Add gpg_fingerprint lookup and filter (#639)

* Add gpg_fingerprint lookup.

* Work around problems on some CI targets.

* Use get_bin_path to find the gpg executable. Document that we need it.

* Improve and test error handling.

* Refactor (potentially) common code to module_utils and plugin_utils.

This will be useful to create a filter version of this, and further lookups, filters, and modules.

* Do not create a keyring when there isn't one.

* Fixups.

* Fix description.

* More fixes for lookup.

* Also add a gpg_fingerprint filter.

* Improve formulation.

Co-authored-by: Sandra McCann <samccann@redhat.com>

---------

Co-authored-by: Sandra McCann <samccann@redhat.com>

plugins/filter/gpg_fingerprint.py

@@ -0,0 +1,68 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2023, Felix Fontein <felix@fontein.de>
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+DOCUMENTATION = """
+name: gpg_fingerprint
+short_description: Retrieve a GPG fingerprint from a GPG public or private key
+author: Felix Fontein (@felixfontein)
+version_added: 2.15.0
+description:
+  - "Takes the content of a private or public GPG key as input and returns its fingerprint."
+options:
+  _input:
+    description:
+      - The content of a GPG public or private key.
+    type: string
+    required: true
+requirements:
+  - GnuPG (C(gpg) executable)
+seealso:
+  - plugin: community.crypto.gpg_fingerprint
+    plugin_type: lookup
+"""
+
+EXAMPLES = """
+- name: Show fingerprint of GPG public key
+  ansible.builtin.debug:
+    msg: "{{ lookup('file', '/path/to/public_key.gpg') | community.crypto.gpg_fingerprint }}"
+"""
+
+RETURN = """
+  _value:
+    description:
+      - The fingerprint of the provided public or private GPG key.
+    type: string
+"""
+
+from ansible.errors import AnsibleFilterError
+from ansible.module_utils.common.text.converters import to_bytes, to_native
+from ansible.module_utils.six import string_types
+
+from ansible_collections.community.crypto.plugins.module_utils.gnupg.cli import GPGError, get_fingerprint_from_bytes
+from ansible_collections.community.crypto.plugins.plugin_utils.gnupg import PluginGPGRunner
+
+
+def gpg_fingerprint(input):
+    if not isinstance(input, string_types):
+        raise AnsibleFilterError(
+            'The input for the community.crypto.gpg_fingerprint filter must be a string; got {type} instead'.format(type=type(input))
+        )
+    try:
+        gpg = PluginGPGRunner()
+        return get_fingerprint_from_bytes(gpg, to_bytes(input))
+    except GPGError as exc:
+        raise AnsibleFilterError(to_native(exc))
+
+
+class FilterModule(object):
+    '''Ansible jinja2 filters'''
+
+    def filters(self):
+        return {
+            'gpg_fingerprint': gpg_fingerprint,
+        }

plugins/lookup/gpg_fingerprint.py

@@ -0,0 +1,64 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2023, Felix Fontein <felix@fontein.de>
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+DOCUMENTATION = """
+name: gpg_fingerprint
+short_description: Retrieve a GPG fingerprint from a GPG public or private key file
+author: Felix Fontein (@felixfontein)
+version_added: 2.15.0
+description:
+  - "Takes a list of filenames pointing to GPG public or private key files. Returns the fingerprints for each of these keys."
+options:
+  _terms:
+    description:
+      - A path to a GPG public or private key.
+    type: list
+    elements: path
+    required: true
+requirements:
+  - GnuPG (C(gpg) executable)
+seealso:
+  - plugin: community.crypto.gpg_fingerprint
+    plugin_type: filter
+"""
+
+EXAMPLES = """
+- name: Show fingerprint of GPG public key
+  ansible.builtin.debug:
+    msg: "{{ lookup('community.crypto.gpg_fingerprint', '/path/to/public_key.gpg') }}"
+"""
+
+RETURN = """
+  _value:
+    description:
+      - The fingerprints of the provided public or private GPG keys.
+      - The list has one entry for every path provided.
+    type: list
+    elements: string
+"""
+
+from ansible.plugins.lookup import LookupBase
+from ansible.errors import AnsibleLookupError
+from ansible.module_utils.common.text.converters import to_native
+
+from ansible_collections.community.crypto.plugins.module_utils.gnupg.cli import GPGError, get_fingerprint_from_file
+from ansible_collections.community.crypto.plugins.plugin_utils.gnupg import PluginGPGRunner
+
+
+class LookupModule(LookupBase):
+    def run(self, terms, variables=None, **kwargs):
+        self.set_options(direct=kwargs)
+
+        try:
+            gpg = PluginGPGRunner(cwd=self._loader.get_basedir())
+            result = []
+            for path in terms:
+                result.append(get_fingerprint_from_file(gpg, path))
+            return result
+        except GPGError as exc:
+            raise AnsibleLookupError(to_native(exc))

