Merge ~jugmac00/lpci:add-golang-plugin into lpci:main

[Jürgen Gmach]

Add Golang plugin

[Jürgen Gmach (jugmac00)]

I was not sure whether it makes sense to enter any invalid value to the version field, as the validator converts everything to string and in case that was not a valid golang version, the user gets a proper message in the error log.

I could add e.g. a value of `[1.18]` to the version field, which is not valid, and which would result in lpcraft trying to install `golang-[1.18]`...

[Colin Watson (cjwatson)]

review: Approve

[Jürgen Gmach (jugmac00)]

Thanks for the review!

diff --git a/NEWS.rst b/NEWS.rst
index 924486c..3c3b4d6 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -2,6 +2,11 @@
 Version history
 ===============
 
+0.0.21 (unreleased)
+===================
+
+- Add Golang plugin.
+
 0.0.20 (2022-07-15)
 ===================
 
diff --git a/lpcraft/plugin/tests/test_plugins.py b/lpcraft/plugin/tests/test_plugins.py
index 5b28fd7..3a9a357 100644
--- a/lpcraft/plugin/tests/test_plugins.py
+++ b/lpcraft/plugin/tests/test_plugins.py
@@ -10,7 +10,7 @@ from unittest.mock import ANY, Mock, call, patch
 
 from craft_providers.lxd import launch
 from fixtures import TempDir
-from pydantic import StrictStr, validator
+from pydantic import StrictStr, ValidationError, validator
 
 import lpcraft.config
 from lpcraft.commands.tests import CommandBaseTestCase
@@ -961,3 +961,122 @@ class TestPlugins(CommandBaseTestCase):
         )
 
         self.assertEqual(0, result.exit_code)
+
+    @patch("lpcraft.commands.run.get_provider")
+    @patch("lpcraft.commands.run.get_host_architecture", return_value="amd64")
+    def test_golang_plugin(
+        self, mock_get_host_architecture, mock_get_provider
+    ):
+        launcher = Mock(spec=launch)
+        provider = makeLXDProvider(lxd_launcher=launcher)
+        mock_get_provider.return_value = provider
+        execute_run = launcher.return_value.execute_run
+        execute_run.return_value = subprocess.CompletedProcess([], 0)
+        config = dedent(
+            """
+            pipeline:
+                - build
+
+            jobs:
+                build:
+                    plugin: golang
+                    golang-version: "1.17"
+                    series: focal
+                    architectures: amd64
+                    packages: [file, git]
+                    run: go build -x examples/go-top.go
+            """
+        )
+        Path(".launchpad.yaml").write_text(config)
+
+        self.run_command("run")
+        self.assertEqual(
+            [
+                call(
+                    ["apt", "update"],
+                    cwd=PosixPath("/root/lpcraft/project"),
+                    env={},
+                    stdout=ANY,
+                    stderr=ANY,
+                ),
+                call(
+                    ["apt", "install", "-y", "golang-1.17", "file", "git"],
+                    cwd=PosixPath("/root/lpcraft/project"),
+                    env={},
+                    stdout=ANY,
+                    stderr=ANY,
+                ),
+                call(
+                    [
+                        "bash",
+                        "--noprofile",
+                        "--norc",
+                        "-ec",
+                        "\nexport PATH=/usr/lib/go-1.17/bin/:$PATH\ngo build -x examples/go-top.go",  # noqa: E501
+                    ],
+                    cwd=PosixPath("/root/lpcraft/project"),
+                    env={},
+                    stdout=ANY,
+                    stderr=ANY,
+                ),
+            ],
+            execute_run.call_args_list,
+        )
+
+    @patch("lpcraft.commands.run.get_provider")
+    @patch("lpcraft.commands.run.get_host_architecture", return_value="amd64")
+    def test_golang_plugin_with_illegal_version(
+        self, mock_get_host_architecture, mock_get_provider
+    ):
+        launcher = Mock(spec=launch)
+        provider = makeLXDProvider(lxd_launcher=launcher)
+        mock_get_provider.return_value = provider
+        execute_run = launcher.return_value.execute_run
+        execute_run.return_value = subprocess.CompletedProcess([], 0)
+        # we do not allow floats as e.g. `1.20` is a problematic value in YAML
+        config = dedent(
+            """
+            pipeline:
+                - build
+            jobs:
+                build:
+                    plugin: golang
+                    golang-version: 1.18
+                    series: focal
+                    architectures: amd64
+                    packages: [file, git]
+                    run: go build -x examples/go-top.go
+            """
+        )
+        Path(".launchpad.yaml").write_text(config)
+
+        result = self.run_command("run")
+
+        self.assertEqual(1, result.exit_code)
+
+        [error] = result.errors
+        self.assertIn("str type expected", str(error))
+
+    def test_load_golang_plugin_configuration_with_invalid_version(self):
+        config = dedent(
+            """
+            pipeline:
+                - build
+            jobs:
+                build:
+                    plugin: golang
+                    golang-version: 1.18
+                    series: focal
+                    architectures: amd64
+                    packages: [file, git]
+                    run: go build -x examples/go-top.go
+            """
+        )
+        config_path = Path(".launchpad.yaml")
+        config_path.write_text(config)
+
+        self.assertRaises(
+            ValidationError,
+            lpcraft.config.Config.load,
+            config_path,
+        )
diff --git a/lpcraft/plugins/plugins.py b/lpcraft/plugins/plugins.py
index 833c461..d4464ee 100644
--- a/lpcraft/plugins/plugins.py
+++ b/lpcraft/plugins/plugins.py
@@ -8,6 +8,7 @@ __all__ = [
     "PyProjectBuildPlugin",
     "MiniCondaPlugin",
     "CondaBuildPlugin",
+    "GolangPlugin",
 ]
 
