Update python directories to better support setup.py

Signed-off-by: Jhon Honce <jhonce@redhat.com>

11 files changed, 751 insertions, 0 deletions

diff --git a/contrib/python/pypodman/lib/__init__.py b/contrib/python/pypodman/lib/__init__.py
new file mode 100644
index 000000000..5a8303668
--- /dev/null
+++ b/contrib/python/pypodman/lib/__init__.py
@@ -0,0 +1,11 @@
+"""Remote podman client support library."""
+from .action_base import AbstractActionBase
+from .config import PodmanArgumentParser
+from .report import Report, ReportColumn
+
+__all__ = [
+    'AbstractActionBase',
+    'PodmanArgumentParser',
+    'Report',
+    'ReportColumn',
+]
diff --git a/contrib/python/pypodman/lib/action_base.py b/contrib/python/pypodman/lib/action_base.py
new file mode 100644
index 000000000..ff2922262
--- /dev/null
+++ b/contrib/python/pypodman/lib/action_base.py
@@ -0,0 +1,84 @@
+"""Base class for all actions of remote client."""
+import abc
+from functools import lru_cache
+
+import podman
+
+
+class AbstractActionBase(abc.ABC):
+    """Base class for all actions of remote client."""
+
+    @classmethod
+    @abc.abstractmethod
+    def subparser(cls, parser):
+        """Define parser for this action.  Subclasses must implement.
+
+        API:
+        Use set_defaults() to set attributes "class_" and "method". These will
+        be invoked as class_(parsed_args).method()
+        """
+        parser.add_argument(
+            '--all',
+            action='store_true',
+            help=('list all items.'
+                  ' (default: no-op, included for compatibility.)'))
+        parser.add_argument(
+            '--no-trunc',
+            '--notruncate',
+            action='store_false',
+            dest='truncate',
+            default=True,
+            help='Display extended information. (default: False)')
+        parser.add_argument(
+            '--noheading',
+            action='store_false',
+            dest='heading',
+            default=True,
+            help=('Omit the table headings from the output.'
+                  ' (default: False)'))
+        parser.add_argument(
+            '--quiet',
+            action='store_true',
+            help='List only the IDs. (default: %(default)s)')
+
+    def __init__(self, args):
+        """Construct class."""
+        self._args = args
+
+    @property
+    def remote_uri(self):
+        """URI for remote side of connection."""
+        return self._args.remote_uri
+
+    @property
+    def local_uri(self):
+        """URI for local side of connection."""
+        return self._args.local_uri
+
+    @property
+    def identity_file(self):
+        """Key for authenication."""
+        return self._args.identity_file
+
+    @property
+    @lru_cache(maxsize=1)
+    def client(self):
+        """Podman remote client for communicating."""
+        if self._args.host is None:
+            return podman.Client(
+                uri=self.local_uri)
+        else:
+            return podman.Client(
+                uri=self.local_uri,
+                remote_uri=self.remote_uri,
+                identity_file=self.identity_file)
+
+    def __repr__(self):
+        """Compute the “official” string representation of object."""
+        return ("{}(local_uri='{}', remote_uri='{}',"
+                " identity_file='{}')").format(
+                    self.__class__,
+                    self.local_uri,
+                    self.remote_uri,
+                    self.identity_file,
+                )
diff --git a/contrib/python/pypodman/lib/actions/__init__.py b/contrib/python/pypodman/lib/actions/__init__.py
new file mode 100644
index 000000000..cdc58b6ab
--- /dev/null
+++ b/contrib/python/pypodman/lib/actions/__init__.py
@@ -0,0 +1,7 @@
+"""Module to export all the podman subcommands."""
+from .images_action import Images
+from .ps_action import Ps
+from .rm_action import Rm
+from .rmi_action import Rmi
+
+__all__ = ['Images', 'Ps', 'Rm', 'Rmi']
diff --git a/contrib/python/pypodman/lib/actions/images_action.py b/contrib/python/pypodman/lib/actions/images_action.py
new file mode 100644
index 000000000..f6a7497e5
--- /dev/null
+++ b/contrib/python/pypodman/lib/actions/images_action.py
@@ -0,0 +1,88 @@
+"""Remote client commands dealing with images."""
+import operator
+from collections import OrderedDict
+
+import humanize
+import podman
+
+from .. import AbstractActionBase, Report, ReportColumn
+
+
+class Images(AbstractActionBase):
+    """Class for Image manipulation."""
