feat: Provide ConnectionDetails without retrieving the whole chain …

…of applied migrations.

neo4j-migrations-cli/pom.xml

@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>1.3.4-SNAPSHOT</version>
+		<version>1.4.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>neo4j-migrations-cli</artifactId>

neo4j-migrations-core/pom.xml

@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>1.3.4-SNAPSHOT</version>
+		<version>1.4.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>neo4j-migrations</artifactId>

neo4j-migrations-core/src/main/java/ac/simons/neo4j/migrations/core/ChainBuilder.java

@@ -26,13 +26,8 @@
 import java.util.Map;
 import java.util.Optional;
 
-import org.neo4j.driver.Record;
 import org.neo4j.driver.Result;
 import org.neo4j.driver.Session;
-import org.neo4j.driver.internal.util.ServerVersion;
-import org.neo4j.driver.summary.DatabaseInfo;
-import org.neo4j.driver.summary.ResultSummary;
-import org.neo4j.driver.summary.ServerInfo;
 import org.neo4j.driver.types.IsoDuration;
 import org.neo4j.driver.types.Node;
 import org.neo4j.driver.types.Path;
@@ -81,55 +76,7 @@ MigrationChain buildChain(MigrationContext context, List<Migration> discoveredMi
 	MigrationChain buildChain(MigrationContext context, List<Migration> discoveredMigrations, boolean detailedCauses) {
 
 		final Map<MigrationVersion, Element> elements = buildChain0(context, discoveredMigrations, detailedCauses);
-
-		class ExtendedResultSummary {
-			final boolean showCurrentUserExists;
-			final ServerVersion version;
-			final ServerInfo server;
-			final DatabaseInfo database;
-
-			ExtendedResultSummary(boolean showCurrentUserExists, ServerVersion version, ResultSummary actualSummary) {
-				this.showCurrentUserExists = showCurrentUserExists;
-				this.version = version;
-				this.server = actualSummary.server();
-				this.database = actualSummary.database();
-			}
-		}
-
-		try (Session session = context.getSchemaSession()) {
-
-			// Auth maybe disabled. In such cases, we cannot get the current user.
-			ExtendedResultSummary databaseInformation = session.readTransaction(tx -> {
-				Result result = tx.run(""
-					+ "CALL dbms.procedures() YIELD name "
-					+ "WHERE name = 'dbms.showCurrentUser' "
-					+ "WITH count(*) > 0 AS showCurrentUserExists "
-					+ "CALL dbms.components() YIELD versions "
-					+ "RETURN showCurrentUserExists, 'Neo4j/' + versions[0] AS version"
-				);
-				Record singleResultRecord = result.single();
-				boolean showCurrentUserExists = singleResultRecord.get("showCurrentUserExists").asBoolean();
-				ServerVersion version = ServerVersion.version(singleResultRecord.get("version").asString());
-				ResultSummary summary = result.consume();
-				return new ExtendedResultSummary(showCurrentUserExists, version, summary);
-			});
-
-			String username = "anonymous";
-			if (databaseInformation.showCurrentUserExists) {
-
-				username = session.readTransaction(tx -> tx.run(""
-					+ "CALL dbms.procedures() YIELD name "
-					+ "WHERE name = 'dbms.showCurrentUser' "
-					+ "CALL dbms.showCurrentUser() YIELD username RETURN username"
-				).single().get("username").asString());
-			}
-
-			ServerInfo serverInfo = databaseInformation.server;
-			String schemaDatabase = databaseInformation.database == null ? null : databaseInformation.database.name();
-			String targetDatabase = context.getConfig().getMigrationTargetIn(context).orElse(schemaDatabase);
-			return new DefaultMigrationChain(serverInfo.address(), databaseInformation.version.toString(),
-				username, targetDatabase, schemaDatabase, elements);
-		}
+		return new DefaultMigrationChain(context.getConnectionDetails(), elements);
 	}
 
 	private Map<MigrationVersion, Element> buildChain0(MigrationContext context, List<Migration> discoveredMigrations, boolean detailedCauses) {
@@ -205,56 +152,44 @@ private Map<MigrationVersion, Element> getChainOfAppliedMigrations(MigrationCont
 
 	private static class DefaultMigrationChain implements MigrationChain {
 
-		private final String serverAdress;
-
-		private final String serverVersion;
-
-		private final String username;
-
-		private final String databaseName;
-
-		private final String schemaDatabaseName;
+		private final ConnectionDetails connectionDetailsDelegate;
 
 		private final Map<MigrationVersion, Element> elements;
 
