Add Alpine Linux support. (#535)

Add new module cc_apk_configure for creating Alpine /etc/apk/repositories file.
Modify cc_ca_certs, cc_ntp, cc_power_state_change, and cc_resolv_conf for Alpine.
Add Alpine template files for Chrony and Busybox NTP support.
Add Alpine template file for /etc/hosts.

1 files changed, 263 insertions, 0 deletions

diff --git a/cloudinit/config/cc_apk_configure.py b/cloudinit/config/cc_apk_configure.py
new file mode 100644
index 00000000..84d7a0b6
--- /dev/null
+++ b/cloudinit/config/cc_apk_configure.py
@@ -0,0 +1,263 @@
+# Copyright (c) 2020 Dermot Bradley
+#
+# Author: Dermot Bradley <dermot_bradley@yahoo.com>
+#
+# This file is part of cloud-init. See LICENSE file for license information.
+
+"""Apk Configure: Configures apk repositories file."""
+
+from textwrap import dedent
+
+from cloudinit import log as logging
+from cloudinit import temp_utils
+from cloudinit import templater
+from cloudinit import util
+from cloudinit.config.schema import (
+    get_schema_doc, validate_cloudconfig_schema)
+from cloudinit.settings import PER_INSTANCE
+
+LOG = logging.getLogger(__name__)
+
+
+# If no mirror is specified then use this one
+DEFAULT_MIRROR = "https://alpine.global.ssl.fastly.net/alpine"
+
+
+REPOSITORIES_TEMPLATE = """\
+## template:jinja
+#
+# Created by cloud-init
+#
+# This file is written on first boot of an instance
+#
+
+{{ alpine_baseurl }}/{{ alpine_version }}/main
+{% if community_enabled -%}
+{{ alpine_baseurl }}/{{ alpine_version }}/community
+{% endif -%}
+{% if testing_enabled -%}
+{% if alpine_version != 'edge' %}
+#
+# Testing - using with non-Edge installation may cause problems!
+#
+{% endif %}
+{{ alpine_baseurl }}/edge/testing
+{% endif %}
+{% if local_repo != '' %}
+
+#
+# Local repo
+#
+{{ local_repo }}/{{ alpine_version }}
+{% endif %}
+
+"""
+
+
+frequency = PER_INSTANCE
+distros = ['alpine']
+schema = {
+    'id': 'cc_apk_configure',
+    'name': 'APK Configure',
+    'title': 'Configure apk repositories file',
+    'description': dedent("""\
+        This module handles configuration of the /etc/apk/repositories file.
+
+        .. note::
+          To ensure that apk configuration is valid yaml, any strings
+          containing special characters, especially ``:`` should be quoted.
+    """),
+    'distros': distros,
+    'examples': [
+        dedent("""\
+        # Keep the existing /etc/apk/repositories file unaltered.
+        apk_repos:
+            preserve_repositories: true
+        """),
+        dedent("""\
+        # Create repositories file for Alpine v3.12 main and community
+        # using default mirror site.
+        apk_repos:
+            alpine_repo:
+                community_enabled: true
+                version: 'v3.12'
+        """),
+        dedent("""\
+        # Create repositories file for Alpine Edge main, community, and
+        # testing using a specified mirror site and also a local repo.
+        apk_repos:
+            alpine_repo:
+                base_url: 'https://some-alpine-mirror/alpine'
+                community_enabled: true
+                testing_enabled: true
+                version: 'edge'
+            local_repo_base_url: 'https://my-local-server/local-alpine'
+        """),
+    ],
+    'frequency': frequency,
+    'type': 'object',
+    'properties': {
+        'apk_repos': {
+            'type': 'object',
+            'properties': {
+                'preserve_repositories': {
+                    'type': 'boolean',
+                    'default': False,
+                    'description': dedent("""\
+                        By default, cloud-init will generate a new repositories
+                        file ``/etc/apk/repositories`` based on any valid
+                        configuration settings specified within a apk_repos
+                        section of cloud config. To disable this behavior and
+                        preserve the repositories file from the pristine image,
+                        set ``preserve_repositories`` to ``true``.
+
+                        The ``preserve_repositories`` option overrides
+                        all other config keys that would alter
+                        ``/etc/apk/repositories``.
+                    """)
+                },
+                'alpine_repo': {
+                    'type': ['object', 'null'],
+                    'properties': {
+                        'base_url': {
+                            'type': 'string',
+                            'default': DEFAULT_MIRROR,
+                            'description': dedent("""\
+                                The base URL of an Alpine repository, or
+                                mirror, to download official packages from.
+                                If not specified then it defaults to ``{}``
+                            """.format(DEFAULT_MIRROR))
+                        },
+                        'community_enabled': {
+                            'type': 'boolean',
+                            'default': False,
+                            'description': dedent("""\
+                                Whether to add the Community repo to the