+
+    @classmethod
+    def subparser(cls, parent):
+        """Add Images commands to parent parser."""
+        parser = parent.add_parser('images', help='list images')
+        super().subparser(parser)
+        parser.add_argument(
+            '--sort',
+            choices=['created', 'id', 'repository', 'size', 'tag'],
+            default='created',
+            type=str.lower,
+            help=('Change sort ordered of displayed images.'
+                  ' (default: %(default)s)'))
+
+        group = parser.add_mutually_exclusive_group()
+        group.add_argument(
+            '--digests',
+            action='store_true',
+            help='Include digests with images. (default: %(default)s)')
+        parser.set_defaults(class_=cls, method='list')
+
+    def __init__(self, args):
+        """Construct Images class."""
+        super().__init__(args)
+
+        self.columns = OrderedDict({
+            'name':
+            ReportColumn('name', 'REPOSITORY', 40),
+            'tag':
+            ReportColumn('tag', 'TAG', 10),
+            'id':
+            ReportColumn('id', 'IMAGE ID', 12),
+            'created':
+            ReportColumn('created', 'CREATED', 12),
+            'size':
+            ReportColumn('size', 'SIZE', 8),
+            'repoDigests':
+            ReportColumn('repoDigests', 'DIGESTS', 35),
+        })
+
+    def list(self):
+        """List images."""
+        images = sorted(
+            self.client.images.list(),
+            key=operator.attrgetter(self._args.sort))
+        if len(images) == 0:
+            return 0
+
+        rows = list()
+        for image in images:
+            fields = dict(image)
+            fields.update({
+                'created':
+                humanize.naturaldate(podman.datetime_parse(image.created)),
+                'size':
+                humanize.naturalsize(int(image.size)),
+                'repoDigests':
+                ' '.join(image.repoDigests),
+            })
+
+            for r in image.repoTags:
+                name, tag = r.split(':', 1)
+                fields.update({
+                    'name': name,
+                    'tag': tag,
+                })
+                rows.append(fields)
+
+        if not self._args.digests:
+            del self.columns['repoDigests']
+
+        with Report(self.columns, heading=self._args.heading) as report:
+            report.layout(
+                rows, self.columns.keys(), truncate=self._args.truncate)
+            for row in rows:
+                report.row(**row)
diff --git a/contrib/python/pypodman/lib/actions/ps_action.py b/contrib/python/pypodman/lib/actions/ps_action.py
new file mode 100644
index 000000000..4bbec5578
--- /dev/null
+++ b/contrib/python/pypodman/lib/actions/ps_action.py
@@ -0,0 +1,76 @@
+"""Remote client commands dealing with containers."""
+import operator
+from collections import OrderedDict
+
+import humanize
+import podman
+
+from .. import AbstractActionBase, Report, ReportColumn
+
+
+class Ps(AbstractActionBase):
+    """Class for Container manipulation."""
+
+    @classmethod
+    def subparser(cls, parent):
+        """Add Images command to parent parser."""
+        parser = parent.add_parser('ps', help='list containers')
+        super().subparser(parser)
+        parser.add_argument(
+            '--sort',
+            choices=[
+                'createdat', 'id', 'image', 'names', 'runningfor', 'size',
+                'status'
+            ],
+            default='createdat',
+            type=str.lower,
+            help=('Change sort ordered of displayed containers.'
+                  ' (default: %(default)s)'))
+        parser.set_defaults(class_=cls, method='list')
+
+    def __init__(self, args):
+        """Construct Ps class."""
+        super().__init__(args)
+
+        self.columns = OrderedDict({
+            'id':
+            ReportColumn('id', 'CONTAINER ID', 14),
+            'image':
+            ReportColumn('image', 'IMAGE', 30),
+            'command':
+            ReportColumn('column', 'COMMAND', 20),
+            'createdat':
+            ReportColumn('createdat', 'CREATED', 12),
+            'status':
+            ReportColumn('status', 'STATUS', 10),
+            'ports':
+            ReportColumn('ports', 'PORTS', 28),
+            'names':
+            ReportColumn('names', 'NAMES', 18)
+        })
+
+    def list(self):
+        """List containers."""