-		DefaultMigrationChain(String serverAdress, String serverVersion, String username, String databaseName, String schemaDatabaseName,
-			Map<MigrationVersion, Element> elements) {
-			this.serverAdress = serverAdress;
-			this.serverVersion = serverVersion;
-			this.username = username;
-			this.databaseName = databaseName;
-			this.schemaDatabaseName = schemaDatabaseName;
+		DefaultMigrationChain(ConnectionDetails connectionDetailsDelegate, Map<MigrationVersion, Element> elements) {
+			this.connectionDetailsDelegate = connectionDetailsDelegate;
 			this.elements = elements;
 		}
 
 		@Override
 		public String getServerAddress() {
-			return serverAdress;
+			return connectionDetailsDelegate.getServerAddress();
 		}
 
 		@Override
 		public String getServerVersion() {
-			return serverVersion;
+			return connectionDetailsDelegate.getServerVersion();
 		}
 
-		@Override public String getUsername() {
-			return username;
-		}
-
-		@SuppressWarnings("deprecation")
 		@Override
-		public String getDatabaseName() {
-			return databaseName;
+		public String getUsername() {
+			return connectionDetailsDelegate.getUsername();
 		}
 
 		@Override
 		public Optional<String> getOptionalDatabaseName() {
-			return Optional.ofNullable(databaseName);
+			return connectionDetailsDelegate.getOptionalDatabaseName();
 		}
 
 		@Override
 		public Optional<String> getOptionalSchemaDatabaseName() {
-			return Optional.ofNullable(schemaDatabaseName);
+			return connectionDetailsDelegate.getOptionalSchemaDatabaseName();
+		}
+
+		@SuppressWarnings("deprecation")
+		@Override
+		public String getDatabaseName() {
+			return getOptionalDatabaseName().orElse(null);
 		}
 
 		@Override

neo4j-migrations-core/src/main/java/ac/simons/neo4j/migrations/core/ConnectionDetails.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2020-2022 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 ac.simons.neo4j.migrations.core;
+
+import java.util.Optional;
+
+/**
+ * Provides detailed information about the connection being used when invoking any method that talks to the database.
+ *
+ * @author Michael J. Simons
+ * @soundtrack Snoop Dogg - Doggystyle
+ * @since 1.4.0
+ */
+public interface ConnectionDetails {
+
+	/**
+	 * @return the address of the server used
+	 */
+	String getServerAddress();
+
+	/**
+	 * @return the Neo4j version the server is running
+	 */
+	String getServerVersion();
+
+	/**
+	 * @return the Neo4j user that ran the migrations
+	 */
+	String getUsername();
+
+	/**
+	 * @return the database if applicable (Neo4j 4.0 and up)
+	 */
+	Optional<String> getOptionalDatabaseName();
+
+	/**
+	 * @return the database if applicable (Neo4j 4.0 and up)
+	 */
+	Optional<String> getOptionalSchemaDatabaseName();
+}

neo4j-migrations-core/src/main/java/ac/simons/neo4j/migrations/core/DefaultConnectionDetails.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2020-2022 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 ac.simons.neo4j.migrations.core;
+
+import java.util.Optional;
+
+/**
+ * @author Michael J. Simons
+ * @soundtrack Snoop Dogg - Doggystyle
+ * @since 1.4.0
+ */
+final class DefaultConnectionDetails implements ConnectionDetails {
+
+	private final String serverAddress;
+
+	private final String serverVersion;
+
+	private final String username;
+
+	private final String databaseName;
+
+	private final String schemaDatabaseName;
+
+	DefaultConnectionDetails(String serverAddress, String serverVersion, String username,
+		String databaseName, String schemaDatabaseName) {
+		this.serverAddress = serverAddress;
+		this.serverVersion = serverVersion;
+		this.username = username;
+		this.databaseName = databaseName;
+		this.schemaDatabaseName = schemaDatabaseName;
+	}
+
+	@Override
+	public String getServerAddress() {
+		return serverAddress;
+	}
+
+	@Override
+	public String getServerVersion() {
+		return serverVersion;
+	}
+
+	@Override
+	public String getUsername() {
+		return username;
+	}
+
+	@Override
+	public Optional<String> getOptionalDatabaseName() {
+		return Optional.ofNullable(databaseName);
+	}
+
+	@Override
+	public Optional<String> getOptionalSchemaDatabaseName() {
+		return Optional.ofNullable(schemaDatabaseName);
+	}
+}

neo4j-migrations-core/src/main/java/ac/simons/neo4j/migrations/core/DefaultMigrationContext.java