+                                repositories file. By default the Community
+                                repo is not included.
+                            """)
+                        },
+                        'testing_enabled': {
+                            'type': 'boolean',
+                            'default': False,
+                            'description': dedent("""\
+                                Whether to add the Testing repo to the
+                                repositories file. By default the Testing
+                                repo is not included. It is only recommended
+                                to use the Testing repo on a machine running
+                                the ``Edge`` version of Alpine as packages
+                                installed from Testing may have dependancies
+                                that conflict with those in non-Edge Main or
+                                Community repos."
+                            """)
+                        },
+                        'version': {
+                            'type': 'string',
+                            'description': dedent("""\
+                                The Alpine version to use (e.g. ``v3.12`` or
+                                ``edge``)
+                            """)
+                        },
+                    },
+                    'required': ['version'],
+                    'minProperties': 1,
+                    'additionalProperties': False,
+                },
+                'local_repo_base_url': {
+                    'type': 'string',
+                    'description': dedent("""\
+                        The base URL of an Alpine repository containing
+                        unofficial packages
+                    """)
+                }
+            },
+            'required': [],
+            'minProperties': 1,  # Either preserve_repositories or alpine_repo
+            'additionalProperties': False,
+        }
+    }
+}
+
+__doc__ = get_schema_doc(schema)
+
+
+def handle(name, cfg, cloud, log, _args):
+    """
+    Call to handle apk_repos sections in cloud-config file.
+
+    @param name: The module name "apk-configure" from cloud.cfg
+    @param cfg: A nested dict containing the entire cloud config contents.
+    @param cloud: The CloudInit object in use.
+    @param log: Pre-initialized Python logger object to use for logging.
+    @param _args: Any module arguments from cloud.cfg
+    """
+
+    # If there is no "apk_repos" section in the configuration
+    # then do nothing.
+    apk_section = cfg.get('apk_repos')
+    if not apk_section:
+        LOG.debug(("Skipping module named %s,"
+                   " no 'apk_repos' section found"), name)
+        return
+
+    validate_cloudconfig_schema(cfg, schema)
+
+    # If "preserve_repositories" is explicitly set to True in
+    # the configuration do nothing.
+    if util.get_cfg_option_bool(apk_section, 'preserve_repositories', False):
+        LOG.debug(("Skipping module named %s,"
+                   " 'preserve_repositories' is set"), name)
+        return
+
+    # If there is no "alpine_repo" subsection of "apk_repos" present in the
+    # configuration then do nothing, as at least "version" is required to
+    # create valid repositories entries.
+    alpine_repo = apk_section.get('alpine_repo')
+    if not alpine_repo:
+        LOG.debug(("Skipping module named %s,"
+                   " no 'alpine_repo' configuration found"), name)
+        return
+
+    # If there is no "version" value present in configuration then do nothing.
+    alpine_version = alpine_repo.get('version')
+    if not alpine_version:
+        LOG.debug(("Skipping module named %s,"
+                   " 'version' not specified in alpine_repo"), name)
+        return
+
+    local_repo = apk_section.get('local_repo_base_url', '')
+
+    _write_repositories_file(alpine_repo, alpine_version, local_repo)
+
+
+def _write_repositories_file(alpine_repo, alpine_version, local_repo):
+    """
+    Write the /etc/apk/repositories file with the specified entries.
+
+    @param alpine_repo: A nested dict of the alpine_repo configuration.
+    @param alpine_version: A string of the Alpine version to use.
+    @param local_repo: A string containing the base URL of a local repo.
+    """
+
+    repo_file = '/etc/apk/repositories'
+
+    alpine_baseurl = alpine_repo.get('base_url', DEFAULT_MIRROR)
+
+    params = {'alpine_baseurl': alpine_baseurl,
+              'alpine_version': alpine_version,
+              'community_enabled': alpine_repo.get('community_enabled'),
+              'testing_enabled': alpine_repo.get('testing_enabled'),
+              'local_repo': local_repo}
+
+    tfile = temp_utils.mkstemp(prefix='template_name-', suffix=".tmpl")
+    template_fn = tfile[1]  # Filepath is second item in tuple
+    util.write_file(template_fn, content=REPOSITORIES_TEMPLATE)
+
+    LOG.debug('Generating Alpine repository configuration file: %s',
+              repo_file)
+    templater.render_to_file(template_fn, repo_file, params)
+    # Clean up temporary template
+    util.del_file(template_fn)
+
+
+# vi: ts=4 expandtab