feat: add go init profile and go-extension (#631)

* WIP go-extension

* fix linting

* Fix linting

* fix linting

* Fix linting

* typo fix

* Rename init profile go to go-extension

* Add working dir

* Replace go-extention base directory /go with /app

* Run github action

* Preparing init profile

* fix pebble link

* Revert spread.yaml

This reverts commit 7030c28.

* build-base not needed in the test anymore

* Reorder and improve code

* Fix formatting

* Add 24.04 base to the go extension as default

* Revert spread.yaml file

This reverts commit 956e2ce.

* Add base 24.04 by default instead of 22.04

* Add asser for docs_url in exception

* Add extra platforms for flask, django and go

* Rerun actions

* Launch actions

* launch actions

* Update rockcraft/commands/init.py

apply suggested fix to docs

Co-authored-by: Tiago Nobrega <[email protected]>

* Update rockcraft/commands/init.py

Co-authored-by: Tiago Nobrega <[email protected]>

* Update rockcraft/extensions/go.py

Co-authored-by: Tiago Nobrega <[email protected]>

* doc_url -> doc_slug

* Improve _get_nested, as "." is a valid character in a yaml name

* correct type to dict

* remove pdb

* remove support for 22.04 in go

* comment non amd64 platforms in extensions

* Add comment for platforms in extensions

* add missing type annotations

* Apply suggestions from code review

Co-authored-by: Alex Lowe <[email protected]>

---------

Co-authored-by: Tiago Nobrega <[email protected]>
Co-authored-by: Alex Lowe <[email protected]>

rockcraft/commands/init.py

@@ -98,8 +98,13 @@ class InitCommand(AppCommand):
                     most important story about it. Keep it under 100 words though,
                     we live in tweetspace and your description wants to look good in the
                     container registries out there.
-                platforms: # the platforms this rock should be built on and run on
+                # the platforms this rock should be built on and run on.
+                # you can check your architecture with `dpkg --print-architecture`
+                platforms:
                     amd64:
+                    # arm64:
+                    # ppc64el:
+                    # s390x:
 
                 # to ensure the flask-framework extension works properly, your Flask application
                 # should have an `app.py` file with an `app` object as the WSGI entrypoint.
@@ -171,8 +176,13 @@ class InitCommand(AppCommand):
                     most important story about it. Keep it under 100 words though,
                     we live in tweetspace and your description wants to look good in the
                     container registries out there.
-                platforms: # The platforms this rock should be built on and run on
+                # the platforms this rock should be built on and run on.
+                # you can check your architecture with `dpkg --print-architecture`
+                platforms:
                     amd64:
+                    # arm64:
+                    # ppc64el:
+                    # s390x:
 
                 # to ensure the django-framework extension functions properly, your Django project
                 # should have a structure similar to the following with ./{snake_name}/{snake_name}/wsgi.py
@@ -201,6 +211,71 @@ class InitCommand(AppCommand):
             """
             )
         ),
+        "go-framework": _InitProfile(
+            rockcraft_yaml=textwrap.dedent(
+                """\
+                name: {name}
+                # see {versioned_url}/explanation/bases/
+                # for more information about bases and using 'bare' bases for chiselled rocks
+                base: bare # as an alternative, a ubuntu base can be used
+                build-base: [email protected] # build-base is required when the base is bare
+                version: '0.1' # just for humans. Semantic versioning is recommended
+                summary: A summary of your Go application # 79 char long summary
+                description: |
+                    This is {name}'s description. You have a paragraph or two to tell the
+                    most important story about it. Keep it under 100 words though,
+                    we live in tweetspace and your description wants to look good in the
+                    container registries out there.
+                # the platforms this rock should be built on and run on.
+                # you can check your architecture with `dpkg --print-architecture`
+                platforms:
+                    amd64:
+                    # arm64:
+                    # ppc64el:
+                    # s390x:
+
+                # to ensure the go-framework extension functions properly, your Go project
+                # should have a go.mod file. Check the parts section for the selection of
+                # the default binary.
+                # see {versioned_url}/reference/extensions/go-framework
+                # for more information.
+                # +-- {snake_name}
+                # |   |-- go.mod
+                # |   |-- migrate.sh
+
+                extensions:
+                    - go-framework
+
+                # uncomment the sections you need and adjust according to your requirements.
+                # parts:
+
+                #   go-framework/install-app:
+                #    # select a specific Go version. Otherwise the current stable one will be used.
+                #    build-snaps:
+                #    - go/1.22/stable
+                #    organize:
+                #    # if the main package is in the base directory and the rockcraft name
+                #    # attribute is equal to the go module name, the name of the server will
+                #    # be selected correctly, otherwise you can adjust it.
+                #    # the file in /usr/local/bin/ with the name of the rockcraft project will be
+                #    # the binary to run your server.
+                #    # you can also include here other binary files to be included in the rock.
+                #      bin/otherbinary: usr/local/bin/projectname
+
+                #   go-framework/assets:
+                #     stage:
+                #       # by default, only the files in templates/ and static/
+                #       # are copied into the image. You can modify the list below to override
+                #       # the default list and include or exclude specific files/directories
+                #       # in your project.
+                #       # note: Prefix each entry with "app/" followed by the local path.
+                #       - app/templates
+                #       - app/static
+                #       - app/otherdirectory
+                #       - app/otherfile
+            """
+            )
+        ),
     }
     _DEFAULT_PROFILE = "simple"
 

rockcraft/extensions/__init__.py

@@ -17,6 +17,7 @@
 """Extension processor and related utilities."""
 
