cloud-init-dev team mailing list archive

[Scott Moser <ssmoser2+ubuntu@xxxxxxxxx>]

two small things, interested in your thoughts.


Diff comments:

> diff --git a/cloudinit/config/cc_snap.py b/cloudinit/config/cc_snap.py
> new file mode 100644
> index 0000000..edb21bb
> --- /dev/null
> +++ b/cloudinit/config/cc_snap.py
> @@ -0,0 +1,272 @@
> +# 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 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 of that list 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, 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 +            If 'side-loading' private/unpublished snaps on an instance, it is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 ommited 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,
> +                    'uniqueItems': True
> +                },
> +                '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 prepend_snap_commands(commands):
> +    """Ensure user-provided commands start with SNAP_CMD, warn otherwise.
> +
> +    Each command is either a list or string. Perform the following:
> +       - When the command is a list, pop the first element if it is None
> +       - When the command is a list, insert SNAP_CMD as the first element if
> +         not present.
> +       - When the command is a string containing a non-snap command, warn.
> +
> +    Support cut-n-paste snap command sets from public snappy documentation.
> +    Allow flexibility to provide non-snap environment/config setup if neeeded.
> +
> +    @commands: List of commands. Each command element is a list or string.
> +
> +    @return: List of 'fixed up' snap commands.
> +    @raise: TypeError on invalid config item type.
> +    """
> +    warnings = []
> +    errors = []
> +    fixed_commands = []
> +    for command in commands:
> +        if isinstance(command, list):
> +            if command[0] is None:  # Avoid warnings by specifying None
> +                command = command[1:]
> +            elif command[0] != SNAP_CMD:  # Automatically prepend SNAP_CMD
> +                command.insert(0, SNAP_CMD)
> +        elif isinstance(command, str):
> +            if not command.startswith('%s ' % SNAP_CMD):
> +                warnings.append(command)
> +        else:
> +            errors.append(str(command))
> +            continue
> +        fixed_commands.append(command)
> +
> +    if warnings:
> +        LOG.warning(
> +            'Non-snap commands in snap config:\n%s', '\n'.join(warnings))
> +    if errors:
> +        raise TypeError(
> +            'Invalid snap config.'
> +            ' These commands are not a string or list:\n' + '\n'.join(errors))
> +    return fixed_commands
> +
> +
> +def run_commands(commands):
> +    """Run the provided commands provided in snap:commands configuration.
> +
> +     Commands are aggregated,shellified and written to a temporary script file
> +     which is then executed.
> +
> +     @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_snap_commands(commands)
> +
> +    failed_cmds = []
> +    for command in fixed_snap_commands:
> +        shell = isinstance(command, str)
> +        try:
> +            util.subp(command, shell=shell, status_cb=sys.stderr.write)
> +        except util.ProcessExecutionError:
> +            failed_cmds.append(command)

will we get a log of the error anywhere here?
does it make sense to
  except util.ProcessExecutionError as e:
      failed_cmds.append(command, e)

even though 'e' will have the command that was executed in it. so you could just append the 'e'

> +    if failed_cmds:
> +        msg = 'Failed to run snap commands:\n{commands}'.format(
> +            commands=failed_cmds)
> +        util.logexc(LOG, msg)
> +        raise RuntimeError(msg)
> +
> +
> +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 as e:
> +        util.logexc(LOG, "Package update failed")
> +        raise
> +    try:
> +        cloud.distro.install_packages(['squashfuse'])
> +    except Exception as e:
> +        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
> diff --git a/tests/cloud_tests/testcases/modules/snap.yaml b/tests/cloud_tests/testcases/modules/snap.yaml
> new file mode 100644
> index 0000000..e520415
> --- /dev/null
> +++ b/tests/cloud_tests/testcases/modules/snap.yaml
> @@ -0,0 +1,21 @@
> +#
> +# Install snappy
> +#
> +required_features:
> +  - snap
> +cloud_config: |
> +  #cloud-config
> +  package_update: true
> +  snap:
> +    squashfuse_in_container: true
> +    commands:
> +      - snap install hello-world
> +collect_scripts:
> +  snaplist: |
> +    #!/bin/bash
> +    snap list
> +  instance-data.json: |
> +    #!/bin/sh
> +    cat /run/cloud-init/instance-data.json

collection (and validation of) /run/cloud-init/instance-data.json
should be done generically.  it is not at all specific to snappy.

tests/cloud_tests/testcases/base.py
has collection of result.json we can move this there.

> +
> +# vi: ts=4 expandtab


-- 
https://code.launchpad.net/~chad.smith/cloud-init/+git/cloud-init/+merge/338366
Your team cloud-init commiters is requested to review the proposed merge of ~chad.smith/cloud-init:feature/snap-module into cloud-init:master.