Handle database down in Spring Boot

Question

I would like to test on my system if the database is down with Spring Boot. I have written a rest call for testing. When the database is up, it return "test" which is correct result. But the database is down, it return nothing. The Goal is to make it to return "test" even the database is down. Below is the error

2020-04-27 17:27:00.003 ERROR 9536     [] --- [pool-1-thread-1] o.s.s.s.TaskUtils$LoggingErrorHandler    : Unexpected error occurred in scheduled task.
org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
        at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:450)
        at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:378)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:137)
        at org.springframework.session.jdbc.JdbcOperationsSessionRepository.cleanUpExpiredSessions(JdbcOperationsSessionRepository.java:589)
        at org.springframework.session.jdbc.config.annotation.web.http.JdbcHttpSessionConfiguration.lambda$configureTasks$0(JdbcHttpSessionConfiguration.java:194)
        at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
        at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:93)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
        at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:48)
        at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
        at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111)
        at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97)
        at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:109)
        at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getPhysicalConnection(LogicalConnectionManagedImpl.java:136)
        at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getConnectionForTransactionManagement(LogicalConnectionManagedImpl.java:254)
        at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:262)
        at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:214)
        at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:56)
        at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:162)
        at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:400)
        ... 13 common frames omitted
Caused by: java.sql.SQLTransientConnectionException: HikariCP - Connection is not available, request timed out after 60000ms.
        at com.zaxxer.hikari.pool.HikariPool.createTimeoutException(HikariPool.java:669)
        at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:183)
        at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:148)
        at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:128)
        at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122)
        at org.hibernate.internal.NonContextualJdbcConnectionAccess.obtainConnection(NonContextualJdbcConnectionAccess.java:35)
        at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:106)
        ... 20 common frames omitted
Caused by: org.postgresql.util.PSQLException: Connection to X:X:X:X:xxxx refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
        at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:280)
        at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
        at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:195)
        at org.postgresql.Driver.makeConnection(Driver.java:454)
        at org.postgresql.Driver.connect(Driver.java:256)
        at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:117)
        at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:123)
        at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:365)
        at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:194)
        at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:460)
        at com.zaxxer.hikari.pool.HikariPool.access$100(HikariPool.java:71)
        at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:699)
        at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:685)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        ... 3 common frames omitted
Caused by: java.net.ConnectException: Connection refused (Connection refused)
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
        at java.net.Socket.connect(Socket.java:589)
        at org.postgresql.core.PGStream.<init>(PGStream.java:70)
        at org.postgresql.core.v3.ConnectionFactoryImpl.tryConnect(ConnectionFactoryImpl.java:91)
        at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:192)
        ... 16 common frames omitted

And the test controller is in below

@RestController
public class TestController {
    @GetMapping(value = "/test")
    public String test() {
        System.out.println("test");
        return "Test";
    }

}

the application.properties is like below

spring.datasource.hikari.maximumPoolSize=10
spring.datasource.hikari.idleTimeout=50000
spring.datasource.hikari.maxLifetime=2000000
spring.datasource.hikari.connectionTimeout=60000
spring.datasource.continue-on-error=true
spring.datasource.initialization-mode=never
spring.datasource.hikari.pool-name=KlmsHikariCP
spring.datasource.hikari.connection-test-query=SELECT 1
spring.datasource.hikari.initialization-fail-timeout= -1
spring.datasource.hikari.isolate-internal-queries=true
spring.datasource.hikari.allow-pool-suspension=true
spring.datasource.test-while-idle=true
spring.datasource.test-on-borrow=true
spring.datasource.test-on-return=false
spring.datasource.validation-interval=40000
spring.datasource.validation-query=SELECT 1 FROM DUAL
spring.datasource.time-between-eviction-runs-millis=5000
spring.datasource.min-evictable-idle-time-millis=5000
spring.datasource.remove-abandoned=true
spring.datasource.remove-abandoned-timeout=3
spring.datasource.log-abandoned=true
spring.datasource.log-validation-errors=true


################### Hibernate Configuration ##########################
spring.jpa.hibernate.ddl-auto=none
spring.jpa.show-sql=false
spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults=true
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect

Answer 1

Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

Answer 2

Cause of error if Caused by: org.postgresql.util.PSQLException: Connection to X:X:X:X:xxxx refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

Please make sure the database host and port in your application.properties file are mentioned and are correct and also the database instance is up and running in mentioned host.

Answer 3

Do you mean during the startup of Spring or while the application is running?

Your RestController currently does not access the DB so I fail to see how the DB connection could result in errors and if the DB is down the controller should return "Test".

If you mean during startup you can try:

spring.datasource.continue-on-error=true