File Content: cc_snap.py # Copyright (C) 2018 Canonical Ltd. # # This file is part of cloud-init. See LICENSE file for license information. """Snap: Install, configure and manage snapd and snap packages.""" import sys from textwrap import dedent from cloudinit import log as logging from cloudinit.config.schema import ( get_schema_doc, validate_cloudconfig_schema) from cloudinit.settings import PER_INSTANCE from cloudinit.subp import prepend_base_command from cloudinit import util distros = ['ubuntu'] frequency = PER_INSTANCE LOG = logging.getLogger(__name__) schema = { 'id': 'cc_snap', 'name': 'Snap', 'title': 'Install, configure and manage snapd and snap packages', 'description': dedent("""\ This module provides a simple configuration namespace in cloud-init to both setup snapd and install snaps. .. note:: Both ``assertions`` and ``commands`` values can be either a dictionary or a list. If these configs are provided as a dictionary, the keys are only used to order the execution of the assertions or commands and the dictionary is merged with any vendor-data snap configuration provided. If a list is provided by the user instead of a dict, any vendor-data snap configuration is ignored. The ``assertions`` configuration option is a dictionary or list of properly-signed snap assertions which will run before any snap ``commands``. They will be added to snapd's assertion database by invoking ``snap ack <aggregate_assertion_file>``. Snap ``commands`` is a dictionary or list of individual snap commands to run on the target system. These commands can be used to create snap users, install snaps and provide snap configuration. .. note:: If 'side-loading' private/unpublished snaps on an instance, it is best to create a snap seed directory and seed.yaml manifest in **/var/lib/snapd/seed/** which snapd automatically installs on startup. **Development only**: The ``squashfuse_in_container`` boolean can be set true to install squashfuse package when in a container to enable snap installs. Default is false. """), 'distros': distros, 'examples': [dedent("""\ snap: assertions: 00: | signed_assertion_blob_here 02: | signed_assertion_blob_here commands: 00: snap create-user --sudoer --known <snap-user>@mydomain.com 01: snap install canonical-livepatch 02: canonical-livepatch enable <AUTH_TOKEN> """), dedent("""\ # LXC-based containers require squashfuse before snaps can be installed snap: commands: 00: apt-get install squashfuse -y 11: snap install emoj """), dedent("""\ # Convenience: the snap command can be omitted when specifying commands # as a list and 'snap' will automatically be prepended. # The following commands are equivalent: snap: commands: 00: ['install', 'vlc'] 01: ['snap', 'install', 'vlc'] 02: snap install vlc 03: 'snap install vlc' """)], 'frequency': PER_INSTANCE, 'type': 'object', 'properties': { 'snap': { 'type': 'object', 'properties': { 'assertions': { 'type': ['object', 'array'], # Array of strings or dict 'items': {'type': 'string'}, 'additionalItems': False, # Reject items non-string 'minItems': 1, 'minProperties': 1, 'uniqueItems': True }, 'commands': { 'type': ['object', 'array'], # Array of strings or dict 'items': { 'oneOf': [ {'type': 'array', 'items': {'type': 'string'}}, {'type': 'string'}] }, 'additionalItems': False, # Reject non-string & non-list 'minItems': 1, 'minProperties': 1, }, 'squashfuse_in_container': { 'type': 'boolean' } }, 'additionalProperties': False, # Reject keys not in schema 'required': [], 'minProperties': 1 } } } # TODO schema for 'assertions' and 'commands' are too permissive at the moment. # Once python-jsonschema supports schema draft 6 add support for arbitrary # object keys with 'patternProperties' constraint to validate string values. __doc__ = get_schema_doc(schema) # Supplement python help() SNAP_CMD = "snap" ASSERTIONS_FILE = "/var/lib/cloud/instance/snapd.assertions" def add_assertions(assertions): """Import list of assertions. Import assertions by concatenating each assertion into a string separated by a '\n'. Write this string to a instance file and then invoke `snap ack /path/to/file` and check for errors. If snap exits 0, then all assertions are imported. """ if not assertions: return LOG.debug('Importing user-provided snap assertions') if isinstance(assertions, dict): assertions = assertions.values() elif not isinstance(assertions, list): raise TypeError( 'assertion parameter was not a list or dict: {assertions}'.format( assertions=assertions)) snap_cmd = [SNAP_CMD, 'ack'] combined = "\n".join(assertions) for asrt in assertions: LOG.debug('Snap acking: %s', asrt.split('\n')[0:2]) util.write_file(ASSERTIONS_FILE, combined.encode('utf-8')) util.subp(snap_cmd + [ASSERTIONS_FILE], capture=True) def run_commands(commands): """Run the provided commands provided in snap:commands configuration. Commands are run individually. Any errors are collected and reported after attempting all commands. @param commands: A list or dict containing commands to run. Keys of a dict will be used to order the commands provided as dict values. """ if not commands: return LOG.debug('Running user-provided snap commands') if isinstance(commands, dict): # Sort commands based on dictionary key commands = [v for _, v in sorted(commands.items())] elif not isinstance(commands, list): raise TypeError( 'commands parameter was not a list or dict: {commands}'.format( commands=commands)) fixed_snap_commands = prepend_base_command('snap', commands) cmd_failures = [] for command in fixed_snap_commands: shell = isinstance(command, str) try: util.subp(command, shell=shell, status_cb=sys.stderr.write) except util.ProcessExecutionError as e: cmd_failures.append(str(e)) if cmd_failures: msg = 'Failures running snap commands:\n{cmd_failures}'.format( cmd_failures=cmd_failures) util.logexc(LOG, msg) raise RuntimeError(msg) # RELEASE_BLOCKER: Once LP: #1628289 is released on xenial, drop this function. def maybe_install_squashfuse(cloud): """Install squashfuse if we are in a container.""" if not util.is_container(): return try: cloud.distro.update_package_sources() except Exception: util.logexc(LOG, "Package update failed") raise try: cloud.distro.install_packages(['squashfuse']) except Exception: util.logexc(LOG, "Failed to install squashfuse") raise def handle(name, cfg, cloud, log, args): cfgin = cfg.get('snap', {}) if not cfgin: LOG.debug(("Skipping module named %s," " no 'snap' key in configuration"), name) return validate_cloudconfig_schema(cfg, schema) if util.is_true(cfgin.get('squashfuse_in_container', False)): maybe_install_squashfuse(cloud) add_assertions(cfgin.get('assertions', [])) run_commands(cfgin.get('commands', [])) # vi: ts=4 expandtab Submit