feat: do not create /bin/java symlink (#752)

* feat: override _get_java_link_commands

Maven and Ant plugin should not create /bin/java symlink

* doc: add rockcraft-specific docs for ant and maven

Ant and Maven plugins override build commands of craft-parts Ant and Maven plugins.

* feat: register plugin overrides

* test: add rockcraft plugin tests

- add smoke tests for maven and ant plugins.

* lint: reformat documentation

* test: add ant dependency

* test: fix ant plugin test

- drop unneeded property
- add ant plugin targets

* test: use symlink to java when running test

* test: replace modules files

- use package installation to ensure /usr/bin/java is present
- run jlink to replace modules

* test: drop modules part

- we have not merged JAVA_HOME fix yet, so do basic tests that plugin works

* test: rollback test changes

- we still have to create java symlink in rockcraft yaml
-  the test image is fixed for amd64, so its ok to hardcode path in task.yaml

* test: do not prune docker

* fix: add /usr/bin/java symlink

* doc: update documentation with /usr/bin/java symlink

* test: use /usr/bin/java in the test

* fix: fix typo in ln command

* lint: update formatting

* lint: apply ruff fixes

* doc: reuse common docs

Reuse common docs for maven and ant plugins.

* chore: rename part in ant test

ant test had part named 'maven-sample'.

* test: validate /bin/java

Validate that /bin/java is a valid command

* lint: reformat long lines

craft-parts ant plugin description has too long lines.

docs/reference/plugins.rst

@@ -11,13 +11,13 @@ Rockcraft.
    :maxdepth: 1
 
    /common/craft-parts/reference/plugins/dotnet_plugin
-   /common/craft-parts/reference/plugins/ant_plugin
+   plugins/ant_plugin
    /common/craft-parts/reference/plugins/autotools_plugin
    /common/craft-parts/reference/plugins/cmake_plugin
    /common/craft-parts/reference/plugins/dump_plugin
    /common/craft-parts/reference/plugins/go_plugin
    /common/craft-parts/reference/plugins/make_plugin
-   /common/craft-parts/reference/plugins/maven_plugin
+   plugins/maven_plugin
    /common/craft-parts/reference/plugins/meson_plugin
    /common/craft-parts/reference/plugins/nil_plugin
    /common/craft-parts/reference/plugins/npm_plugin

docs/reference/plugins/ant_plugin.rst

@@ -0,0 +1,64 @@
+.. _rockcraft_ant_plugin:
+
+Ant plugin
+==========
+
+The Ant plugin builds Java projects using the
+`Apache Ant <https://ant.apache.org/>`_ build tool.
+
+After a successful build, this plugin will:
+
+* Create ``jar/`` directory in ``$CRAFT_PART_INSTALL``.
+* Hard link the ``.jar`` files generated in ``$CRAFT_PART_BUILD`` to
+  ``$CRAFT_PART_INSTALL/jar``.
+* Find the ``java`` executable provided by the part and link it as
+  ``$CRAFT_PART_INSTALL/usr/bin/java`` if ``/usr/bin`` exists.
+
+
+Keywords
+--------
+
+In addition to the common :ref:`plugin <part-properties-plugin>` and
+:ref:`sources <part-properties-sources>` keywords, this plugin provides
+the following plugin-specific keywords:
+
+ant-build-targets
+~~~~~~~~~~~~~~~~~
+**Type:** list of strings
+
+The ant targets to build. These are directly passed to the ``ant`` command line.
+
+ant-build-file
+~~~~~~~~~~~~~~
+**Type:** str
+
+The name of the main XML build file. Defaults to ``build.xml``.
+
+ant-properties
+~~~~~~~~~~~~~~
+**Type:** dict of strings to strings
+
+A series of key: value pairs that are passed to ``ant`` as properties using the
+``-D{key}={value}`` notation.
+
+
+Environment variables
+---------------------
+
+This plugin reads the ``http_proxy`` and ``https_proxy`` variables from
+the environment to configure proxy access.
+
+Please refer to
+`Running Apache Ant <https://ant.apache.org/manual/running.html>`_ for
+a list of environment variables used by Ant.
+
+.. _rockcraft_ant-details-begin:
+
+.. include:: /common/craft-parts/reference/plugins/ant_plugin.rst
+   :start-after: .. _ant-details-begin:
+   :end-before: .. _ant-details-end:
+
+.. _rockcraft_ant-details-end:
+
+.. include:: /common/craft-parts/reference/plugins/ant_plugin.rst
+   :start-after: .. _ant-details-end:

