Refactor libpod python varlink bindings

- More pythonic
- Leverage context managers to help with socket leaks
- Add system unittest's
- Add image unittest's
- Add container unittest's
- Add models for system, containers and images, and their collections
- Add helper functions for datetime parsing/formatting
- GetInfo() implemented
- Add support for setuptools
- Update documentation
- Support for Python 3.4-3.6

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

Closes: #748
Approved by: baude

7 files changed, 645 insertions, 0 deletions

diff --git a/contrib/python/podman/__init__.py b/contrib/python/podman/__init__.py
new file mode 100644
index 000000000..5a0356311
--- /dev/null
+++ b/contrib/python/podman/__init__.py
@@ -0,0 +1,22 @@
+"""A client for communicating with a Podman server."""
+import pkg_resources
+
+from .client import Client
+from .libs import datetime_format, datetime_parse
+from .libs.errors import (ContainerNotFound, ErrorOccurred, ImageNotFound,
+                          RuntimeError)
+
+try:
+    __version__ = pkg_resources.get_distribution('podman').version
+except Exception:
+    __version__ = '0.0.0'
+
+__all__ = [
+    'Client',
+    'ContainerNotFound',
+    'datetime_format',
+    'datetime_parse',
+    'ErrorOccurred',
+    'ImageNotFound',
+    'RuntimeError',
+]
diff --git a/contrib/python/podman/client.py b/contrib/python/podman/client.py
new file mode 100644
index 000000000..8a1acdd9b
--- /dev/null
+++ b/contrib/python/podman/client.py
@@ -0,0 +1,81 @@
+"""A client for communicating with a Podman varlink service."""
+import contextlib
+import functools
+
+from varlink import Client as VarlinkClient
+from varlink import VarlinkError
+
+from .libs import cached_property
+from .libs.containers import Containers
+from .libs.errors import error_factory
+from .libs.images import Images
+from .libs.system import System
+
+
+class Client(object):
+    """A client for communicating with a Podman varlink service.
+
+    Example:
+
+        >>> import podman
+        >>> c = podman.Client()
+        >>> c.system.versions
+    """
+
+    # TODO: Port to contextlib.AbstractContextManager once
+    #   Python >=3.6 required
+
+    def __init__(self,
+                 uri='unix:/run/podman/io.projectatomic.podman',
+                 interface='io.projectatomic.podman'):
+        """Construct a podman varlink Client.
+
+        uri from default systemd unit file.
+        interface from io.projectatomic.podman.varlink, do not change unless
+            you are a varlink guru.
+        """
+        self._podman = None
+
+        @contextlib.contextmanager
+        def _podman(uri, interface):
+            """Context manager for API children to access varlink."""
+            client = VarlinkClient(address=uri)
+            try:
+                iface = client.open(interface)
+                yield iface
+            except VarlinkError as e:
+                raise error_factory(e) from e
+            finally:
+                if hasattr(client, 'close'):
+                    client.close()
+                iface.close()
+
+        self._client = functools.partial(_podman, uri, interface)
+
+        # Quick validation of connection data provided
+        if not System(self._client).ping():
+            raise ValueError('Failed varlink connection "{}/{}"'.format(
+                uri, interface))
+
+    def __enter__(self):
+        """Return `self` upon entering the runtime context."""
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        """Raise any exception triggered within the runtime context."""
+        return None
+
+    @cached_property
+    def system(self):
+        """Manage system model for podman."""
+        return System(self._client)
+
+    @cached_property
+    def images(self):
+        """Manage images model for libpod."""
+        return Images(self._client)
+
+    @cached_property
+    def containers(self):
+        """Manage containers model for libpod."""
+        return Containers(self._client)
diff --git a/contrib/python/podman/libs/__init__.py b/contrib/python/podman/libs/__init__.py
new file mode 100644
index 000000000..ab8fb94a8
--- /dev/null
+++ b/contrib/python/podman/libs/__init__.py
@@ -0,0 +1,96 @@
+"""Support files for podman API implementation."""
+import datetime
+import re
+import threading
+
+__all__ = [
+    'cached_property',
+    'datetime_parse',
+    'datetime_format',
+]
+
+
+class cached_property(object):
+    """cached_property() - computed once per instance, cached as attribute.
