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.

2 files changed, 169 insertions, 3 deletions

diff --git a/cloudinit/distros/__init__.py b/cloudinit/distros/__init__.py
index c7163e1c..effb4276 100755
--- a/cloudinit/distros/__init__.py
+++ b/cloudinit/distros/__init__.py
@@ -40,12 +40,13 @@ from .networking import LinuxNetworking
 ALL_DISTROS = 'all'
 
 OSFAMILIES = {
+    'alpine': ['alpine'],
+    'arch': ['arch'],
     'debian': ['debian', 'ubuntu'],
-    'redhat': ['amazon', 'centos', 'fedora', 'rhel'],
-    'gentoo': ['gentoo'],
     'freebsd': ['freebsd'],
+    'gentoo': ['gentoo'],
+    'redhat': ['amazon', 'centos', 'fedora', 'rhel'],
     'suse': ['opensuse', 'sles'],
-    'arch': ['arch'],
 }
 
 LOG = logging.getLogger(__name__)
diff --git a/cloudinit/distros/alpine.py b/cloudinit/distros/alpine.py
new file mode 100644
index 00000000..e42443fc
--- /dev/null
+++ b/cloudinit/distros/alpine.py
@@ -0,0 +1,165 @@
+# Copyright (C) 2016 Matt Dainty
+# Copyright (C) 2020 Dermot Bradley
+#
+# Author: Matt Dainty <matt@bodgit-n-scarper.com>
+# Author: Dermot Bradley <dermot_bradley@yahoo.com>
+#
+# This file is part of cloud-init. See LICENSE file for license information.
+
+from cloudinit import distros
+from cloudinit import helpers
+from cloudinit import log as logging
+from cloudinit import subp
+from cloudinit import util
+
+from cloudinit.distros.parsers.hostname import HostnameConf
+
+from cloudinit.settings import PER_INSTANCE
+
+LOG = logging.getLogger(__name__)
+
+NETWORK_FILE_HEADER = """\
+# This file is generated from information provided by the datasource. Changes
+# to it will not persist across an instance reboot. To disable cloud-init's
+# network configuration capabilities, write a file
+# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
+# network: {config: disabled}
+
+"""
+
+
+class Distro(distros.Distro):
+    init_cmd = ['rc-service']  # init scripts
+    locale_conf_fn = "/etc/profile.d/locale.sh"
+    network_conf_fn = "/etc/network/interfaces"
+    renderer_configs = {
+        "eni": {"eni_path": network_conf_fn,
+                "eni_header": NETWORK_FILE_HEADER}
+    }
+
+    def __init__(self, name, cfg, paths):
+        distros.Distro.__init__(self, name, cfg, paths)
+        # This will be used to restrict certain
+        # calls from repeatly happening (when they
+        # should only happen say once per instance...)
+        self._runner = helpers.Runners(paths)
+        self.default_locale = 'C.UTF-8'
+        self.osfamily = 'alpine'
+        cfg['ssh_svcname'] = 'sshd'
+
+    def get_locale(self):
+        """The default locale for Alpine Linux is different than
+           cloud-init's DataSource default.
+        """
+        return self.default_locale
+
+    def apply_locale(self, locale, out_fn=None):
+        # Alpine has limited locale support due to musl library limitations
+
+        if not locale:
+            locale = self.default_locale
+        if not out_fn:
+            out_fn = self.locale_conf_fn
+
+        lines = [
+            "#",
+            "# This file is created by cloud-init once per new instance boot",
+            "#",
+            "export CHARSET=UTF-8",
+            "export LANG=%s" % locale,
+            "export LC_COLLATE=C",
+            "",
+        ]
+        util.write_file(out_fn, "\n".join(lines), 0o644)
+
+    def install_packages(self, pkglist):
+        self.update_package_sources()
+        self.package_command('add', pkgs=pkglist)
+
+    def _write_network_config(self, netconfig):
+        return self._supported_write_network_config(netconfig)
+
+    def _bring_up_interfaces(self, device_names):
+        use_all = False
+        for d in device_names:
+            if d == 'all':
+                use_all = True
+        if use_all:
+            return distros.Distro._bring_up_interface(self, '-a')
+        else:
+            return distros.Distro._bring_up_interfaces(self, device_names)
+
+    def _write_hostname(self, your_hostname, out_fn):
+        conf = None
+        try:
+            # Try to update the previous one
+            # so lets see if we can read it first.
+            conf = self._read_hostname_conf(out_fn)
+        except IOError:
+            pass
+        if not conf:
+            conf = HostnameConf('')
+        conf.set_hostname(your_hostname)
+        util.write_file(out_fn, str(conf), 0o644)
+
+    def _read_system_hostname(self):
+        sys_hostname = self._read_hostname(self.hostname_conf_fn)
+        return (self.hostname_conf_fn, sys_hostname)
+
+    def _read_hostname_conf(self, filename):
+        conf = HostnameConf(util.load_file(filename))
+        conf.parse()
+        return conf
+
+    def _read_hostname(self, filename, default=None):
+        hostname = None
+        try:
+            conf = self._read_hostname_conf(filename)
+            hostname = conf.hostname
+        except IOError:
+            pass
+        if not hostname:
+            return default
+        return hostname
+
+    def _get_localhost_ip(self):
+        return "127.0.1.1"
+
+    def set_timezone(self, tz):
+        distros.set_etc_timezone(tz=tz, tz_file=self._find_tz_file(tz))
+
+    def package_command(self, command, args=None, pkgs=None):
+        if pkgs is None:
+            pkgs = []
+
+        cmd = ['apk']
+        # Redirect output
+        cmd.append("--quiet")
+
+        if args and isinstance(args, str):
+            cmd.append(args)
+        elif args and isinstance(args, list):
+            cmd.extend(args)
+
+        if command:
+            cmd.append(command)
+
+        pkglist = util.expand_package_list('%s-%s', pkgs)
+        cmd.extend(pkglist)
+
+        # Allow the output of this to flow outwards (ie not be captured)
+        subp.subp(cmd, capture=False)
+
+    def update_package_sources(self):
+        self._runner.run("update-sources", self.package_command,
+                         ["update"], freq=PER_INSTANCE)
+
+    @property
+    def preferred_ntp_clients(self):
+        """Allow distro to determine the preferred ntp client list"""
+        if not self._preferred_ntp_clients:
+            self._preferred_ntp_clients = ['chrony', 'ntp']
+
+        return self._preferred_ntp_clients
+
+# vi: ts=4 expandtab