Snapcraft Ruby plugin for core20

README Ruby snap plugin

This is one way to build a snap for a Ruby app that:

* uses Ruby 3.3 with YJIT
* uses ZMQ/CZMQ, Sqlite3, libxml2, libmbedtls, libmysqlclient
* bundles custom fonts and wktohtmlpdf for PDF generation
* has a daemon (system service) which uses the 'network-bind' plug
* respects the env vars FOOBAR_APP (path to app) and FOOBAR_CONF (path to config file)
* has a separate, bundled web UI (unpacks webui-dist.tgz to /app/webui/dist inside the snap)
* builds the snap using an LXD container


HOW TO USE
==========
Put the ruby.py script into snap/plugins/ directory of your app.
Put the snapcraft.yml into the snap/ directory of your app.
Put the snapify.sh script into the root directory of your script.

The snapify.sh script packages the bundle (gems) into a tarball and doesn't update it unless necessary, which speeds up the snapping process.
Build artefacts are kept out of the final snap file to reduce size.

It works for our use case. Use at your own risk.

ruby.py

# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
#
# Copyright (C) 2021 Patrik Wenger <paddor@gmail.com>
#
# 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 ruby plugin is useful for ruby based parts.
It uses ruby-install to install Ruby and can use bundler to install
dependencies from a `Gemfile` found in the sources.

Additionally, this plugin uses the following plugin-specific keywords:
    - ruby-version:
      (string)
      The version of ruby you want this snap to run. (e.g. '3.0' or '2.7.2')
    - ruby-flavor:
      (string)
      Other flavors of ruby supported by ruby-install (e.g. 'jruby', ...)
    - ruby-gems:
      (list)
      A list of gems to install.
    - ruby-use-bundler
      (boolean)
      Use bundler to install gems from a Gemfile (defaults 'false').
    - ruby-prefix:
      (string)
      Prefix directory for installation (defaults '/usr').
    - ruby-shared:
      (boolean)
      Build ruby as a shared library (defaults 'false').
    - ruby-use-jemalloc:
      (boolean)
      Build ruby with libjemalloc (defaults 'false').
    - ruby-configure-options:
      (array of strings)
      Additional configure options to use when configuring ruby.
"""

import os
import re
import logging

from typing import Any, Dict, List, Set
from snapcraft.plugins.v2 import PluginV2


class PluginImpl(PluginV2):
    @classmethod
    def get_schema(cls) -> Dict[str, Any]:
        return {
            "$schema": "http://json-schema.org/draft-04/schema#",
            "type": "object",
            "additionalProperties": False,
            "properties": {
                "ruby-flavor": {
                    "type": "string",
                    "default": "ruby",
                },
                "ruby-version": {
                    "type": "string",
                    "default": "3.0",
                    "pattern": r"^\d+\.\d+(\.\d+)?$",
                },
                "ruby-use-bundler": {
                    "type": "boolean",
                    "default": False,
                },
                "ruby-prefix": {
                    "type": "string",
                    "default": "/usr",
                },
                "ruby-use-jemalloc": {
                    "type": "boolean",
                    "default": False,
                },
                "ruby-shared": {
                    "type": "boolean",
                    "default": False,
                },
                "ruby-configure-options": {
                    "type": "array",
                    "items": {"type": "string"},
                    "default": [],
                },
                "ruby-gems": {
                    "type": "array",
                    "items": {"type": "string"},
                    "default": [],
                },
            },
        }

    def get_build_snaps(self) -> Set[str]:
        return set()

    def get_build_packages(self) -> Set[str]:
        packages = {"curl"}

        if self.options.ruby_use_jemalloc:
            packages.add("libjemalloc-dev")

        return packages

    def get_build_environment(self) -> Dict[str, str]:
        env = {
            "PATH": f"${{SNAPCRAFT_PART_INSTALL}}{self.options.ruby_prefix}/bin:${{PATH}}",
        }

        if self.options.ruby_shared:
            # for finding ruby.so when running `gem` or `bundle`
            env["LD_LIBRARY_PATH"] = f"${{SNAPCRAFT_PART_INSTALL}}{self.options.ruby_prefix}/lib${{LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}}"

        return env

    def _configure_opts(self) -> List[str]:
        configure_opts = [
            "--without-baseruby",
            "--enable-load-relative",
            "--disable-install-doc",
        ] + self.options.ruby_configure_options

        if self.options.ruby_shared:
            configure_opts.append("--enable-shared")
        if self.options.ruby_use_jemalloc:
            configure_opts.append("--with-jemalloc")

        return configure_opts

    def get_build_commands(self) -> List[str]:
        # NOTE: To update ruby-install version, go to https://github.com/postmodern/ruby-install/tags
        ruby_install_version = '0.9.3'

