Many projects that use data require connections to a database. The main way of obtaining connections to a database is to use a datasource.
In Quarkus, the out of the box datasource and connection pooling implementation is Agroal.
This guide will explain how to:
-
configure a datasource, or multiple datasources
-
how to obtain a reference to those datasources in code
Prerequisites
To complete this guide, you need:
-
less than 10 minutes
-
an IDE
-
JDK 1.8+ installed with
JAVA_HOME
configured appropriately -
Apache Maven 3.5.3+
Creating the Maven project
First, we need a new project. Create a new project with the following command:
mvn io.quarkus:quarkus-maven-plugin:0.22.0:create \
-DprojectGroupId=org.acme \
-DprojectArtifactId=agroal-datasources\
-DclassName="org.acme.datasource.GreetingResource" \
-Dpath="/hello"
It generates:
-
the Maven structure
-
a landing page accessible on
http://localhost:8080
-
example
Dockerfile
files for bothnative
andjvm
modes -
the application configuration file
-
an
org.acme.datasource.GreetingResource
resource -
an associated test
Adding maven dependencies
Next, you will need to add the quarkus-agroal
dependency to your project.
You can add it using a simple Maven command:
./mvnw quarkus:add-extension -Dextensions="agroal"
Agroal comes as a transitive dependency of the Hibernate ORM extension so if you are using Hibernate ORM, you don’t need to add the Agroal extension dependency explicitly. |
You will also need to add the database connector library of choice.
Quarkus provides driver extensions for:
-
H2 - jdbc-h2
-
PostgreSQL - jdbc-postgresql
-
MariaDB (and MySQL) - jdbc-mariadb
-
Microsoft SQL Server - jdbc-mssql
In JVM mode, simply adding your driver of choice is sufficient. Extensions are mostly useful to support GraalVM native images. |
As usual, you can install the extension using add-extension
.
To install the PostgreSQL driver dependency for instance, just run the following command:
./mvnw quarkus:add-extension -Dextensions="jdbc-postgresql"
Configuring the datasource
Once the dependencies are added to your pom.xml file, you’ll need to configure Agroal.
This is done in the src/main/resources/application.properties
file.
A viable configuration file would be:
quarkus.datasource.url=jdbc:h2:tcp://localhost/mem:default
quarkus.datasource.driver=org.h2.Driver
quarkus.datasource.username=username-default
quarkus.datasource.min-size=3
quarkus.datasource.max-size=13
There are other configuration options, detailed below.
JDBC URL configurations
Each of the supported databases contains different JDBC URL configuration options. Going into each of those options is beyond the scope of this document, but it gives an overview of each database URL and link to the official documentation.
H2
jdbc:h2:{ {.|mem:}[name] | [file:]fileName | {tcp|ssl}:[//]server[:port][,server2[:port]]/name }[;key=value…]
- Example
-
jdbc:h2:tcp://localhost/~/test
,jdbc:h2:mem:myDB
H2 is an embedded database. It can run as a server, based on a file, or live completely in memory. All of these options are available as listed above. You can find more information at the official documentation.
PostgreSQL
PostgreSQL only runs as a server, as do the rest of the databases below. As such, you must specify connection details, or use the defaults.
jdbc:postgresql:[//][host][:port][/database][?key=value…]
- Example
-
jdbc:postgresql://localhost/test
Defaults for the different parts are as follows:
host
-
localhost
port
-
5432
database
-
same name as the username
The official documentation go into more detail and list optional parameters as well.
MariaDB/MySQL
jdbc:(mysql|mariadb):[replication:|failover:|sequential:|aurora:]//<hostDescription>[,<hostDescription>…]/[database][?<key1>=<value1>[&<key2>=<value2>]]
hostDescription:: <host>[:<portnumber>] or address=(host=<host>)[(port=<portnumber>)][(type=(master|slave))]
- Example
-
jdbc:mysql://localhost:3306/test
You can find more information about this feature and others detailed in the official documentation.