plugins/module_utils/gnupg/cli.py

@@ -0,0 +1,64 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2023, Felix Fontein <felix@fontein.de>
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+import abc
+import os
+
+from ansible.module_utils import six
+
+
+class GPGError(Exception):
+    pass
+
+
+@six.add_metaclass(abc.ABCMeta)
+class GPGRunner(object):
+    @abc.abstractmethod
+    def run_command(self, command, check_rc=True, data=None):
+        """
+        Run ``[gpg] + command`` and return ``(rc, stdout, stderr)``.
+
+        If ``data`` is not ``None``, it will be provided as stdin.
+        The code assumes it is a bytes string.
+
+        Returned stdout and stderr are native Python strings.
+        Pass ``check_rc=False`` to allow return codes != 0.
+
+        Raises a ``GPGError`` in case of errors.
+        """
+        pass
+
+
+def get_fingerprint_from_stdout(stdout):
+    lines = stdout.splitlines(False)
+    for line in lines:
+        if line.startswith('fpr:'):
+            parts = line.split(':')
+            if len(parts) <= 9 or not parts[9]:
+                raise GPGError('Result line "{line}" does not have fingerprint as 10th component'.format(line=line))
+            return parts[9]
+    raise GPGError('Cannot extract fingerprint from stdout "{stdout}"'.format(stdout=stdout))
+
+
+def get_fingerprint_from_file(gpg_runner, path):
+    if not os.path.exists(path):
+        raise GPGError('{path} does not exist'.format(path=path))
+    stdout = gpg_runner.run_command(
+        ['--no-keyring', '--with-colons', '--import-options', 'show-only', '--import', path],
+        check_rc=True,
+    )[1]
+    return get_fingerprint_from_stdout(stdout)
+
+
+def get_fingerprint_from_bytes(gpg_runner, content):
+    stdout = gpg_runner.run_command(
+        ['--no-keyring', '--with-colons', '--import-options', 'show-only', '--import', '/dev/stdin'],
+        data=content,
+        check_rc=True,
+    )[1]
+    return get_fingerprint_from_stdout(stdout)

plugins/plugin_utils/gnupg.py

@@ -0,0 +1,51 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2023, Felix Fontein <felix@fontein.de>
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+from subprocess import Popen, PIPE
+
+from ansible.module_utils.common.process import get_bin_path
+from ansible.module_utils.common.text.converters import to_native
+
+from ansible_collections.community.crypto.plugins.module_utils.gnupg.cli import GPGError, GPGRunner
+
+
+class PluginGPGRunner(GPGRunner):
+    def __init__(self, executable=None, cwd=None):
+        if executable is None:
+            try:
+                executable = get_bin_path('gpg')
+            except ValueError as e:
+                raise GPGError('Cannot find the `gpg` executable on the controller')
+        self.executable = executable
+        self.cwd = cwd
+
+    def run_command(self, command, check_rc=True, data=None):
+        """
+        Run ``[gpg] + command`` and return ``(rc, stdout, stderr)``.
+
+        If ``data`` is not ``None``, it will be provided as stdin.
+        The code assumes it is a bytes string.
+
+        Returned stdout and stderr are native Python strings.
+        Pass ``check_rc=False`` to allow return codes != 0.
+
+        Raises a ``GPGError`` in case of errors.
+        """
+        command = [self.executable] + command
+        p = Popen(command, shell=False, cwd=self.cwd, stdin=PIPE, stdout=PIPE, stderr=PIPE)
+        stdout, stderr = p.communicate(input=data)
+        stdout = to_native(stdout, errors='surrogate_or_replace')
+        stderr = to_native(stderr, errors='surrogate_or_replace')
+        if check_rc and p.returncode != 0:
+            raise GPGError('Running {cmd} yielded return code {rc} with stdout: "{stdout}" and stderr: "{stderr}")'.format(
+                cmd=' '.join(command),
+                rc=p.returncode,
+                stdout=to_native(stdout, errors='surrogate_or_replace'),
+                stderr=to_native(stderr, errors='surrogate_or_replace'),
+            ))
+        return p.returncode, stdout, stderr