+
+    Maybe this will make a future version of python.
+    """
+
+    def __init__(self, func):
+        """Construct context manager."""
+        self.func = func
+        self.__doc__ = func.__doc__
+        self.lock = threading.RLock()
+
+    def __get__(self, instance, cls=None):
+        """Retrieve previous value, or call func()."""
+        if instance is None:
+            return self
+
+        attrname = self.func.__name__
+        try:
+            cache = instance.__dict__
+        except AttributeError:  # objects with __slots__ have no __dict__
+            msg = ("No '__dict__' attribute on {}"
+                   " instance to cache {} property.").format(
+                       repr(type(instance).__name__), repr(attrname))
+            raise TypeError(msg) from None
+
+        with self.lock:
+            # check if another thread filled cache while we awaited lock
+            if attrname not in cache:
+                cache[attrname] = self.func(instance)
+        return cache[attrname]
+
+
+def datetime_parse(string):
+    """Convert timestamp to datetime.
+
+    Because date/time parsing in python is still pedantically stupid,
+    we rip the input string apart throwing out the stop characters etc;
+    then rebuild a string strptime() can parse. Igit!
+
+    - Python >3.7 will address colons in the UTC offset.
+    - There is no ETA on microseconds > 6 digits.
+    - And giving an offset and timezone name...
+
+    # match: 2018-05-08T14:12:53.797795191-07:00
+    # match: 2018-05-08T18:24:52.753227-07:00
+    # match: 2018-05-08 14:12:53.797795191 -0700 MST
+    # match: 2018-05-09T10:45:57.576002  (python isoformat())
+
+    Some people, when confronted with a problem, think “I know,
+    I'll use regular expressions.”  Now they have two problems.
+      -- Jamie Zawinski
+    """
+    ts = re.compile(r'^(\d+)-(\d+)-(\d+)'
+                    r'[ T]?(\d+):(\d+):(\d+).(\d+)'
+                    r' *([-+][\d:]{4,5})? *')
+
+    x = ts.match(string)
+    if x is None:
+        raise ValueError('Unable to parse {}'.format(string))
+
+    # converting everything to int() not worth the readablity hit
+    igit_proof = '{}T{}.{}{}'.format(
+        '-'.join(x.group(1, 2, 3)),
+        ':'.join(x.group(4, 5, 6)),
+        x.group(7)[0:6],
+        x.group(8).replace(':', '') if x.group(8) else '',
+    )
+
+    format = '%Y-%m-%dT%H:%M:%S.%f'
+    if x.group(8):
+        format += '%z'
+    return datetime.datetime.strptime(igit_proof, format)
+
+
+def datetime_format(dt):
+    """Format datetime in consistent style."""
+    if isinstance(dt, str):
+        return datetime_parse(dt).isoformat()
+    elif isinstance(dt, datetime.datetime):
+        return dt.isoformat()
+    else:
+        raise ValueError('Unable to format {}. Type {} not supported.'.format(
+            dt, type(dt)))
diff --git a/contrib/python/podman/libs/containers.py b/contrib/python/podman/libs/containers.py
new file mode 100644
index 000000000..cbbef23b1
--- /dev/null
+++ b/contrib/python/podman/libs/containers.py
@@ -0,0 +1,211 @@
+"""Models for manipulating containers and storage."""
+import collections
+import functools
+import json
+import signal
+
+
+class Container(collections.UserDict):
+    """Model for a container."""
+
+    def __init__(self, client, id, data):
+        """Construct Container Model."""
+        super(Container, self).__init__(data)
+
+        self._client = client
+        self._id = id
+
+        self._refresh(data)
+        assert self._id == self.data['id'],\
+            'Requested container id({}) does not match store id({})'.format(
+                self._id, self.id
+            )
+
+    def __getitem__(self, key):
+        """Get items from parent dict + apply aliases."""
+        if key == 'running':
+            key = 'containerrunning'
+        return super().__getitem__(key)
+
+    def _refresh(self, data):
+        super().update(data)
+        for k, v in data.items():
+            setattr(self, k, v)
+        setattr(self, 'running', data['containerrunning'])
+
+    def refresh(self):
+        """Refresh status fields for this container."""
