Use query-less datasource validation by default

This commit changes DataSourceHealthIndicator to validate the connection
rather than issuing a query to the database. If a custom validation
query is specified, it uses that as before.

Closes gh-17582

Author: snicoll

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/jdbc/DataSourceHealthIndicator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * 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.
@@ -28,7 +28,7 @@
 import org.springframework.boot.actuate.health.AbstractHealthIndicator;
 import org.springframework.boot.actuate.health.Health;
 import org.springframework.boot.actuate.health.HealthIndicator;
-import org.springframework.boot.jdbc.DatabaseDriver;
+import org.springframework.boot.actuate.health.Status;
 import org.springframework.dao.support.DataAccessUtils;
 import org.springframework.jdbc.IncorrectResultSetColumnCountException;
 import org.springframework.jdbc.core.ConnectionCallback;
@@ -51,8 +51,6 @@
  */
 public class DataSourceHealthIndicator extends AbstractHealthIndicator implements InitializingBean {
 
-	private static final String DEFAULT_QUERY = "SELECT 1";
-
 	private DataSource dataSource;
 
 	private String query;
@@ -104,17 +102,27 @@ protected void doHealthCheck(Health.Builder builder) throws Exception {
 	}
 
 	private void doDataSourceHealthCheck(Health.Builder builder) throws Exception {
-		String product = getProduct();
-		builder.up().withDetail("database", product);
-		String validationQuery = getValidationQuery(product);
-		try {
-			// Avoid calling getObject as it breaks MySQL on Java 7
-			List<Object> results = this.jdbcTemplate.query(validationQuery, new SingleColumnRowMapper());
-			Object result = DataAccessUtils.requiredSingleResult(results);
-			builder.withDetail("result", result);
+		builder.up().withDetail("database", getProduct());
+		String validationQuery = this.query;
+		if (StringUtils.hasText(validationQuery)) {
+			try {
+				// Avoid calling getObject as it breaks MySQL on Java 7
+				List<Object> results = this.jdbcTemplate.query(validationQuery, new SingleColumnRowMapper());
+				Object result = DataAccessUtils.requiredSingleResult(results);
+				builder.withDetail("result", result);
+			}
+			finally {
+				builder.withDetail("validationQuery", validationQuery);
+			}
 		}
-		finally {
-			builder.withDetail("validationQuery", validationQuery);
+		else {
+			try {
+				boolean valid = isConnectionValid();
+				builder.status((valid) ? Status.UP : Status.DOWN);
+			}
+			finally {
+				builder.withDetail("validationQuery", "isValid()");
+			}
 		}
 	}
 
@@ -126,16 +134,12 @@ private String getProduct(Connection connection) throws SQLException {
 		return connection.getMetaData().getDatabaseProductName();
 	}
 
-	protected String getValidationQuery(String product) {
-		String query = this.query;
-		if (!StringUtils.hasText(query)) {
-			DatabaseDriver specific = DatabaseDriver.fromProductName(product);
-			query = specific.getValidationQuery();
-		}
-		if (!StringUtils.hasText(query)) {
-			query = DEFAULT_QUERY;
-		}
-		return query;
+	private Boolean isConnectionValid() {
+		return this.jdbcTemplate.execute((ConnectionCallback<Boolean>) this::isConnectionValid);
+	}
+
+	private Boolean isConnectionValid(Connection connection) throws SQLException {
+		return connection.isValid(0);
 	}
 
 	/**
@@ -149,8 +153,8 @@ public void setDataSource(DataSource dataSource) {
 
 	/**
 	 * Set a specific validation query to use to validate a connection. If none is set, a
-	 * default validation query is used.
-	 * @param query the query
+	 * validation based on {@link Connection#isValid(int)} is used.
+	 * @param query the validation query to use
 	 */
 	public void setQuery(String query) {
 		this.query = query;

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/jdbc/DataSourceHealthIndicatorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * 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.
@@ -17,6 +17,7 @@
 package org.springframework.boot.actuate.jdbc;
 
 import java.sql.Connection;
+import java.sql.SQLException;
 
 import javax.sql.DataSource;
 
@@ -26,7 +27,6 @@
 
 import org.springframework.boot.actuate.health.Health;
 import org.springframework.boot.actuate.health.Status;
-import org.springframework.boot.jdbc.DatabaseDriver;
 import org.springframework.boot.jdbc.EmbeddedDatabaseConnection;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.datasource.SingleConnectionDataSource;
@@ -69,8 +69,8 @@ void healthIndicatorWithDefaultSettings() {
 		this.indicator.setDataSource(this.dataSource);
 		Health health = this.indicator.health();
 		assertThat(health.getStatus()).isEqualTo(Status.UP);
-		assertThat(health.getDetails()).containsOnly(entry("database", "HSQL Database Engine"), entry("result", 1L),
-				entry("validationQuery", DatabaseDriver.HSQLDB.getValidationQuery()));
+		assertThat(health.getDetails()).containsOnly(entry("database", "HSQL Database Engine"),
+				entry("validationQuery", "isValid()"));
 	}
 
 	@Test
@@ -109,4 +109,18 @@ void healthIndicatorCloseConnection() throws Exception {
 		verify(connection, times(2)).close();
 	}
 
+	@Test
+	void healthIndicatorWithConnectionValidationFailure() throws SQLException {
+		DataSource dataSource = mock(DataSource.class);
+		Connection connection = mock(Connection.class);
+		given(connection.isValid(0)).willReturn(false);
+		given(connection.getMetaData()).willReturn(this.dataSource.getConnection().getMetaData());
+		given(dataSource.getConnection()).willReturn(connection);
+		this.indicator.setDataSource(dataSource);
+		Health health = this.indicator.health();
+		assertThat(health.getStatus()).isEqualTo(Status.DOWN);
+		assertThat(health.getDetails()).containsOnly(entry("database", "HSQL Database Engine"),
+				entry("validationQuery", "isValid()"));
+	}
+
 }