@@ -25,8 +25,14 @@
 import org.neo4j.driver.AccessMode;
 import org.neo4j.driver.Bookmark;
 import org.neo4j.driver.Driver;
+import org.neo4j.driver.Record;
+import org.neo4j.driver.Result;
 import org.neo4j.driver.Session;
 import org.neo4j.driver.SessionConfig;
+import org.neo4j.driver.internal.util.ServerVersion;
+import org.neo4j.driver.summary.DatabaseInfo;
+import org.neo4j.driver.summary.ResultSummary;
+import org.neo4j.driver.summary.ServerInfo;
 
 /**
  * Default implementation of the {@link MigrationContext}, including the logic of wrapping driver and blocking sessions
@@ -54,6 +60,8 @@ private static Method findWithImpersonatedUser() {
 
 	private final Driver driver;
 
+	private volatile ConnectionDetails connectionDetails;
+
 	DefaultMigrationContext(MigrationsConfig config, Driver driver) {
 
 		if (config.getOptionalImpersonatedUser().isPresent() && WITH_IMPERSONATED_USER == null) {
@@ -125,6 +133,74 @@ public Session getSchemaSession() {
 		return getDriver().session(getSessionConfig(applySchemaDatabase));
 	}
 
+	@Override
+	public ConnectionDetails getConnectionDetails() {
+
+		ConnectionDetails availableConnectionDetails = this.connectionDetails;
+		if (availableConnectionDetails == null) {
+			synchronized (this) {
+				availableConnectionDetails = this.connectionDetails;
+				if (availableConnectionDetails == null) {
+					this.connectionDetails = getConnectionDetails0();
+					availableConnectionDetails = this.connectionDetails;
+				}
+			}
+		}
+		return availableConnectionDetails;
+	}
+
+	private ConnectionDetails getConnectionDetails0() {
+
+		class ExtendedResultSummary {
+			final boolean showCurrentUserExists;
+			final ServerVersion version;
+			final ServerInfo server;
+			final DatabaseInfo database;
+
+			ExtendedResultSummary(boolean showCurrentUserExists, ServerVersion version, ResultSummary actualSummary) {
+				this.showCurrentUserExists = showCurrentUserExists;
+				this.version = version;
+				this.server = actualSummary.server();
+				this.database = actualSummary.database();
+			}
+		}
+
+		try (Session session = this.getSchemaSession()) {
+
+			// Auth maybe disabled. In such cases, we cannot get the current user.
+			ExtendedResultSummary databaseInformation = session.readTransaction(tx -> {
+				Result result = tx.run(""
+					+ "CALL dbms.procedures() YIELD name "
+					+ "WHERE name = 'dbms.showCurrentUser' "
+					+ "WITH count(*) > 0 AS showCurrentUserExists "
+					+ "CALL dbms.components() YIELD versions "
+					+ "RETURN showCurrentUserExists, 'Neo4j/' + versions[0] AS version"
+				);
+				Record singleResultRecord = result.single();
+				boolean showCurrentUserExists = singleResultRecord.get("showCurrentUserExists").asBoolean();
+				ServerVersion version = ServerVersion.version(singleResultRecord.get("version").asString());
+				ResultSummary summary = result.consume();
+				return new ExtendedResultSummary(showCurrentUserExists, version, summary);
+			});
+
+			String username = "anonymous";
+			if (databaseInformation.showCurrentUserExists) {
+
+				username = session.readTransaction(tx -> tx.run(""
+					+ "CALL dbms.procedures() YIELD name "
+					+ "WHERE name = 'dbms.showCurrentUser' "
+					+ "CALL dbms.showCurrentUser() YIELD username RETURN username"
+				).single().get("username").asString());
+			}
+
+			ServerInfo serverInfo = databaseInformation.server;
+			String schemaDatabase = databaseInformation.database == null ? null : databaseInformation.database.name();
+			String targetDatabase = getConfig().getMigrationTargetIn(this).orElse(schemaDatabase);
+			return new DefaultConnectionDetails(serverInfo.address(), databaseInformation.version.toString(), username,
+				targetDatabase, schemaDatabase);
+		}
+	}
+
 	/**
 	 * This proxy catches all calls to {@link Driver#session()} and {@link Driver#session(SessionConfig)} and
 	 * makes sure that a session config with the current set of bookmarks is used correctly.