+        ctnr = Containers(self._client).get(self.id)
+        self._refresh(ctnr)
+
+    def attach(self, detach_key=None, no_stdin=False, sig_proxy=True):
+        """Attach to running container."""
+        with self._client() as podman:
+            # TODO: streaming and port magic occur, need arguements
+            podman.AttachToContainer()
+
+    def processes(self):
+        """Show processes running in container."""
+        with self._client() as podman:
+            results = podman.ListContainerProcesses(self.id)
+        for p in results['container']:
+            yield p
+
+    def changes(self):
+        """Retrieve container changes."""
+        with self._client() as podman:
+            results = podman.ListContainerChanges(self.id)
+        return results['container']
+
+    def kill(self, signal=signal.SIGTERM):
+        """Send signal to container, return id if successful.
+
+        default signal is signal.SIGTERM.
+        """
+        with self._client() as podman:
+            results = podman.KillContainer(self.id, signal)
+        return results['container']
+
+    def _lower_hook(self):
+        """Convert all keys to lowercase."""
+
+        @functools.wraps(self._lower_hook)
+        def wrapped(input):
+            return {k.lower(): v for (k, v) in input.items()}
+
+        return wrapped
+
+    def inspect(self):
+        """Retrieve details about containers."""
+        with self._client() as podman:
+            results = podman.InspectContainer(self.id)
+            obj = json.loads(
+                results['container'], object_hook=self._lower_hook())
+            return collections.namedtuple('ContainerInspect',
+                                          obj.keys())(**obj)
+
+    def export(self, target):
+        """Export container from store to tarball.
+
+        TODO: should there be a compress option, like images?
+        """
+        with self._client() as podman:
+            results = podman.ExportContainer(self.id, target)
+        return results['tarfile']
+
+    def start(self):
+        """Start container, return id on success."""
+        with self._client() as podman:
+            results = podman.StartContainer(self.id)
+        return results['container']
+
+    def stop(self, timeout=25):
+        """Stop container, return id on success."""
+        with self._client() as podman:
+            results = podman.StopContainer(self.id, timeout)
+        return results['container']
+
+    def remove(self, force=False):
+        """Remove container, return id on success.
+
+        force=True, stop running container.
+        """
+        with self._client() as podman:
+            results = podman.RemoveContainer(self.id, force)
+        return results['container']
+
+    def restart(self, timeout=25):
+        """Restart container with timeout, return id on success."""
+        with self._client() as podman:
+            results = podman.RestartContainer(self.id, timeout)
+        return results['container']
+
+    def rename(self, target):
+        """Rename container, return id on success."""
+        with self._client() as podman:
+            # TODO: Need arguements
+            results = podman.RenameContainer()
+        # TODO: fixup objects cached information
+        return results['container']
+
+    def resize_tty(self, width, height):
+        """Resize container tty."""
+        with self._client() as podman:
+            # TODO: magic re: attach(), arguements
+            podman.ResizeContainerTty()
+
+    def pause(self):
+        """Pause container, return id on success."""
+        with self._client() as podman:
+            results = podman.PauseContainer(self.id)
+        return results['container']
+
+    def unpause(self):
+        """Unpause container, return id on success."""
+        with self._client() as podman:
+            results = podman.UnpauseContainer(self.id)
+        return results['container']
+
+    def update_container(self, *args, **kwargs):
+        """TODO: Update container..., return id on success."""
+        with self._client() as podman:
+            results = podman.UpdateContainer()
+        self.refresh()
+        return results['container']
+
+    def wait(self):
+        """Wait for container to finish, return 'returncode'."""
+        with self._client() as podman:
+            results = podman.WaitContainer(self.id)
+        return int(results['exitcode'])
+
+    def stats(self):
+        """Retrieve resource stats from the container."""
+        with self._client() as podman:
+            results = podman.GetContainerStats(self.id)
+        obj = results['container']
+        return collections.namedtuple('StatDetail', obj.keys())(**obj)
+
+    def logs(self, *args, **kwargs):
+        """Retrieve container logs."""