 from ._utils import apply_extensions
+from .go import GoFramework
 from .gunicorn import DjangoFramework, FlaskFramework
 from .registry import get_extension_class, get_extension_names, register, unregister
 
@@ -30,3 +31,4 @@
 
 register("django-framework", DjangoFramework)
 register("flask-framework", FlaskFramework)
+register("go-framework", GoFramework)

rockcraft/extensions/go.py

@@ -0,0 +1,214 @@
+# -*- 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/>.
+
+"""An extension for Go based applications."""
+
+import os
+import re
+from typing import Any, Dict, Tuple
+
+from overrides import override
+
+from ..errors import ExtensionError
+from .extension import Extension
+
+
+class GoFramework(Extension):
+    """An extension class for Go applications."""
+
+    @staticmethod
+    @override
+    def get_supported_bases() -> Tuple[str, ...]:
+        """Return supported bases."""
+        return "bare", "[email protected]"
+
+    @staticmethod
+    @override
+    def is_experimental(base: str | None) -> bool:
+        """Check if the extension is in an experimental state."""
+        return True
+
+    @override
+    def get_root_snippet(self) -> dict[str, Any]:
+        """Return the root snippet to apply."""
+        self._check_project()
+
+        snippet: Dict[str, Any] = {
+            "run_user": "_daemon_",
+            "services": {
+                "go": {
+                    "override": "replace",
+                    "startup": "enabled",
+                    "command": self.project_name,
+                    "user": "_daemon_",
+                    "working-dir": "/app",
+                },
+            },
+        }
+
+        snippet["parts"] = {
+            # This is needed in case there is no assets part, as the working directory is /app
+            "go-framework/base-layout": {
+                "plugin": "nil",
+                "override-build": "mkdir -p ${CRAFT_PART_INSTALL}/app",
+            },
+            "go-framework/install-app": self._get_install_app_part(),
+            "go-framework/runtime": {
+                "plugin": "nil",
+                "stage-packages": ["ca-certificates_data"],
+            },
+        }
+
+        assets_part = self._get_install_assets_part()
+        if assets_part:
+            snippet["parts"]["go-framework/assets"] = assets_part
+
+        return snippet
+
+    @override
+    def get_parts_snippet(self) -> dict[str, Any]:
+        """Return the parts to add to parts."""
+        return {}
+
+    @override
+    def get_part_snippet(self) -> dict[str, Any]:
+        """Return the part snippet to apply to existing parts."""
+        return {}
+
+    @property
+    def project_name(self) -> str:
+        """Return the normalized name of the rockcraft project."""
+        return self.yaml_data["name"]
+
+    def _check_project(self) -> None:
+        """Check go.mod file exist in project."""
+        if not (self.project_root / "go.mod").exists():
+            raise ExtensionError(
+                "missing go.mod file",
+                doc_slug="/reference/extensions/go-framework",
+                logpath_report=False,
+            )
+
+    def _get_install_app_part(self) -> Dict[str, Any]:
+        """Generate install-app part with the Go plugin."""
+        install_app = self._get_nested(
+            self.yaml_data, ["parts", "go-framework/install-app"]
+        )
+
+        build_environment = install_app.get("build-environment", [])
+        if self.yaml_data["base"] == "bare":
+            for env_var in build_environment:
+                if "CGO_ENABLED" in env_var:
+                    break
+            else:
+                build_environment = [{"CGO_ENABLED": "0"}]
+
+        organize = install_app.get("organize", {})
+        binary_path = f"usr/local/bin/{self.project_name}"
+        for path in organize.values():
+            if path == binary_path:
+                break
+        else:
+            if not self._get_nested(self.yaml_data, ["services", "go", "command"]):
+                organize[f"bin/{self.project_name}"] = binary_path
+
+        install_app_part = {
+            "plugin": "go",
+            "source": ".",
+            "organize": organize,
+        }
+
+        if not self._check_go_overriden():
+            build_snaps = install_app.get("build-snaps", [])
+            build_snaps.append("go")
+            install_app_part["build-snaps"] = build_snaps
+
+        install_app_part["stage"] = list(organize.values())
+        if build_environment:
+            install_app_part["build-environment"] = build_environment
+
+        return install_app_part
+
+    def _check_go_overriden(self) -> bool:
+        """Check if the user overrode the go snap or package for the build step."""
+        install_app = self._get_nested(
+            self.yaml_data, ["parts", "go-framework/install-app"]
+        )
+        build_snaps = install_app.get("build-snaps", [])
+        if build_snaps:
+            for snap in build_snaps:
+                if snap.startswith("go"):
+                    return True
+        build_packages = install_app.get("build-packages", [])
+        if build_packages:
+            for package in build_packages:
+                if package in ["gccgo-go", "golang-go"]:
+                    return True
+        return False
+
+    def _get_install_assets_part(self) -> Dict[str, Any] | None:
+        """Generate assets-stage part for extra assets in the project."""
+        # if stage is not in exclude mode, use it to generate organize
+        if (
+            self._assets_stage
+            and self._assets_stage[0]
+            and self._assets_stage[0][0] != "-"
+        ):
+            renaming_map = {
+                os.path.relpath(file, "app"): file for file in self._assets_stage
+            }
+        else:
+            return None
+
+        return {
+            "plugin": "dump",
+            "source": ".",
+            "organize": renaming_map,
+            "stage": self._assets_stage,
+        }
+
+    @property
+    def _assets_stage(self) -> list[str]:
+        """Return the assets stage list for the Go project."""
+        user_stage = self._get_nested(
+            self.yaml_data, ["parts", "go-framework/assets"]
+        ).get("stage", [])
+
+        if not all(re.match("-? *app/", p) for p in user_stage):
+            raise ExtensionError(
+                "go-framework extension requires the 'stage' entry in the "
+                "go-framework/assets part to start with app",
+                doc_slug="/reference/extensions/go-framework",
+                logpath_report=False,
+            )
+        if not user_stage:
+            user_stage = [
+                f"app/{f}"
+                for f in (
+                    "migrate",
+                    "migrate.sh",
+                    "static",
+                    "templates",
+                )
+                if (self.project_root / f).exists()
+            ]
+        return user_stage
+
+    def _get_nested(self, obj: dict, paths: list[str]) -> dict:
+        """Get a nested object using a path (a list of keys)."""
+        for key in paths:
+            obj = obj.get(key, {})
+        return obj

