Create swapoff module

Create custome ansible module 'swapoff' to idempotently
disable swap in /etc/fstab and also run swapoff.

1 files changed, 137 insertions, 0 deletions

diff --git a/roles/lib_utils/library/swapoff.py b/roles/lib_utils/library/swapoff.py
new file mode 100644
index 000000000..925eeb17d
--- /dev/null
+++ b/roles/lib_utils/library/swapoff.py
@@ -0,0 +1,137 @@
+#!/usr/bin/env python
+# pylint: disable=missing-docstring
+#
+# Copyright 2017 Red Hat, Inc. and/or its affiliates
+# and other contributors as indicated by the @author tags.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import subprocess
+
+from ansible.module_utils.basic import AnsibleModule
+
+
+DOCUMENTATION = '''
+---
+module: swapoff
+
+short_description: Disable swap and comment from /etc/fstab
+
+version_added: "2.4"
+
+description:
+    - This module disables swap and comments entries from /etc/fstab
+
+author:
+    - "Michael Gugino <mgugino@redhat.com>"
+'''
+
+EXAMPLES = '''
+# Pass in a message
+- name: Disable Swap
+  swapoff: {}
+'''
+
+
+def check_swap_in_fstab(module):
+    '''Check for uncommented swap entries in fstab'''
+    res = subprocess.call(['grep', '^[^#].*swap', '/etc/fstab'])
+
+    if res == 2:
+        # rc 2 == cannot open file.
+        result = {'failed': True,
+                  'changed': False,
+                  'msg': 'unable to read /etc/fstab',
+                  'state': 'unknown'}
+        module.fail_json(**result)
+    elif res == 1:
+        # No grep match, fstab looks good.
+        return False
+    elif res == 0:
+        # There is an uncommented entry for fstab.
+        return True
+    else:
+        # Some other grep error code, we shouldn't get here.
+        result = {'failed': True,
+                  'changed': False,
+                  'msg': 'unknow problem with grep "^[^#].*swap" /etc/fstab ',
+                  'state': 'unknown'}
+        module.fail_json(**result)
+
+
+def check_swapon_status(module):
+    '''Check if swap is actually in use.'''
+    try:
+        res = subprocess.check_output(['swapon', '--show'])
+    except subprocess.CalledProcessError:
+        # Some other grep error code, we shouldn't get here.
+        result = {'failed': True,
+                  'changed': False,
+                  'msg': 'unable to execute swapon --show',
+                  'state': 'unknown'}
+        module.fail_json(**result)
+    return 'NAME' in str(res)
+
+
+def comment_swap_fstab(module):
+    '''Comment out swap lines in /etc/fstab'''
+    res = subprocess.call(['sed', '-i.bak', 's/^[^#].*swap.*/#&/', '/etc/fstab'])
+    if res:
+        result = {'failed': True,
+                  'changed': False,
+                  'msg': 'sed failed to comment swap in /etc/fstab',
+                  'state': 'unknown'}
+        module.fail_json(**result)
+
+
+def run_swapoff(module, changed):
+    '''Run swapoff command'''
+    res = subprocess.call(['swapoff', '--all'])
+    if res:
+        result = {'failed': True,
+                  'changed': changed,
+                  'msg': 'swapoff --all returned {}'.format(str(res)),
+                  'state': 'unknown'}
+        module.fail_json(**result)
+
+
+def run_module():
+    '''Run this module'''
+    module = AnsibleModule(
+        supports_check_mode=False,
+        argument_spec={}
+    )
+    changed = False
+
+    swap_fstab_res = check_swap_in_fstab(module)
+    swap_is_inuse_res = check_swapon_status(module)
+
+    if swap_fstab_res:
+        comment_swap_fstab(module)
+        changed = True
+
+    if swap_is_inuse_res:
+        run_swapoff(module, changed)
+        changed = True
+
+    result = {'changed': changed}
+
+    module.exit_json(**result)
+
+
+def main():
+    run_module()
+
+
+if __name__ == '__main__':
+    main()