+        with self._client() as podman:
+            results = podman.GetContainerLogs(self.id)
+        for line in results:
+            yield line
+
+
+class Containers(object):
+    """Model for Containers collection."""
+
+    def __init__(self, client):
+        """Construct model for Containers collection."""
+        self._client = client
+
+    def list(self):
+        """List of containers in the container store."""
+        with self._client() as podman:
+            results = podman.ListContainers()
+        for cntr in results['containers']:
+            yield Container(self._client, cntr['id'], cntr)
+
+    def delete_stopped(self):
+        """Delete all stopped containers."""
+        with self._client() as podman:
+            results = podman.DeleteStoppedContainers()
+        return results['containers']
+
+    def create(self, *args, **kwargs):
+        """Create container layer over the specified image.
+
+        See podman-create.1.md for kwargs details.
+        """
+        with self._client() as podman:
+            results = podman.CreateContainer()
+        return results['id']
+
+    def get(self, id):
+        """Retrieve container details from store."""
+        with self._client() as podman:
+            cntr = podman.GetContainer(id)
+        return Container(self._client, cntr['container']['id'],
+                         cntr['container'])
diff --git a/contrib/python/podman/libs/errors.py b/contrib/python/podman/libs/errors.py
new file mode 100644
index 000000000..c28afd940
--- /dev/null
+++ b/contrib/python/podman/libs/errors.py
@@ -0,0 +1,58 @@
+"""Error classes and wrappers for VarlinkError."""
+from varlink import VarlinkError
+
+
+class VarlinkErrorProxy(VarlinkError):
+    """Class to Proxy VarlinkError methods."""
+
+    def __init__(self, obj):
+        """Construct proxy from Exception."""
+        self._obj = obj
+        self.__module__ = 'libpod'
+
+    def __getattr__(self, item):
+        """Return item from proxied Exception."""
+        return getattr(self._obj, item)
+
+
+class ContainerNotFound(VarlinkErrorProxy):
+    """Raised when Client can not find requested container."""
+
+    pass
+
+
+class ImageNotFound(VarlinkErrorProxy):
+    """Raised when Client can not find requested image."""
+
+    pass
+
+
+class ErrorOccurred(VarlinkErrorProxy):
+    """Raised when an error occurs during the execution.
+
+    See error() to see actual error text.
+    """
+
+    pass
+
+
+class RuntimeError(VarlinkErrorProxy):
+    """Raised when Client fails to connect to runtime."""
+
+    pass
+
+
+error_map = {
+    'io.projectatomic.podman.ContainerNotFound': ContainerNotFound,
+    'io.projectatomic.podman.ErrorOccurred': ErrorOccurred,
+    'io.projectatomic.podman.ImageNotFound': ImageNotFound,
+    'io.projectatomic.podman.RuntimeError': RuntimeError,
+}
+
+
+def error_factory(exception):
+    """Map Exceptions to a discrete type."""
+    try:
+        return error_map[exception.error()](exception)
+    except KeyError:
+        return exception
diff --git a/contrib/python/podman/libs/images.py b/contrib/python/podman/libs/images.py
new file mode 100644
index 000000000..1d40984a7
--- /dev/null
+++ b/contrib/python/podman/libs/images.py
@@ -0,0 +1,137 @@
+"""Models for manipulating images in/to/from storage."""
+import collections
+import functools
+import json
+
+
+class Image(collections.UserDict):
+    """Model for an Image."""
+
+    def __init__(self, client, id, data):
+        """Construct Image Model."""
+        super(Image, self).__init__(data)
+        for k, v in data.items():
+            setattr(self, k, v)
+
+        self._id = id
+        self._client = client
+
+        assert self._id == self.id,\
+            'Requested image id({}) does not match store id({})'.format(
+                self._id, self.id
+            )
+
+    def __getitem__(self, key):
+        """Get items from parent dict."""
+        return super().__getitem__(key)
+
+    def export(self, dest, compressed=False):
+        """Write image to dest, return True on success."""
+        with self._client() as podman:
+            results = podman.ExportImage(self.id, dest, compressed)
+        return results['image']
+
+    def history(self):
+        """Retrieve image history."""
