gcr.io/paketo-buildpacks/apache-tomcat

The Paketo Buildpack for Apache Tomcat is a Cloud Native Buildpack that contributes Apache Tomcat and Process Types for WARs.

Behavior

This buildpack will participate if all of the following conditions are met

• $BP_JAVA_APP_SERVER is tomcat or if $BP_JAVA_APP_SERVER is unset or empty and this is the first buildpack to provide a Java application server.
• <APPLICATION_ROOT>/WEB-INF exists
• Main-Class is NOT defined in the manifest

The buildpack will do the following:

• Requests that a JRE be installed
• Contribute a Tomcat instance to $CATALINA_HOME
• Contribute a Tomcat instance to $CATALINA_BASE
  • Contribute context.xml, logging.properties, server.xml, and web.xml to conf/
  • Contribute Access Logging Support, Lifecycle Support, and Logging Support
  • Contribute external configuration if available
• Contributes tomcat, task, and web process types

Tiny Stack

When this buildpack runs on the Tiny stack, which has no shell, the following notes apply:

• As there is no shell, the catalina.sh script cannot be used to start Tomcat
• The Tomcat Buildpack will generate a start command directly. It does not support all the functionality in catalina.sh.
• Some configuration options such as bin/setenv.sh and setting CATALINA_* environment variables, will not be available.
• Tomcat will be run with umask set to 0022 instead of the catalina.shprovided default of 0027

Configuration

External Configuration Package

The artifacts that the repository provides must be in TAR format and must follow the Tomcat archive structure:

<CATALINA_BASE>
 conf
     context.xml
     server.xml
     web.xml
     ...

Environment Property Source

When the Environment Property Source is configured, configuration for Tomcats configuration files can be loaded from environment variables. To use this feature, the name of the environment variable must match the name of the property.

Bindings

The buildpack optionally accepts the following bindings:

Type: dependency-mapping

Providing Additional JARs to Tomcat

Buildpacks can contribute JARs to the CLASSPATH of Tomcat by appending a path to BPI_TOMCAT_ADDITIONAL_JARS.

func (s) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
	// Copy dependency into the layer
	file := filepath.Join(layer.Path, filepath.Base(s.Dependency.URI))

	layer, err := s.LayerContributor.Contribute(layer, func(artifact *os.File) (libcnb.Layer, error) {
		if err := sherpa.CopyFile(artifact, file); err != nil {
			return libcnb.Layer{}, fmt.Errorf("unable to copy artifact to %s\n%w", file, err)
		}
		return layer, nil
	})

	additionalJars := []string{file}
  // Add dependency to BPI_TOMCAT_ADDITIONAL_JARS
	layer.LaunchEnvironment.Append("BPI_TOMCAT_ADDITIONAL_JARS", ":", strings.Join(additionalJars, ":"))
	return layer, nil
}

License

This buildpack is released under version 2.0 of the Apache License.