Microsoft SQL Server
Microsoft SQL Server takes a connection URL in the following form:
jdbc:sqlserver://[serverName[\instanceName][:portNumber]][;property=value[;property=value]]
- Example
-
jdbc:sqlserver://localhost:1433;databaseName=AdventureWorks
The Microsoft SQL Server JDBC driver works essentially the same as the others. More details can be found in the official documentation.
Injecting a Datasource
Because Quarkus uses CDI, injecting a datasource is very simple:
@Inject
AgroalDataSource defaultDataSource;
In the above example, the type is AgroalDataSource
which is a subtype of javax.sql.DataSource
.
Because of this, you can also use javax.sql.DataSource
.
Multiple Datasources
Agroal allows you to configure multiple datasources. It works exactly the same way as a single datasource, with one important change: a name.
quarkus.datasource.driver=org.h2.Driver
quarkus.datasource.url=jdbc:h2:tcp://localhost/mem:default
quarkus.datasource.username=username-default
quarkus.datasource.min-size=3
quarkus.datasource.max-size=13
quarkus.datasource.users.driver=org.h2.Driver
quarkus.datasource.users.url=jdbc:h2:tcp://localhost/mem:users
quarkus.datasource.users.username=username1
quarkus.datasource.users.min-size=1
quarkus.datasource.users.max-size=11
quarkus.datasource.inventory.driver=org.h2.Driver
quarkus.datasource.inventory.url=jdbc:h2:tcp://localhost/mem:inventory
quarkus.datasource.inventory.username=username2
quarkus.datasource.inventory.min-size=2
quarkus.datasource.inventory.max-size=12
Notice there’s an extra bit in the key.
The syntax is as follows: quarkus.datasource.[optional name.][datasource property]
.
Named Datasource Injection
When using multiple datasources, each DataSource
also has the io.quarkus.agroal.DataSource
qualifier with the name of the datasource in the property as the value.
Using the above properties to configure three different datasources, you can also inject each one as follows:
@Inject
AgroalDataSource defaultDataSource;
@Inject
@DataSource("users")
AgroalDataSource dataSource1;
@Inject
@DataSource("inventory")
AgroalDataSource dataSource2;
Agroal Configuration Reference
Configuration key | Java type | Example |
---|---|---|
quarkus.datasource.driver |
String (class name) |
org.h2.Driver, com.mysql.jdbc.Driver |
quarkus.datasource.url |
String (JDBC Connection URL) |
jdbc:h2:tcp://localhost/mem:default, jdbc:mysql://hostname:port/dbname |
quarkus.datasource.username |
String |
Fred, Bill, inventory_user |
quarkus.datasource.password |
String |
correct horse battery staple, Tr0ub4dor&3 |
quarkus.datasource.min-size |
Integer |
5, 12, 42 |
quarkus.datasource.max-size |
Integer |
5, 12, 42 |
quarkus.datasource.initial-size |
Integer |
5, 12, 42 |
quarkus.datasource.background-validation-interval |
java.time.Duration |
PT3M, PT56S, |
quarkus.datasource.acquisition-timeout |
java.time.Duration |
PT3M, PT56S - see note below |
quarkus.datasource.leak-detection-interval |
java.time.Duration |
PT3M, PT56S - see note below |
quarkus.datasource.idle-removal-interval |
java.time.Duration |
PT3M, PT56S - see note below |
quarkus.datasource.max-lifetime |
java.time.Duration |
PT3M, PT56S - see note below |
quarkus.datasource.transaction-isolation-level |
io.quarkus.agroal.runtime.TransactionIsolationLevel (enum) |
none, read-committed, read-uncommitted, repeatable-read, serializable |
quarkus.datasource.enable-metrics |
Boolean |
true or false |
quarkus.datasource.xa |
Boolean |
true or false |
The format for durations uses the standard You can also provide duration values starting with a number.
In this case, if the value consists only of a number, the converter treats the value as seconds.
Otherwise, |