+        # TODO: Verify sorting on dates and size
+        ctnrs = sorted(
+            self.client.containers.list(),
+            key=operator.attrgetter(self._args.sort))
+        if len(ctnrs) == 0:
+            return 0
+
+        rows = list()
+        for ctnr in ctnrs:
+            fields = dict(ctnr)
+            fields.update({
+                'command':
+                ' '.join(ctnr.command),
+                'createdat':
+                humanize.naturaldate(podman.datetime_parse(ctnr.createdat)),
+            })
+            rows.append(fields)
+
+        with Report(self.columns, heading=self._args.heading) as report:
+            report.layout(
+                rows, self.columns.keys(), truncate=self._args.truncate)
+            for row in rows:
+                report.row(**row)
diff --git a/contrib/python/pypodman/lib/actions/rm_action.py b/contrib/python/pypodman/lib/actions/rm_action.py
new file mode 100644
index 000000000..bd8950bd6
--- /dev/null
+++ b/contrib/python/pypodman/lib/actions/rm_action.py
@@ -0,0 +1,51 @@
+"""Remote client command for deleting containers."""
+import sys
+
+import podman
+
+from .. import AbstractActionBase
+
+
+class Rm(AbstractActionBase):
+    """Class for removing containers from storage."""
+
+    @classmethod
+    def subparser(cls, parent):
+        """Add Rm command to parent parser."""
+        parser = parent.add_parser('rm', help='delete container(s)')
+        parser.add_argument(
+            '-f',
+            '--force',
+            action='store_true',
+            help=('force delete of running container(s).'
+                  ' (default: %(default)s)'))
+        parser.add_argument(
+            'targets', nargs='*', help='container id(s) to delete')
+        parser.set_defaults(class_=cls, method='remove')
+
+    def __init__(self, args):
+        """Construct Rm class."""
+        super().__init__(args)
+        if len(args.targets) < 1:
+            raise ValueError('You must supply at least one container id'
+                             ' or name to be deleted.')
+
+    def remove(self):
+        """Remove container(s)."""
+        for id in self._args.targets:
+            try:
+                ctnr = self.client.containers.get(id)
+                ctnr.remove(self._args.force)
+                print(id)
+            except podman.ContainerNotFound as e:
+                sys.stdout.flush()
+                print(
+                    'Container {} not found.'.format(e.name),
+                    file=sys.stderr,
+                    flush=True)
+            except podman.ErrorOccurred as e:
+                sys.stdout.flush()
+                print(
+                    '{}'.format(e.reason).capitalize(),
+                    file=sys.stderr,
+                    flush=True)
diff --git a/contrib/python/pypodman/lib/actions/rmi_action.py b/contrib/python/pypodman/lib/actions/rmi_action.py
new file mode 100644
index 000000000..91f0deeaf
--- /dev/null
+++ b/contrib/python/pypodman/lib/actions/rmi_action.py
@@ -0,0 +1,50 @@
+"""Remote client command for deleting images."""
+import sys
+
+import podman
+
+from .. import AbstractActionBase
+
+
+class Rmi(AbstractActionBase):
+    """Clas for removing images from storage."""
+
+    @classmethod
+    def subparser(cls, parent):
+        """Add Rmi command to parent parser."""
+        parser = parent.add_parser('rmi', help='delete image(s)')
+        parser.add_argument(
+            '-f',
+            '--force',
+            action='store_true',
+            help=('force delete of image(s) and associated containers.'
+                  ' (default: %(default)s)'))
+        parser.add_argument('targets', nargs='*', help='image id(s) to delete')
+        parser.set_defaults(class_=cls, method='remove')
+
+    def __init__(self, args):
+        """Construct Rmi class."""
+        super().__init__(args)
+        if len(args.targets) < 1:
+            raise ValueError('You must supply at least one image id'
+                             ' or name to be deleted.')
+
+    def remove(self):
+        """Remove image(s)."""
+        for id in self._args.targets:
+            try:
+                img = self.client.images.get(id)
+                img.remove(self._args.force)
+                print(id)
+            except podman.ImageNotFound as e:
+                sys.stdout.flush()
+                print(
+                    'Image {} not found.'.format(e.name),
+                    file=sys.stderr,
+                    flush=True)
+            except podman.ErrorOccurred as e:
+                sys.stdout.flush()
+                print(
+                    '{}'.format(e.reason).capitalize(),
+                    file=sys.stderr,
+                    flush=True)
diff --git a/contrib/python/pypodman/lib/config.py b/contrib/python/pypodman/lib/config.py
new file mode 100644
index 000000000..e687697ef
--- /dev/null
+++ b/contrib/python/pypodman/lib/config.py
@@ -0,0 +1,212 @@
+import argparse
+import curses
+import getpass
+import inspect
+import logging
+import os
+import sys
+
+import pkg_resources
+
+import pytoml
+
+# TODO: setup.py and obtain __version__ from rpm.spec
+try:
+    __version__ = pkg_resources.get_distribution('pypodman').version
+except Exception:
+    __version__ = '0.0.0'
+
+
+class HelpFormatter(argparse.RawDescriptionHelpFormatter):
+    """Set help width to screen size."""