        # NOTE: To update SHA256 checksum, run the following command (with updated version) and copy the output (one line) here:
        #   curl -L https://github.com/postmodern/ruby-install/archive/refs/tags/v0.9.3.tar.gz -o ruby-install.tar.gz && sha256sum --tag ruby-install.tar.gz
        ruby_install_checksum = 'SHA256 (ruby-install.tar.gz) = 3e920c9c770ce040cdf71cc64b809e861b613c570c6113ee61ab1d2885a16ab3'

        configure_opts = ' '.join(self._configure_opts())
        commands = ['uname -a', 'env']

        # NOTE: Download and verify ruby-install and use it to download, compile, and install Ruby
        commands.append(f"curl -L --proto '=https' --tlsv1.2 https://github.com/postmodern/ruby-install/archive/refs/tags/v{ruby_install_version}.tar.gz -o ruby-install.tar.gz")
        commands.append("echo 'Checksum of downloaded file:'")
        commands.append("sha256sum --tag ruby-install.tar.gz")
        commands.append("echo 'Checksum is correct if it matches:'")
        commands.append(f"echo '{ruby_install_checksum}'")
        commands.append(f"echo '{ruby_install_checksum}' | sha256sum --check --strict")
        commands.append("tar xfz ruby-install.tar.gz")
        commands.append(f"ruby-install-{ruby_install_version}/bin/ruby-install --src-dir ${{SNAPCRAFT_PART_SRC}} --install-dir ${{SNAPCRAFT_PART_INSTALL}}{self.options.ruby_prefix} --package-manager apt --jobs=${{SNAPCRAFT_PARALLEL_BUILD_COUNT}} {self.options.ruby_flavor}-{self.options.ruby_version} -- {configure_opts}")

        # NOTE: Update bundler and avoid conflicts/prompts about replacing bundler
        #       executables by removing them first.
        commands.append(f"rm -f ${{SNAPCRAFT_PART_INSTALL}}{self.options.ruby_prefix}/bin/{{bundle,bundler}}")
        commands.append("gem update --system")
        commands.append("gem install --env-shebang --no-document bundler")

        if self.options.ruby_use_bundler:
            commands.append("bundle")

        if self.options.ruby_gems:
            commands.append("gem install --env-shebang --no-document {}".format(' '.join(self.options.ruby_gems)))

        return commands

snapcraft.yaml

name: foobar
base: core20
version: '0.1.0'
summary: Foobar example snapcraft app
description: |
  Foobar example snapcraft app with daemon

grade: stable
confinement: strict

parts:
  ruby:
    plugin: ruby
    ruby-version: '3.3'
    ruby-shared: true
    build-packages:
      - zlib1g-dev
      - libssl-dev
      - rustc
    prime:
      - -usr/bin/bundler
      - -usr/bin/erb
      - -usr/bin/racc
      - -usr/bin/rake
      - -usr/bin/rbs
      - -usr/bin/rdoc
      - -usr/bin/ri
      - -usr/bin/typeprof
      - -usr/include
      - -usr/lib/ruby/gems/*/doc
      - -usr/share
      - -usr/share/man
      - -usr/usr/share/doc


  wkhtmltopdf:
    source: https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox_0.12.6-1.focal_amd64.deb
    source-type: deb
    plugin: dump
    stage-packages:
      - fontconfig
      - libjpeg8
      - libpng16-16
      - libx11-6
      - libxrender1
      - libssl1.1
      - xfonts-75dpi
      - xfonts-base
      - zlib1g
    override-stage: |
      snapcraftctl stage
      ln -sf ../local/bin/wkhtmltopdf $SNAPCRAFT_STAGE/usr/bin/wkhtmltopdf
    stage:
      # remove original config file
      - -etc/fonts/fonts.conf
    prime:
      - etc/fonts
#      - usr/bin/fc-list
      - usr/bin/wkhtmltopdf
      - usr/local/bin/wkhtmltopdf
      - usr/lib
      - usr/share/fonts/truetype
      - lib

  fontconfig:
    after:
      - wkhtmltopdf
    source: snap/local
    plugin: dump
    organize:
      # use our own config file
      fonts.conf: etc/fonts/


  app:
    source: .
    plugin: dump
    organize:
      bin: app/bin
      lib: app/lib
      conf: app/conf
      conf.rb.template: app/
      Gemfile*: app/
    stage:
      - app


  bundle:
    after:
      - ruby
      - app
    plugin: dump
    source: vendor_cache.tar.gz
    build-packages:
      - autoconf
      - automake
      - git
      - cmake
      - pkg-config
      - libczmq-dev
      - libsqlite3-dev
      - libmysqlclient-dev
      - libxml2-dev
      - python3
      - python3-pip
      - libmbedtls-dev
    stage-packages:
      - libsqlite3-dev
      - libmysqlclient-dev
      - libczmq-dev
      - libxml2-dev
      - libmbedtls-dev
    override-build: |
      env
      pip install conan
      command -v conan
      command -v bundle
      bundle version
      cd $SNAPCRAFT_STAGE/app

