframework.boot.autoconfigure.neo4j;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.neo4j.driver.Driver;
+import org.neo4j.driver.exceptions.ClientException;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.FilteredClassLoader;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.mock;
+import static org.mockito.BDDMockito.when;
+
+/**
+ * @author Michael J. Simons
+ */
+class Neo4jAutoConfigurationTests {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(Neo4jAutoConfiguration.class));
+
+	@Test
+	void shouldRequireAllNeededClasses() {
+
+		this.contextRunner.withPropertyValues("spring.neo4j.uri=bolt://localhost:4711")
+				.withClassLoader(new FilteredClassLoader(Driver.class))
+				.run((ctx) -> assertThat(ctx).doesNotHaveBean(Driver.class));
+	}
+
+	@Test
+	void shouldNotRequireUri() {
+
+		this.contextRunner.run((ctx) -> assertThat(ctx).hasSingleBean(Driver.class));
+	}
+
+	@Test
+	void shouldCreateDriver() {
+
+		this.contextRunner.withPropertyValues("spring.neo4j.uri=bolt://localhost:4711")
+				.run((ctx) -> assertThat(ctx).hasSingleBean(Driver.class));
+	}
+
+	/**
+	 * These tests assert correct configuration behaviour for cases in which one of the
+	 * "advanced" schemes is used to configure the driver. If any of the schemes is used,
+	 * than a contradicting explicit configuration will throw an error.
+	 * @param scheme The scheme to test.
+	 */
+	@ParameterizedTest
+	@ValueSource(strings = { "bolt+s", "bolt+ssc", "neo4j+s", "neo4j+ssc" })
+	void schemesShouldBeApplied(String scheme) {
+
+		this.contextRunner.withPropertyValues("spring.neo4j.uri=" + scheme + "://localhost:4711").run((ctx) -> {
+			assertThat(ctx).hasSingleBean(Driver.class);
+
+			Driver driver = ctx.getBean(Driver.class);
+			assertThat(driver.isEncrypted()).isTrue();
+		});
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	static class WithDriver {
+
+		@Bean
+		Driver driver() {
+			Driver driver = mock(Driver.class);
+			when(driver.metrics()).thenThrow(ClientException.class);
+			return driver;
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/neo4j/TestServerAddressResolver.java

+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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 org.springframework.boot.autoconfigure.neo4j;
+
+import java.util.Collections;
+import java.util.Set;
+
+import org.neo4j.driver.net.ServerAddress;
+import org.neo4j.driver.net.ServerAddressResolver;
+
+/**
+ * Resolver used only for configuration tests.
+ *
+ * @author Michael J. Simons
+ */
+class TestServerAddressResolver implements ServerAddressResolver {
+
+	@Override
+	public Set<ServerAddress> resolve(ServerAddress address) {
+		return Collections.emptySet();
+	}
+
+}

spring-boot-project/spring-boot-dependencies/build.gradle

@@ -1170,6 +1170,13 @@ bom {
 			]
 		}
 	}
+	library("Neo4j", "4.1.0") {
+		group("org.neo4j.driver") {
+			modules = [
+				"neo4j-java-driver"
+			]
+		}
+	}
 	library("Neo4j OGM", "3.2.12") {
 		group("org.neo4j") {
 			modules = [