+
+    def __init__(self, *args, **kwargs):
+        """Construct HelpFormatter using screen width."""
+        if 'width' not in kwargs:
+            kwargs['width'] = 80
+            try:
+                height, width = curses.initscr().getmaxyx()
+                kwargs['width'] = width
+            finally:
+                curses.endwin()
+        super().__init__(*args, **kwargs)
+
+
+class PodmanArgumentParser(argparse.ArgumentParser):
+    """Default remote podman configuration."""
+
+    def __init__(self, **kwargs):
+        """Construct the parser."""
+        kwargs['add_help'] = True
+        kwargs['allow_abbrev'] = True
+        kwargs['description'] = __doc__
+        kwargs['formatter_class'] = HelpFormatter
+
+        super().__init__(**kwargs)
+
+    def initialize_parser(self):
+        """Initialize parser without causing recursion meltdown."""
+        self.add_argument(
+            '--version',
+            action='version',
+            version='%(prog)s v. ' + __version__)
+        self.add_argument(
+            '--log-level',
+            choices=['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'],
+            default='WARNING',
+            type=str.upper,
+            help='set logging level for events. (default: %(default)s)',
+        )
+        self.add_argument(
+            '--run-dir',
+            metavar='DIRECTORY',
+            help=('directory to place local socket bindings.'
+                  ' (default: XDG_RUNTIME_DIR/pypodman'))
+        self.add_argument(
+            '--user',
+            default=getpass.getuser(),
+            help='Authenicating user on remote host. (default: %(default)s)')
+        self.add_argument(
+            '--host', help='name of remote host. (default: None)')
+        self.add_argument(
+            '--remote-socket-path',
+            metavar='PATH',
+            help=('path of podman socket on remote host'
+                  ' (default: /run/podman/io.projectatomic.podman)'))
+        self.add_argument(
+            '--identity-file',
+            metavar='PATH',
+            help=('path to ssh identity file. (default: ~user/.ssh/id_dsa)'))
+        self.add_argument(
+            '--config-home',
+            metavar='DIRECTORY',
+            help=('home of configuration "pypodman.conf".'
+                  ' (default: XDG_CONFIG_HOME/pypodman'))
+
+        actions_parser = self.add_subparsers(
+            dest='subparser_name', help='actions')
+
+        # pull in plugin(s) code for each subcommand
+        for name, obj in inspect.getmembers(
+                sys.modules['lib.actions'],
+                lambda member: inspect.isclass(member)):
+            if hasattr(obj, 'subparser'):
+                try:
+                    obj.subparser(actions_parser)
+                except NameError as e:
+                    logging.critical(e)
+                    logging.warning(
+                        'See subparser configuration for Class "{}"'.format(
+                            name))
+                    sys.exit(3)
+
+    def parse_args(self, args=None, namespace=None):
+        """Parse command line arguments, backed by env var and config_file."""
+        self.initialize_parser()
+        cooked = super().parse_args(args, namespace)
+        return self.resolve_configuration(cooked)
+
+    def resolve_configuration(self, args):
+        """Find and fill in any arguments not passed on command line."""