tests/spread/rockcraft/extension-go/README.md

@@ -0,0 +1 @@
+test

tests/spread/rockcraft/extension-go/go.mod

@@ -0,0 +1,3 @@
+module github.com/canonical/NAME
+
+go 1.22.4

tests/spread/rockcraft/extension-go/main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func hello(w http.ResponseWriter, req *http.Request) {
+	fmt.Fprintf(w, "ok")
+}
+
+func main() {
+	http.HandleFunc("/", hello)
+	http.ListenAndServe(":8000", nil)
+}

tests/spread/rockcraft/extension-go/task.yaml

@@ -0,0 +1,46 @@
+summary: go extension test
+environment:
+  SCENARIO/bare: bare
+  SCENARIO/base_2404: ubuntu-24.04
+  ROCKCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS: "true"
+
+execute: |
+  NAME="go-${SCENARIO//./-}"
+  ROCK_FILE="${NAME}_0.1_amd64.rock"
+  IMAGE="${NAME}:0.1"
+
+  run_rockcraft init --name "${NAME}" --profile go-framework
+  sed -i "s/^name: .*/name: ${NAME}/g" rockcraft.yaml
+  sed -i "s/^base: .*/base: ${SCENARIO//-/@}/g" rockcraft.yaml
+  if [ "${SCENARIO}" != "bare" ]; then
+    sed -i "s/^build-base: .*/build-base: ${SCENARIO//-/@}/g" rockcraft.yaml
+  fi
+  sed -i "s/NAME/${NAME}/g" go.mod
+
+  run_rockcraft pack
+
+  test -f "${ROCK_FILE}"
+  test ! -d work
+
+  # Ensure docker does not have this container image
+  docker rmi --force "${IMAGE}"
+  # Install container
+  sudo rockcraft.skopeo --insecure-policy copy "oci-archive:${ROCK_FILE}" "docker-daemon:${IMAGE}"
+  # Ensure container exists
+  docker images "${IMAGE}" | MATCH "${NAME}"
+
+  # ensure container doesn't exist
+  docker rm -f "${NAME}-container"
+
+  # test the default go service
+  docker run --name "${NAME}-container" -d -p 8137:8000 "${IMAGE}"
+  retry -n 5 --wait 2 curl localhost:8137
+  [ "$(curl -sSf localhost:8137)" == "ok" ]
+
+restore: |
+  NAME="go-${SCENARIO//./-}"
+  sed -i "s/${NAME}/NAME/g" go.mod
+  docker stop "${NAME}-container"
+  docker rm "${NAME}-container"
+  rm -f "*.rock" rockcraft.yaml
+  docker system prune -a -f