SPI Overview

Plugins can provide additional Connectors, , Functions and . In particular, connectors are the source of all data for queries in Presto: they back each catalog available to Presto.

The SPI source can be found in the directory in the root of the Presto source tree.

Each plugin identifies an entry point: an implementation of the Plugin interface. This class name is provided to Presto via the standard Java ServiceLoader interface: the classpath contains a resource file named com.facebook.presto.spi.Plugin in the META-INF/services directory. The content of this file is a single line listing the name of the plugin class:

The Plugin interface is a good starting place for developers looking to understand the Presto SPI. It contains access methods to retrieve various classes that a Plugin can provide. For example, the method is a top-level function that Presto calls to retrieve a ConnectorFactory when Presto is ready to create an instance of a connector to back a catalog. There are similar methods for Type, ParametricType, Function, SystemAccessControl, and EventListenerFactory objects.

Plugins depend on the SPI from Presto:

The plugin uses the Maven scope because Presto provides the classes from the SPI at runtime and thus the plugin should not include them in the plugin assembly.

All other dependencies are based on what the plugin needs for its own implementation. Plugins are loaded in a separate class loader to provide isolation and to allow plugins to use a different version of a library that Presto uses internally.

For an example pom.xml file, see the example HTTP connector in the presto-example-http directory in the root of the Presto source tree.

In order to add a custom plugin to a Presto installation, create a directory for that plugin in the Presto plugin directory and add all the necessary jars for the plugin to that directory. For example, for a plugin called my-functions, you would create a directory my-functions in the Presto plugin directory and add the relevant jars to that directory.

Plugins must be installed on all nodes in the Presto cluster (coordinator and workers).