filesystem: fix 355 state absent (#1149) (#1184)

* add support for filesystem removal (fix #355)

- Add 'state' option, defaults to 'present'.
- When state=absent, ignore other options (even 'dev' if the device
  doesn't exist)

* test filesystem state=absent (+ check_mode + idempotency)

* fix doc-required-mismatch

* add changelog fragment

* fix blkid return code

* ext4dev may be deprecated

* base checks on UUID instead

* Update changelogs/fragments/1149-filesystem-fix-355-state-absent.yml

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/system/filesystem.py (version_added)

Co-authored-by: Felix Fontein <felix@fontein.de>

* use array for new run_command() calls; do not wipefs if no fs found

* use dd as a fallback

* do not use bare 'except' (pep8)

* force string type

* use dd anyway (wipefs not supported everywhere, possibly buggy with vfat, etc.)

* do not truncate regular files; update changelog fragment

* doc: update state description and an example; notice check_mode support

* do not wipe mounted fs, fail instead

* back to wipefs implementation

* update test's main conditions

* update changelog fragment

* explicit types

* fail state=absent on freebsd

* remove doc-missing-type exceptions (2.9, 2.10, 2.11)

Co-authored-by: Felix Fontein <felix@fontein.de>
(cherry picked from commit a5ca990857)

Co-authored-by: quidame <quidame@poivron.org>

tests/integration/targets/filesystem/tasks/main.yml

@@ -43,7 +43,12 @@
     - 'not (item.0.key == "f2fs" and ansible_distribution == "Ubuntu" and ansible_distribution_version is version("14.04", "<="))'
     - 'not (item.1 == "overwrite_another_fs" and ansible_system == "FreeBSD")'
 
+    - 'not (item.1 == "remove_fs" and ansible_system == "FreeBSD")' # util-linux not available on FreeBSD
+    # On CentOS 6 shippable containers, wipefs seems unable to remove vfat signatures
+    - 'not (item.1 == "remove_fs" and item.0.key == "vfat" and ansible_distribution == "CentOS" and
+            ansible_distribution_version is version("7.0", "<"))'
+
     # The xfsprogs package on newer versions of OpenSUSE (15+) require Python 3, we skip this on our Python 2 container
     # OpenSUSE 42.3 Python2 and the other py3 containers are not affected so we will continue to run that
     - 'not (item.0.key == "xfs" and ansible_os_family == "Suse" and ansible_python.version.major == 2 and ansible_distribution_major_version|int != 42)'
-  loop: "{{ query('dict', tested_filesystems)|product(['create_fs', 'overwrite_another_fs'])|list }}"
+  loop: "{{ query('dict', tested_filesystems)|product(['create_fs', 'overwrite_another_fs', 'remove_fs'])|list }}"

tests/integration/targets/filesystem/tasks/remove_fs.yml

@@ -0,0 +1,98 @@
+---
+# We assume 'create_fs' tests have passed.
+
+- name: filesystem creation
+  filesystem:
+    dev: '{{ dev }}'
+    fstype: '{{ fstype }}'
+
+- name: get filesystem UUID with 'blkid'
+  command:
+    cmd: 'blkid -c /dev/null -o value -s UUID {{ dev }}'
+  changed_when: false
+  register: blkid_ref
+
+- name: Assert that a filesystem exists on top of the device
+  assert:
+    that:
+      - blkid_ref.stdout | length > 0
+
+
+# Test check_mode first
+- name: filesystem removal (check mode)
+  filesystem:
+    dev: '{{ dev }}'
+    state: absent
+  register: wipefs
+  check_mode: yes
+
+- name: get filesystem UUID with 'blkid' (should remain the same)
+  command:
+    cmd: 'blkid -c /dev/null -o value -s UUID {{ dev }}'
+  changed_when: false
+  register: blkid
+
+- name: Assert that the state changed but the filesystem still exists
+  assert:
+    that:
+      - wipefs is changed
+      - blkid.stdout == blkid_ref.stdout
+
+# Do it
+- name: filesystem removal
+  filesystem:
+    dev: '{{ dev }}'
+    state: absent
+  register: wipefs
+
+- name: get filesystem UUID with 'blkid' (should be empty)
+  command:
+    cmd: 'blkid -c /dev/null -o value -s UUID {{ dev }}'
+  changed_when: false
+  failed_when: false
+  register: blkid
+
+- name: Assert that the state changed and the device has no filesystem
+  assert:
+    that:
+      - wipefs is changed
+      - blkid.stdout | length == 0
+      - blkid.rc == 2
+
+# Do it again
+- name: filesystem removal (idempotency)
+  filesystem:
+    dev: '{{ dev }}'
+    state: absent
+  register: wipefs
+
+- name: Assert that the state did not change
+  assert:
+    that:
+      - wipefs is not changed
+
+# and again
+- name: filesystem removal (idempotency, check mode)
+  filesystem:
+    dev: '{{ dev }}'
+    state: absent
+  register: wipefs
+  check_mode: yes
+
+- name: Assert that the state did not change
+  assert:
+    that:
+      - wipefs is not changed
+
+
+# By the way, test removal of a filesystem on unexistent device
+- name: filesystem removal (unexistent device)
+  filesystem:
+    dev: '/dev/unexistent_device'
+    state: absent
+  register: wipefs
+
+- name: Assert that the state did not change
+  assert:
+    that:
+      - wipefs is not changed