+        args.xdg_runtime_dir = os.environ.get('XDG_RUNTIME_DIR', '/tmp')
+        args.xdg_config_home = os.environ.get('XDG_CONFIG_HOME',
+                                              os.path.expanduser('~/.config'))
+        args.xdg_config_dirs = os.environ.get('XDG_CONFIG_DIRS', '/etc/xdg')
+
+        # Configuration file(s) are optional,
+        #   required arguments may be provided elsewhere
+        config = {'default': {}}
+        dirs = args.xdg_config_dirs.split(':')
+        dirs.extend((args.xdg_config_home, args.config_home))
+        for dir_ in dirs:
+            if dir_ is None:
+                continue
+            try:
+                with open(os.path.join(dir_, 'pypodman/pypodman.conf'),
+                          'r') as stream:
+                    config.update(pytoml.load(stream))
+            except OSError:
+                pass
+
+        def reqattr(name, value):
+            if value:
+                setattr(args, name, value)
+                return value
+            self.error('Required argument "%s" is not configured.' % name)
+
+        reqattr(
+            'run_dir',
+            getattr(args, 'run_dir')
+            or os.environ.get('RUN_DIR')
+            or config['default'].get('run_dir')
+            or os.path.join(args.xdg_runtime_dir, 'pypodman')
+        )   # yapf: disable
+
+        setattr(
+            args,
+            'host',
+            getattr(args, 'host')
+            or os.environ.get('HOST')
+            or config['default'].get('host')
+        )   # yapf:disable
+
+        reqattr(
+            'user',
+            getattr(args, 'user')
+            or os.environ.get('USER')
+            or config['default'].get('user')
+            or getpass.getuser()
+        )   # yapf:disable
+
+        reqattr(
+            'remote_socket_path',
+            getattr(args, 'remote_socket_path')
+            or os.environ.get('REMOTE_SOCKET_PATH')
+            or config['default'].get('remote_socket_path')
+            or '/run/podman/io.projectatomic.podman'
+        )   # yapf:disable
+
+        reqattr(
+            'log_level',
+            getattr(args, 'log_level')
+            or os.environ.get('LOG_LEVEL')
+            or config['default'].get('log_level')
+            or logging.WARNING
+        )  # yapf:disable
+
+        setattr(
+            args,
+            'identity_file',
+            getattr(args, 'identity_file')
+            or os.environ.get('IDENTITY_FILE')
+            or config['default'].get('identity_file')
+            or os.path.expanduser('~{}/.ssh/id_dsa'.format(args.user))
+        )   # yapf:disable
+
+        if not os.path.isfile(args.identity_file):
+            args.identity_file = None
+
+        if args.host:
+            args.local_socket_path = os.path.join(args.run_dir,
+                                                  "podman.socket")
+        else:
+            args.local_socket_path = args.remote_socket_path
+
+        args.local_uri = "unix:{}".format(args.local_socket_path)
+        args.remote_uri = "ssh://{}@{}{}".format(args.user, args.host,
+                                                 args.remote_socket_path)
+        return args
+
+    def exit(self, status=0, message=None):
+        """Capture message and route to logger."""
+        if message:
+            log = logging.info if status == 0 else logging.error
+            log(message)
+        super().exit(status)
+
+    def error(self, message):
+        """Capture message and route to logger."""
+        logging.error('{}: {}'.format(self.prog, message))
+        logging.error("Try '{} --help' for more information.".format(
+            self.prog))
+        super().exit(2)
diff --git a/contrib/python/pypodman/lib/future_abstract.py b/contrib/python/pypodman/lib/future_abstract.py
new file mode 100644
index 000000000..75a1d42db
--- /dev/null
+++ b/contrib/python/pypodman/lib/future_abstract.py
@@ -0,0 +1,29 @@
+"""Utilities for with-statement contexts.  See PEP 343."""
+
+import abc
+
+import _collections_abc
+
+try:
+    from contextlib import AbstractContextManager
+except ImportError:
+    # Copied from python3.7 library as "backport"
+    class AbstractContextManager(abc.ABC):
+        """An abstract base class for context managers."""
+
+        def __enter__(self):
+            """Return `self` upon entering the runtime context."""
+            return self
+
+        @abc.abstractmethod
+        def __exit__(self, exc_type, exc_value, traceback):
+            """Raise any exception triggered within the runtime context."""
+            return None
+
+        @classmethod
+        def __subclasshook__(cls, C):
+            """Check whether subclass is considered a subclass of this ABC."""
+            if cls is AbstractContextManager:
+                return _collections_abc._check_methods(C, "__enter__",
+                                                       "__exit__")
+            return NotImplemented
diff --git a/contrib/python/pypodman/lib/pypodman.py b/contrib/python/pypodman/lib/pypodman.py
new file mode 100755
index 000000000..4bc71a9cc
--- /dev/null
+++ b/contrib/python/pypodman/lib/pypodman.py
@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+"""Remote podman client."""
+
+import logging
+import os
+import sys
+
+import lib.actions
+from lib import PodmanArgumentParser
+
+assert lib.actions  # silence pyflakes
+
+
+def main():
+    """Entry point."""
+    # Setup logging so we use stderr and can change logging level later
+    # Do it now before there is any chance of a default setup hardcoding crap.
