Vendor API connection code from Docker SDK for Python (#398)

* Vendor parts of the Docker SDK for Python

This is a combination of the latest git version
(https://github.com/docker/docker-py/tree/a48a5a9647761406d66e8271f19fab7fa0c5f582)
and the version before Python 2.7 support was removed
(https://github.com/docker/docker-py/tree/650aad3a5fb84059b392ad450f760ed08143ae3f),
including some modifications to work with Ansible module_utils's
system (i.e. third-party imports are guarded, and errors are
reported during runtime through a new exception
MissingRequirementException).

* Create module_utils and plugin_utils for working with the vendored code.

The delete call cannot be called delete() since that method already exists from requests.

* Vendor more code from Docker SDK for Python.

* Adjust code from common module_utils.

* Add unit tests from Docker SDK for Python.

* Make test compile with Python 2.6, but skip them on Python 2.6.

* Skip test that requires a network server.

* Add changelog.

* Update changelogs/fragments/398-docker-api.yml

Co-authored-by: Brian Scholer <1260690+briantist@users.noreply.github.com>

* Minimum API version is 1.25.

Co-authored-by: Brian Scholer <1260690+briantist@users.noreply.github.com>

plugins/module_utils/_api/credentials/store.py

@@ -0,0 +1,118 @@
+# -*- coding: utf-8 -*-
+# This code is part of the Ansible collection community.docker, but is an independent component.
+# This particular file, and this file only, is based on the Docker SDK for Python (https://github.com/docker/docker-py/)
+#
+# Copyright (c) 2016-2022 Docker, Inc.
+#
+# It is licensed under the Apache 2.0 license (see Apache-2.0.txt in this collection)
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+import errno
+import json
+import subprocess
+
+from ansible.module_utils.six import PY3, binary_type
+
+from . import constants
+from . import errors
+from .utils import create_environment_dict
+from .utils import find_executable
+
+
+class Store(object):
+    def __init__(self, program, environment=None):
+        """ Create a store object that acts as an interface to
+            perform the basic operations for storing, retrieving
+            and erasing credentials using `program`.
+        """
+        self.program = constants.PROGRAM_PREFIX + program
+        self.exe = find_executable(self.program)
+        self.environment = environment
+        if self.exe is None:
+            raise errors.InitializationError(
+                '{0} not installed or not available in PATH'.format(
+                    self.program
+                )
+            )
+
+    def get(self, server):
+        """ Retrieve credentials for `server`. If no credentials are found,
+            a `StoreError` will be raised.
+        """
+        if not isinstance(server, binary_type):
+            server = server.encode('utf-8')
+        data = self._execute('get', server)
+        result = json.loads(data.decode('utf-8'))
+
+        # docker-credential-pass will return an object for inexistent servers
+        # whereas other helpers will exit with returncode != 0. For
+        # consistency, if no significant data is returned,
+        # raise CredentialsNotFound
+        if result['Username'] == '' and result['Secret'] == '':
+            raise errors.CredentialsNotFound(
+                'No matching credentials in {0}'.format(self.program)
+            )
+
+        return result
+
+    def store(self, server, username, secret):
+        """ Store credentials for `server`. Raises a `StoreError` if an error
+            occurs.
+        """
+        data_input = json.dumps({
+            'ServerURL': server,
+            'Username': username,
+            'Secret': secret
+        }).encode('utf-8')
+        return self._execute('store', data_input)
+
+    def erase(self, server):
+        """ Erase credentials for `server`. Raises a `StoreError` if an error
+            occurs.
+        """
+        if not isinstance(server, binary_type):
+            server = server.encode('utf-8')
+        self._execute('erase', server)
+
+    def list(self):
+        """ List stored credentials. Requires v0.4.0+ of the helper.
+        """
+        data = self._execute('list', None)
+        return json.loads(data.decode('utf-8'))
+
+    def _execute(self, subcmd, data_input):
+        output = None
+        env = create_environment_dict(self.environment)
+        try:
+            if PY3:
+                output = subprocess.check_output(
+                    [self.exe, subcmd], input=data_input, env=env,
+                )
+            else:
+                process = subprocess.Popen(
+                    [self.exe, subcmd], stdin=subprocess.PIPE,
+                    stdout=subprocess.PIPE, env=env,
+                )
+                output, dummy = process.communicate(data_input)
+                if process.returncode != 0:
+                    raise subprocess.CalledProcessError(
+                        returncode=process.returncode, cmd='', output=output
+                    )
+        except subprocess.CalledProcessError as e:
+            raise errors.process_store_error(e, self.program)
+        except OSError as e:
+            if e.errno == errno.ENOENT:
+                raise errors.StoreError(
+                    '{0} not installed or not available in PATH'.format(
+                        self.program
+                    )
+                )
+            else:
+                raise errors.StoreError(
+                    'Unexpected OS error "{0}", errno={1}'.format(
+                        e.strerror, e.errno
+                    )
+                )
+        return output