For the driver class of org.apache.shardingsphere.driver.ShardingSphereDriver
,
by implementing the SPI of org.apache.shardingsphere.infra.url.ShardingSphereURLLoader
,
allows YAML configuration files to be fetched from multiple sources and File Systems and parsed into ShardingSphere.
If there is no specific statement, the following implementations all use YAML 1.1 as the YAML writing specification.
This does not prevent custom implementations of org.apache.shardingsphere.infra.url.ShardingSphereURLLoader
from being manually converted to YAML from files such as XML or JSON.
After parsing and loading the YAML file into ShardingSphere’s metadata, the next behavior will be determined again through the relevant configuration of Mode Configuration. Discuss two situations,
For the configuration of the Metadata Repository, please refer to Metadata Repository.
The configuration file is xxx.yaml
. When placeholder-type
is none
or is not specified,
the configuration file format is consistent with YAML configuration.
When placeholder-type
exists and is not none
,
the configuration file format is defined in the JDBC URL Parameters
section of this article.
Example:
jdbc:shardingsphere:classpath:config.yaml
jdbc:shardingsphere:classpath:config.yaml?placeholder-type=none
jdbc:shardingsphere:classpath:config.yaml?placeholder-type=environment
jdbc:shardingsphere:classpath:config.yaml?placeholder-type=system_props
The configuration file is xxx.yaml
. When placeholder-type
is none
or is not specified,
the configuration file format is consistent with YAML configuration.
When placeholder-type
exists and is not none
,
the configuration file format is defined in the JDBC URL Parameters
section of this article.
Example:
jdbc:shardingsphere:absolutepath:/path/to/config.yaml
jdbc:shardingsphere:absolutepath:/path/to/config.yaml?placeholder-type=none
jdbc:shardingsphere:absolutepath:/path/to/config.yaml?placeholder-type=environment
jdbc:shardingsphere:absolutepath:/path/to/config.yaml?placeholder-type=system_props
For implementations of org.apache.shardingsphere.infra.url.ShardingSphereURLLoader
,
not all JDBC URL parameters must be parsed,
this involves how to implement org.apache.shardingsphere.infra.url.ShardingSphereURLLoader.load()
.
There is a placeholder-type
attribute for optional loading of configuration files containing dynamic placeholders.
The default value of placeholder-type
is none
.
When placeholder-type
is set to something other than none
, allows setting the value of specific YAML properties via
dynamic placeholders in the involved YAML file, and configuring optional default values.
The name of a dynamic placeholder and its optional default value are separated by ::
and wrapped in the outermost
layer by $${
and }
.
Discuss two situations,
::
.::
exists,
this attribute will be set to empty.The configuration file is xxx.yaml
, and the configuration file format is consistent
with YAML configuration.
Example:
jdbc:shardingsphere:classpath:config.yaml
jdbc:shardingsphere:classpath:config.yaml?placeholder-type=none
jdbc:shardingsphere:absolutepath:/path/to/config.yaml
jdbc:shardingsphere:absolutepath:/path/to/config.yaml?placeholder-type=none
When loading a configuration file containing environment variables,
users need to set placeholder-type
to environment
, which is commonly used in Docker Image deployment scenarios.
The configuration file is xxx.yaml
, and the configuration file format is basically the same as YAML configuration.
Assume that the following set of environment variables exists,
FIXTURE_JDBC_URL
is jdbc:h2:mem:foo_ds_1;DB_CLOSE_DELAY=-1;DATABASE_TO_UPPER=false;MODE=MySQL
.FIXTURE_USERNAME
is sa
.Then for the intercepted fragment of the following YAML file,
ds_1:
dataSourceClassName: com.zaxxer.hikari.HikariDataSource
driverClassName: $${FIXTURE_DRIVER_CLASS_NAME::org.h2.Driver}
jdbcUrl: $${FIXTURE_JDBC_URL::jdbc:h2:mem:foo_ds_do_not_use}
username: $${FIXTURE_USERNAME::}
password: $${FIXTURE_PASSWORD::}
This YAML snippet will be parsed as,
ds_1:
dataSourceClassName: com.zaxxer.hikari.HikariDataSource
driverClassName: org.h2.Driver
jdbcUrl: jdbc:h2:mem:foo_ds_1;DB_CLOSE_DELAY=-1;DATABASE_TO_UPPER=false;MODE=MySQL
username: sa
password:
Example:
jdbc:shardingsphere:classpath:config.yaml?placeholder-type=environment
jdbc:shardingsphere:absolutepath:/path/to/config.yaml?placeholder-type=environment
When loading a configuration file containing system properties, users need to set placeholder-type
to system_props
.
The configuration file is xxx.yaml
, and the configuration file format is basically the same as YAML configuration.
Assume the following set of system properties exists,
fixture.config.driver.jdbc-url
is jdbc:h2:mem:foo_ds_1;DB_CLOSE_DELAY=-1;DATABASE_TO_UPPER=false;MODE=MySQL
.fixture.config.driver.username
is sa
.Then for the intercepted fragment of the following YAML file,
ds_1:
dataSourceClassName: com.zaxxer.hikari.HikariDataSource
driverClassName: $${fixture.config.driver.driver-class-name::org.h2.Driver}
jdbcUrl: $${fixture.config.driver.jdbc-url::jdbc:h2:mem:foo_ds_do_not_use}
username: $${fixture.config.driver.username::}
password: $${fixture.config.driver.password::}
This YAML snippet will be parsed as,
ds_1:
dataSourceClassName: com.zaxxer.hikari.HikariDataSource
driverClassName: org.h2.Driver
jdbcUrl: jdbc:h2:mem:foo_ds_1;DB_CLOSE_DELAY=-1;DATABASE_TO_UPPER=false;MODE=MySQL
username: sa
password:
In real situations, system variables are usually defined dynamically.
Assume that none of the above system variables are defined,
and there is a YAML file config.yaml
containing the above YAML interception fragment,
users can refer to the following method to create a DataSource instance using the HikariCP Java API.
import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import javax.sql.DataSource;
public class ExampleUtils {
public DataSource createDataSource() {
HikariConfig config = new HikariConfig();
config.setDriverClassName("org.apache.shardingsphere.driver.ShardingSphereDriver");
config.setJdbcUrl("jdbc:shardingsphere:classpath:config.yaml?placeholder-type=system_props");
try {
assert null == System.getProperty("fixture.config.driver.jdbc-url");
assert null == System.getProperty("fixture.config.driver.username");
System.setProperty("fixture.config.driver.jdbc-url", "jdbc:h2:mem:foo_ds_1;DB_CLOSE_DELAY=-1;DATABASE_TO_UPPER=false;MODE=MySQL");
System.setProperty("fixture.config.driver.username", "sa");
return new HikariDataSource(config);
} finally {
System.clearProperty("fixture.config.driver.jdbc-url");
System.clearProperty("fixture.config.driver.username");
}
}
}
Example:
jdbc:shardingsphere:classpath:config.yaml?placeholder-type=system_props
jdbc:shardingsphere:absolutepath:/path/to/config.yaml?placeholder-type=system_props
For details, please refer to https://github.com/apache/shardingsphere-plugin.