+    log = logging.getLogger()
+    fmt = logging.Formatter('%(asctime)s | %(levelname)-8s | %(message)s',
+                            '%Y-%m-%d %H:%M:%S %Z')
+    stderr = logging.StreamHandler(stream=sys.stderr)
+    stderr.setFormatter(fmt)
+    log.addHandler(stderr)
+    log.setLevel(logging.WARNING)
+
+    parser = PodmanArgumentParser()
+    args = parser.parse_args()
+
+    log.setLevel(args.log_level)
+    logging.debug('Logging initialized at level {}'.format(
+        logging.getLevelName(logging.getLogger().getEffectiveLevel())))
+
+    def want_tb():
+        """Add traceback when logging events."""
+        return log.getEffectiveLevel() == logging.DEBUG
+
+    try:
+        if not os.path.exists(args.run_dir):
+            os.makedirs(args.run_dir)
+    except PermissionError as e:
+        logging.critical(e, exc_info=want_tb())
+        sys.exit(6)
+
+    # class_(args).method() are set by the sub-command's parser
+    returncode = None
+    try:
+        obj = args.class_(args)
+    except Exception as e:
+        logging.critical(repr(e), exc_info=want_tb())
+        logging.warning('See subparser "{}" configuration.'.format(
+            args.subparser_name))
+        sys.exit(5)
+
+    try:
+        returncode = getattr(obj, args.method)()
+    except AttributeError as e:
+        logging.critical(e, exc_info=want_tb())
+        logging.warning('See subparser "{}" configuration.'.format(
+            args.subparser_name))
+        returncode = 3
+    except KeyboardInterrupt:
+        pass
+    except (
+            ConnectionRefusedError,
+            ConnectionResetError,
+            TimeoutError,
+    ) as e:
+        logging.critical(e, exc_info=want_tb())
+        logging.info('Review connection arguments for correctness.')
+        returncode = 4
+
+    return 0 if returncode is None else returncode
+
+
+if __name__ == '__main__':
+    sys.exit(main())
diff --git a/contrib/python/pypodman/lib/report.py b/contrib/python/pypodman/lib/report.py
new file mode 100644
index 000000000..25fe2ae0d
--- /dev/null
+++ b/contrib/python/pypodman/lib/report.py
@@ -0,0 +1,67 @@
+"""Report Manager."""
+import sys
+from collections import namedtuple
+
+from .future_abstract import AbstractContextManager
+
+
+class ReportColumn(namedtuple('ReportColumn', 'key display width default')):
+    """Hold attributes of output column."""
+
+    __slots__ = ()
+
+    def __new__(cls, key, display, width, default=None):
+        """Add defaults for attributes."""
+        return super(ReportColumn, cls).__new__(cls, key, display, width,
+                                                default)
+
+
+class Report(AbstractContextManager):
+    """Report Manager."""
+
+    def __init__(self, columns, heading=True, epilog=None, file=sys.stdout):
+        """Construct Report.
+
+        columns is a mapping for named fields to column headings.
+        headers True prints headers on table.
+        epilog will be printed when the report context is closed.
+        """
+        self._columns = columns
+        self._file = file
+        self._heading = heading
+        self.epilog = epilog
+        self._format = None
+
+    def row(self, **fields):
+        """Print row for report."""
+        if self._heading:
+            hdrs = {k: v.display for (k, v) in self._columns.items()}
+            print(self._format.format(**hdrs), flush=True, file=self._file)
+            self._heading = False
+        fields = {k: str(v) for k, v in fields.items()}
+        print(self._format.format(**fields))
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        """Leave Report context and print epilog if provided."""
+        if self.epilog:
+            print(self.epilog, flush=True, file=self._file)
+
+    def layout(self, iterable, keys, truncate=True):
+        """Use data and headings build format for table to fit."""
+        format = []
+
+        for key in keys:
+            value = max(map(lambda x: len(str(x.get(key, ''))), iterable))
+            # print('key', key, 'value', value)
+
+            if truncate:
+                row = self._columns.get(
+                    key, ReportColumn(key, key.upper(), len(key)))
+                if value < row.width:
+                    step = row.width if value == 0 else value
+                    value = max(len(key), step)
+                elif value > row.width:
+                    value = row.width if row.width != 0 else value
+
+            format.append('{{{0}:{1}.{1}}}'.format(key, value))
+        self._format = ' '.join(format)