 import textwrap
@@ -399,3 +400,54 @@ class CondaBuildPlugin(MiniCondaPlugin):
             {build_command}{conda_channels}{configs} {self.build_target}
             {run_command}"""
         )
+
+
+@register(name="golang")
+class GolangPlugin(BasePlugin):
+    """Installs the required `golang` version.
+
+    Usage:
+        In `.launchpad.yaml`, create the following structure. Please note that
+        the `golang-version` has to be a string.
+
+        .. code-block:: yaml
+
+            pipeline:
+                - build
+
+            jobs:
+                build:
+                    plugin: golang
+                    golang-version: "1.17"
+                    series: focal
+                    architectures: amd64
+                    packages: [file, git]
+                    run: go build -x examples/go-top.go
+
+    Please note that the requested golang package needs to be available
+    either in the standard repository or in a repository specified in
+    `package-repositories`.
+    """
+
+    class Config(BaseConfig):
+        golang_version: StrictStr
+
+    INTERPOLATES_RUN_COMMAND = True
+
+    def get_plugin_config(self) -> "GolangPlugin.Config":
+        return cast(GolangPlugin.Config, self.config.plugin_config)
+
+    @hookimpl  # type: ignore
+    def lpcraft_install_packages(self) -> list[str]:
+        version = self.get_plugin_config().golang_version
+        return [f"golang-{version}"]
+
+    @hookimpl  # type: ignore
+    def lpcraft_execute_run(self) -> str:
+        version = self.get_plugin_config().golang_version
+        run_command = self.config.run or ""
+        return textwrap.dedent(
+            f"""
+            export PATH=/usr/lib/go-{version}/bin/:$PATH
+            {run_command}"""
+        )
diff --git a/setup.cfg b/setup.cfg
index 620de17..76d03ce 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = lpcraft
-version = 0.0.20
+version = 0.0.21.dev0
 description = Runner for Launchpad CI jobs
 long_description = file: README.rst
 long_description_content_type = text/x-rst