docs/reference/plugins/maven_plugin.rst

@@ -0,0 +1,56 @@
+.. _rockcraft_maven_plugin:
+
+Maven plugin
+============
+
+The Maven plugin builds Java projects using the Maven build tool.
+
+After a successful build, this plugin will:
+
+* Create ``jar/`` directory in ``$CRAFT_PART_INSTALL``.
+* Hard link the ``.jar`` files generated in ``$CRAFT_PART_BUILD`` to
+  ``$CRAFT_PART_INSTALL/jar``.
+* Find the ``java`` executable provided by the part and link it as
+  ``$CRAFT_PART_INSTALL/usr/bin/java`` if ``/usr/bin`` exists.
+
+
+Keywords
+--------
+
+In addition to the common :ref:`plugin <part-properties-plugin>` and
+:ref:`sources <part-properties-sources>` keywords, this plugin
+provides the following plugin-specific keywords:
+
+maven-parameters
+~~~~~~~~~~~~~~~~
+**Type:** list of strings
+
+Used to add additional parameters to the ``mvn package`` command line.
+
+
+Environment variables
+---------------------
+
+This plugin reads the ``http_proxy`` and ``https_proxy`` variables
+from the environment to configure Maven proxy access. A
+comma-separated list of hosts that should not be accessed via proxy is
+read from the ``no_proxy`` environment variable. The plugin writes the
+proxy configuration in ``$CRAFT_PART_BUILD/.parts/.m2/settings.xml``.
+
+This plugin will set the ``JAVA_HOME`` environment variable to the
+path to the latest JDK found in the build environment.
+
+Please refer to
+`Configuring Apache Maven <https://maven.apache.org/configure.html>`_
+for a list of environment variables used to configure Maven.
+
+.. _rockcraft_maven-details-begin:
+
+.. include:: /common/craft-parts/reference/plugins/maven_plugin.rst
+   :start-after: .. _maven-details-begin:
+   :end-before: .. _maven-details-end:
+
+.. _rockcraft_maven-details-end:
+
+.. include:: /common/craft-parts/reference/plugins/maven_plugin.rst
+   :start-after: .. _maven-details-end:

rockcraft/plugins/ant_plugin.py

@@ -0,0 +1,40 @@
+# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
+#
+# Copyright 2024 Canonical Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""The Rockcraft Ant plugin."""
+import logging
+
+from craft_parts.plugins import ant_plugin
+from overrides import override  # type: ignore[reportUnknownVariableType]
+
+from .java_common import create_usr_bin_java
+
+logger = logging.getLogger(__name__)
+
+
+class AntPlugin(ant_plugin.AntPlugin):
+    """An AntPlugin plugin for Rockcraft.
+
+    This plugin extends Craft-parts' vanilla Ant plugin to properly
+    use and install the Java VM. Specifically:
+
+    - Do not link java executable to /bin/java
+    """
+
+    @override
+    def _get_java_link_commands(self) -> list[str]:
+        """Get the bash commands to provide /bin/java symlink."""
+        return create_usr_bin_java()

rockcraft/plugins/java_common.py

@@ -0,0 +1,30 @@
+# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
+#
+# Copyright 2024 Canonical Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""Common functionality for Java-based plugins.
+
+This module provides a function to create a /usr/bin/java symlink.
+"""
+
+
+def create_usr_bin_java() -> list[str]:
+    """Get the bash commands to create /usr/bin/java symlink."""
+    return [
+        '# Find the "java" executable and make a link to it in $CRAFT_PART_INSTALL/bin/java',
+        "java_bin=$(find ${CRAFT_PART_INSTALL} -name java -type f -executable)",
+        "test -d ${CRAFT_PART_INSTALL}/usr/bin && "
+        "(test -f ${CRAFT_PART_INSTALL}/usr/bin/java || "
+        "ln -s --relative $java_bin ${CRAFT_PART_INSTALL}/usr/bin/java)",
+    ]

rockcraft/plugins/maven_plugin.py

@@ -0,0 +1,40 @@
+# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
+#
+# Copyright 2024 Canonical Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""The Rockcraft Maven plugin."""
+import logging
+
+from craft_parts.plugins import maven_plugin
+from overrides import override  # type: ignore[reportUnknownVariableType]
+
+from .java_common import create_usr_bin_java
+
+logger = logging.getLogger(__name__)
+
+
+class MavenPlugin(maven_plugin.MavenPlugin):
+    """A MavenPlugin plugin for Rockcraft.
+
+    This plugin extends Craft-parts' vanilla Maven plugin to properly
+    use and install the Java VM. Specifically:
+
+    - Do not link java executable to /bin/java
+    """
+
+    @override
+    def _get_java_link_commands(self) -> list[str]:
+        """Get the bash commands to provide /usr/bin/java symlink."""
+        return create_usr_bin_java()

rockcraft/plugins/register.py

@@ -19,6 +19,8 @@
 import craft_parts
 from craft_parts.plugins.plugins import PluginType
 