      bundle config set --local deployment true
      bundle config set --local path $SNAPCRAFT_PART_INSTALL/app/vendor/bundle
      bundle config set --local cache_path $SNAPCRAFT_PART_SRC
      bundle config set --local silence_root_warning true
      bundle config set --local jobs 1
      bundle env

      if [ -e $SNAPCRAFT_PART_SRC/../cache/bundle ]
      then
        mkdir -p $SNAPCRAFT_PART_INSTALL/app/vendor/
        cp -R $SNAPCRAFT_PART_SRC/../cache/bundle $SNAPCRAFT_PART_INSTALL/app/vendor/
      fi

      if bundle check
      then
        echo "Bundle is already installed."
      else
        echo "Installing bundle ..."
        bundle install --local

        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name '*.gem' -delete
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name '*.a' -delete
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name '*.o' -delete
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name 'gem_make.out' -delete
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name '*.h' -delete
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name '*.c' -delete
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name '*.md' -delete
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name 'test' -type d -print0 | xargs -0 rm -rf
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name 'spec' -type d -print0 | xargs -0 rm -rf
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name 'configure' -type f -delete
        find $SNAPCRAFT_PART_INSTALL/app/vendor/bundle -name '*.log' -type f -delete

        mkdir -p $SNAPCRAFT_PART_SRC/../cache
        cp -R $SNAPCRAFT_PART_INSTALL/app/vendor/bundle $SNAPCRAFT_PART_SRC/../cache/
      fi
    prime:
      - -usr/include
      - -usr/share
      - -usr/lib/x86_64-linux-gnu/*.a


  webui:
    source: webui-dist.tgz
    plugin: dump
    organize:
      '*': app/webui/dist/


apps:

  foobar:
    command: usr/bin/bundle exec $SNAP/app/bin/main
    plugs:
      - network-bind
    environment:
      BUNDLE_GEMFILE: $SNAP/app/Gemfile
      FOOBAR_APP: $SNAP/app
      FOOBAR_CONF: $SNAP_COMMON/conf.rb
      BUNDLE_PATH: $SNAP/app/vendor/bundle

  daemon:
    command: usr/bin/bundle exec $SNAP/app/bin/main start
    daemon: simple
    restart-condition: always
    restart-delay: 15s
    plugs:
      - network-bind
    environment:
      BUNDLE_GEMFILE: $SNAP/app/Gemfile
      RUBYOPT: --disable-did_you_mean
      FOOBAR_APP: $SNAP/app
      FOOBAR_CONF: $SNAP_COMMON/conf.rb
      BUNDLE_PATH: $SNAP/app/vendor/bundle
      XDG_DATA_HOME: $SNAP
      XDG_CONFIG_HOME: $SNAP
      FONTCONFIG_FILE: $SNAP/etc/fonts/fonts.conf

#  wkhtmltopdf:
#    command: usr/local/bin/wkhtmltopdf
#    environment:
#      XDG_DATA_HOME: $SNAP
#      XDG_CONFIG_HOME: $SNAP
#      FONTCONFIG_FILE: $SNAP/etc/fonts/fonts.conf
#
#  fc-list:
#    command: usr/bin/fc-list
#    environment:
#      XDG_DATA_HOME: $SNAP
#      XDG_CONFIG_HOME: $SNAP
#      FONTCONFIG_FILE: $SNAP/etc/fonts/fonts.conf

snapify.sh

#! /bin/sh -e


usage()
{
   cat << HEREDOC

   Usage: $0

   optional arguments:
     -h, --help       show this help message and exit
HEREDOC
}


while true; do
  case "$1" in
    -h | --help )
		usage; exit;;
    -- )
		shift; break ;;
    * )
		break ;;
  esac
done

BUNDLE_CACHE_ALL=1
BUNDLE_CACHE_ALL_PLATFORMS=1
BUNDLE_NO_INSTALL=1

export BUNDLE_CACHE_ALL
export BUNDLE_CACHE_ALL_PLATFORMS
export BUNDLE_NO_INSTALL

bundle check
bundle package

tar --sort=name --owner=root:0 --group=root:0 --mtime='UTC 2022-12-19' -c vendor/cache | gzip -n > vendor_cache_new.tar.gz

if diff -q vendor_cache.tar.gz vendor_cache_new.tar.gz
then
    echo "vendor/cache hasn't changed. Leaving vendor_cache.tar.gz as is."
    rm -f vendor_cache_new.tar.gz
else
    echo "vendor/cache has changed. Updating vendor_cache.tar.gz ..."
    mv vendor_cache_new.tar.gz vendor_cache.tar.gz
fi

snapcraft --use-lxd --debug