WIP: New module: diff (string, file or command output vs string, file or command output)

lib/ansible/modules/files/diff.py

@@ -0,0 +1,253 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# (c) 2017, cytopia <cytopia@everythingcli.org>
+#
+# This module is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This software is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this software.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+ANSIBLE_METADATA = {'metadata_version': '1.1',
+                    'status': ['preview'],
+                    'supported_by': 'community'}
+
+DOCUMENTATION = '''
+---
+module: diff
+author: cytopia (@cytopia)
+
+short_description: Diff compare strings, files or command outputs
+description:
+    - Diff compare a string, file or command output against a string file or command output.
+    - Check mode is only supported when diffing strings or files, commands will only be executed in actual run.
+    - More examples at U(https://github.com/cytopia/ansible-modules)
+version_added: "2.4"
+options:
+    source:
+        description:
+            - The source input to diff. Can be a string, contents of a file or output from a command, depending on I(source_type).
+        required: true
+        default: null
+        aliases: []
+
+    target:
+        description:
+            - The target input to diff. Can be a string, contents of a file or output from a command, depending on I(target_type).
+        required: true
+        default: null
+        aliases: []
+
+    source_type:
+        description:
+            - Specify the input type of I(source).
+        required: true
+        default: string
+        choices: [ string, file, command ]
+        aliases: []
+
+    target_type:
+        description:
+            - Specify the input type of I(target).
+        required: true
+        default: string
+        choices: [ string, file, command ]
+        aliases: []
+'''
+
+EXAMPLES = '''
+# Diff compare two strings
+- diff:
+    source: "foo"
+    target: "bar"
+    source_type: string
+    target_type: string
+
+# Diff compare variable against template file (as strings)
+- diff:
+    source: "{{ lookup('template', tpl.yml.j2) }}"
+    target: "{{ my_var }}"
+    source_type: string
+    target_type: string
+
+# Diff compare string against command output
+- diff:
+    source: "/bin/bash"
+    target: "which bash"
+    source_type: string
+    target_type: command
+
+# Diff compare file against command output
+- diff:
+    source: "/etc/hostname"
+    target: "hostname"
+    source_type: file
+    target_type: command
+'''
+
+RETURN = '''
+diff:
+    description: diff output
+    returned: success
+    type: string
+    sample: + this line was added
+'''
+
+# Python default imports
+import os
+import time
+import subprocess
+
+# Python Ansible imports
+from ansible.module_utils.basic import AnsibleModule
+from ansible.module_utils._text import to_bytes
+
+
+def shell_exec(command):
+    '''
+    Execute raw shell command and return exit code and output
+    '''
+    cpt = subprocess.Popen(command, shell=True,
+                           stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+
+    output = []
+    for line in iter(cpt.stdout.readline, ''):
+        output.append(line)
+
+    # Wait until process terminates (without using p.wait())
+    while cpt.poll() is None:
+        # Process hasn't exited yet, let's wait some
+        time.sleep(0.5)
+
+    # Get return code from process
+    return_code = cpt.returncode
+
+    # Return code and output
+    return return_code, output
+
+
+def diff_module_validation(module):
+    '''
+    Validate for correct module call/usage in ansible.
+    '''
+    source = module.params.get('source')
+    target = module.params.get('target')
+    source_type = module.params.get('source_type')
+    target_type = module.params.get('target_type')
+
+    # Validate source
+    if source_type == 'file':
+        b_source = to_bytes(source, errors='surrogate_or_strict')
+        if not os.path.exists(b_source):
+            module.fail_json(msg="source %s not found" % (source))
+        if not os.access(b_source, os.R_OK):
+            module.fail_json(msg="source %s not readable" % (source))
+        if os.path.isdir(b_source):
+            module.fail_json(msg="diff does not support recursive diff of directory: %s" % (source))
+
+    # Validate target
+    if target_type == 'file':
+        b_target = to_bytes(target, errors='surrogate_or_strict')
+        if not os.path.exists(b_target):
+            module.fail_json(msg="target %s not found" % (target))
+        if not os.access(b_target, os.R_OK):
+            module.fail_json(msg="target %s not readable" % (target))
+        if os.path.isdir(b_target):
+            module.fail_json(msg="diff does not support recursive diff of directory: %s" % (target))
+
+    return module
+
+
+def main():
+    '''
+    Main function
+    '''
+    module = AnsibleModule(
+        argument_spec=dict(
+            source=dict(required=True, default=None, type='str'),
+            target=dict(required=True, default=None, type='str'),
+            source_type=dict(required=True, default='string',
+                             choices=['string', 'file', 'command']),
+            target_type=dict(required=True, default='string',
+                             choices=['string', 'file', 'command']),
+        ),
+        supports_check_mode=True
+    )
+
+    # Validate module
+    module = diff_module_validation(module)
+
+    # Get ansible arguments
+    source = module.params.get('source')
+    target = module.params.get('target')
+    source_type = module.params.get('source_type')
+    target_type = module.params.get('target_type')
+
+    # Source file to string
+    if source_type == 'file':
+        with open(source, 'rt') as fpt:
+            source = fpt.read().decode("UTF-8")
+    # Source command to string
+    elif source_type == 'command':
+        if module.check_mode:
+            result = dict(
+                changed=False,
+                msg="This module does not support check mode when source_type is 'command'.",
+                skipped=True
+            )
+            module.exit_json(**result)
+        else:
+            ret, source = shell_exec(source)
+            if ret != 0:
+                module.fail_json(msg="source command failed: %s" % (source))
+
+    # Targe file to string
+    if target_type == 'file':
+        with open(target, 'rt') as fpt:
+            target = fpt.read().decode("UTF-8")
+    # Target command to string
+    elif target_type == 'command':
+        if module.check_mode:
+            result = dict(
+                changed=False,
+                msg="This module does not support check mode when target_type is 'command'.",
+                skipped=True
+            )
+            module.exit_json(**result)
+        else:
+            ret, target = shell_exec(target)
+            if ret != 0:
+                module.fail_json(msg="target command failed: %s" % (target))
+
+    # Ansible diff output
+    diff = {
+        'before': target,
+        'after': source,
+    }
+    # Did we have any changes?
+    changed = (source != target)
+
+    # Ansible module returned variables
+    result = dict(
+        diff=diff,
+        changed=changed
+    )
+
+    # Exit ansible module call
+    module.exit_json(**result)
+
+
+if __name__ == '__main__':
+    main()