+from .ant_plugin import AntPlugin
+from .maven_plugin import MavenPlugin
 from .poetry_plugin import PoetryPlugin
 from .python_plugin import PythonPlugin
 
@@ -30,4 +32,9 @@ def register() -> None:
 
 def get_plugins() -> dict[str, PluginType]:
     """Get a dict of Rockcraft-specific plugins."""
-    return {"poetry": PoetryPlugin, "python": PythonPlugin}
+    return {
+        "ant": AntPlugin,
+        "poetry": PoetryPlugin,
+        "python": PythonPlugin,
+        "maven": MavenPlugin,
+    }

tests/spread/rockcraft/plugin-ant/rockcraft.yaml

@@ -0,0 +1,22 @@
+name: plugin-ant
+base: bare
+build-base: [email protected]
+
+version: '0.1'
+summary: A rock that bundles an Ant project.
+description: A rock that bundles an Ant project.
+license: GPL-3.0
+platforms:
+  amd64:
+
+parts:
+  ant-sample:
+    plugin: ant
+    source: sample
+    ant-build-targets: [compile, jar]
+    stage-packages:
+     - openjdk-21-jre-headless_core
+     - base-files_base
+    build-packages:
+      - ant
+      - openjdk-21-jdk-headless

tests/spread/rockcraft/plugin-ant/sample/build.xml

@@ -0,0 +1,28 @@
+<project>
+
+    <property name="ant.build.javac.source" value="8"/>
+    <property name="ant.build.javac.target" value="8"/>
+
+    <target name="clean">
+        <delete dir="build"/>
+    </target>
+
+    <target name="compile">
+        <mkdir dir="build/classes"/>
+        <javac srcdir="src" destdir="build/classes"/>
+    </target>
+
+    <target name="jar">
+        <mkdir dir="build/jar"/>
+        <jar destfile="build/jar/HelloWorld.jar" basedir="build/classes">
+            <manifest>
+                <attribute name="Main-Class" value="sample.HelloWorld"/>
+            </manifest>
+        </jar>
+    </target>
+
+    <target name="run">
+        <java jar="build/jar/HelloWorld.jar" fork="true"/>
+    </target>
+
+</project>

tests/spread/rockcraft/plugin-ant/sample/src/sample/HelloWorld.java

@@ -0,0 +1,7 @@
+package sample;
+
+public class HelloWorld {
+    public static void main(String[] args) {
+        System.out.println("hello world");
+    }
+}

tests/spread/rockcraft/plugin-ant/task.yaml

@@ -0,0 +1,16 @@
+summary: Maven plugin tests
+execute: |
+  SCENARIO="plugin-ant"
+  ROCK_FILE="${SCENARIO}_0.1_amd64.rock"
+  IMAGE="${SCENARIO}:0.1"
+
+  # Build the rock & load it into docker
+  run_rockcraft pack
+  echo expecting ${ROCK_FILE}
+  test -f ${ROCK_FILE}
+  rockcraft.skopeo copy --insecure-policy  oci-archive:${ROCK_FILE} docker-daemon:${IMAGE}
+  rm ${ROCK_FILE}
+
+  # Run the packaged project
+  docker run --rm $IMAGE exec /usr/bin/java -jar /jar/HelloWorld.jar | MATCH "hello world"
+  docker run --rm $IMAGE exec /bin/java -jar /jar/HelloWorld.jar | MATCH "hello world"

tests/spread/rockcraft/plugin-maven/rockcraft.yaml

@@ -0,0 +1,22 @@
+name: plugin-maven
+base: bare
+build-base: [email protected]
+
+version: '0.1'
+summary: A rock that bundles a Maven project.
+description: A rock that bundles a Maven project.
+license: GPL-3.0
+platforms:
+  amd64:
+
+parts:
+  maven-sample:
+    plugin: maven
+    source: sample
+    maven-parameters: [ "-B" ]
+    stage-packages:
+     - openjdk-21-jre-headless_core
+     - base-files_base
+    build-packages:
+      - maven
+      - openjdk-21-jdk-headless