+        with self._client() as podman:
+            for r in podman.HistoryImage(self.id)['history']:
+                yield collections.namedtuple('HistoryDetail', r.keys())(**r)
+
+    def _lower_hook(self):
+        """Convert all keys to lowercase."""
+
+        @functools.wraps(self._lower_hook)
+        def wrapped(input):
+            return {k.lower(): v for (k, v) in input.items()}
+
+        return wrapped
+
+    def inspect(self):
+        """Retrieve details about image."""
+        with self._client() as podman:
+            results = podman.InspectImage(self.id)
+            obj = json.loads(results['image'], object_hook=self._lower_hook())
+            return collections.namedtuple('ImageInspect', obj.keys())(**obj)
+
+    def push(self, target, tlsverify=False):
+        """Copy image to target, return id on success."""
+        with self._client() as podman:
+            results = podman.PushImage(self.id, target, tlsverify)
+        return results['image']
+
+    def remove(self, force=False):
+        """Delete image, return id on success.
+
+        force=True, stop any running containers using image.
+        """
+        with self._client() as podman:
+            results = podman.RemoveImage(self.id, force)
+        return results['image']
+
+    def tag(self, tag):
+        """Tag image."""
+        with self._client() as podman:
+            results = podman.TagImage(self.id, tag)
+        return results['image']
+
+
+class Images(object):
+    """Model for Images collection."""
+
+    def __init__(self, client):
+        """Construct model for Images collection."""
+        self._client = client
+
+    def list(self):
+        """List all images in the libpod image store."""
+        with self._client() as podman:
+            results = podman.ListImages()
+        for img in results['images']:
+            yield Image(self._client, img['id'], img)
+
+    def create(self, *args, **kwargs):
+        """Create image from configuration."""
+        with self._client() as podman:
+            results = podman.CreateImage()
+        return results['image']
+
+    def create_from(self, *args, **kwargs):
+        """Create image from container."""
+        # TODO: Should this be on container?
+        with self._client() as podman:
+            results = podman.CreateFromContainer()
+        return results['image']
+
+    def build(self, *args, **kwargs):
+        """Build container from image.
+
+        See podman-build.1.md for kwargs details.
+        """
+        with self._client() as podman:
+            # TODO: Need arguments
+            podman.BuildImage()
+
+    def delete_unused(self):
+        """Delete Images not associated with a container."""
+        with self._client() as podman:
+            results = podman.DeleteUnusedImages()
+        return results['images']
+
+    def import_image(self, source, reference, message=None, changes=None):
+        """Read image tarball from source and save in image store."""
+        with self._client() as podman:
+            results = podman.ImportImage(source, reference, message, changes)
+        return results['image']
+
+    def pull(self, source):
+        """Copy image from registry to image store."""
+        with self._client() as podman:
+            results = podman.PullImage(source)
+        return results['id']
+
+    def search(self, id, limit=25):
+        """Search registries for id."""
+        with self._client() as podman:
+            results = podman.SearchImage(id)
+        for img in results['images']:
+            yield img
diff --git a/contrib/python/podman/libs/system.py b/contrib/python/podman/libs/system.py
new file mode 100644
index 000000000..c59867760
--- /dev/null
+++ b/contrib/python/podman/libs/system.py
@@ -0,0 +1,40 @@
+"""Models for accessing details from varlink server."""
+import collections
+
+import pkg_resources
+
+from . import cached_property
+
+
+class System(object):
+    """Model for accessing system resources."""
+
+    def __init__(self, client):
+        """Construct system model."""
+        self._client = client
+
+    @cached_property
+    def versions(self):
+        """Access versions."""
+        with self._client() as podman:
+            vers = podman.GetVersion()['version']
+
+        client = '0.0.0'
+        try:
+            client = pkg_resources.get_distribution('podman').version
+        except Exception:
+            pass
+        vers['client_version'] = client
+        return collections.namedtuple('Version', vers.keys())(**vers)
+
+    def info(self):
+        """Return podman info."""
+        with self._client() as podman:
+            info = podman.GetInfo()['info']
+        return collections.namedtuple('Info', info.keys())(**info)
+
+    def ping(self):
+        """Return True if server awake."""
+        with self._client() as podman:
+            response = podman.Ping()
+        return 'OK' == response['ping']['message']