Add ability to resize existing partition (#773)

* Add ability to resize existing partition

* Add 'resize' flag to support backwards compatability, and allow partition reduction

* Add changelog fragment for #773

* Update changelogs/fragments/773-resize-partition.yml

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

* Update plugins/modules/system/parted.py

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

* Update resize flag with PR review comments

Co-authored-by: Andrew Klychkov <aaklychkov@mail.ru>

* Update plugins/modules/system/parted.py

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

* Update default on resize flag in parted.py

* Apply suggestions from code review

Co-authored-by: Felix Fontein <felix@fontein.de>
Co-authored-by: Andrew Klychkov <aaklychkov@mail.ru>

changelogs/fragments/773-resize-partition.yml

@@ -0,0 +1,2 @@
+minor_changes:
+  - parted - add ``resize`` option to resize existing partitions (https://github.com/ansible-collections/community.general/pull/773).

plugins/modules/system/parted.py

@@ -103,6 +103,13 @@ options:
      - Parameter optional, but see notes below about negative negative C(part_start) values.
     type: str
     version_added: '0.2.0'
+  resize:
+    description:
+      - Call C(resizepart) on existing partitions to match the size specified by I(part_end).
+    type: bool
+    default: false
+    version_added: '1.3.0'
+
 notes:
   - When fetching information about a new disk and when the version of parted
     installed on the system is before version 3.1, the module queries the kernel
@@ -207,6 +214,13 @@ EXAMPLES = r'''
     number: '{{ item.num }}'
     state: absent
   loop: '{{ sdb_info.partitions }}'
+
+- name: Extend an existing partition to fill all available space
+  community.general.parted:
+    decice: /dev/sdb
+    number: "{{ sdb_info.partitions | length }}"
+    part_end: "100%"
+    resize: true
 '''
 
 
@@ -392,6 +406,21 @@ def format_disk_size(size_bytes, unit):
     return round(output, precision), unit
 
 
+def convert_to_bytes(size_str, unit):
+    size = float(size_str)
+    multiplier = 1.0
+    if unit in units_si:
+        multiplier = 1000.0 ** units_si.index(unit)
+    elif unit in units_iec:
+        multiplier = 1024.0 ** (units_iec.index(unit) + 1)
+    elif unit in ['', 'compact', 'cyl', 'chs']:
+        # As per format_disk_size, default to compact, which defaults to megabytes
+        multiplier = 1000.0 ** units_si.index("MB")
+
+    output = size * multiplier
+    return int(output)
+
+
 def get_unlabeled_device_info(device, unit):
     """
     Fetches device information directly from the kernel and it is used when
@@ -586,6 +615,9 @@ def main():
 
             # rm/mkpart command
             state=dict(type='str', default='info', choices=['absent', 'info', 'present']),
+
+            # resize part
+            resize=dict(type='bool', default=False),
         ),
         required_if=[
             ['state', 'present', ['number']],
@@ -608,6 +640,7 @@ def main():
     state = module.params['state']
     flags = module.params['flags']
     fs_type = module.params['fs_type']
+    resize = module.params['resize']
 
     # Parted executable
     parted_exec = module.get_bin_path('parted', True)
@@ -652,6 +685,25 @@ def main():
         if unit and script:
             script = "unit %s %s" % (unit, script)
 
+        # If partition exists, try to resize
+        if resize and part_exists(current_parts, 'num', number):
+            # Ensure new end is different to current
+            partition = [p for p in current_parts if p['num'] == number][0]
+            current_part_end = convert_to_bytes(partition['end'], unit)
+
+            size, parsed_unit = parse_unit(part_end, unit)
+            if parsed_unit == "%":
+                size = int((int(current_device['generic']['size']) * size) / 100)
+                parsed_unit = unit
+
+            desired_part_end = convert_to_bytes(size, parsed_unit)
+
+            if current_part_end != desired_part_end:
+                script += "resizepart %s %s " % (
+                    number,
+                    part_end
+                )
+
         # Execute the script and update the data structure.
         # This will create the partition for the next steps
         if script:

tests/unit/plugins/modules/system/test_parted.py

@@ -206,6 +206,17 @@ class TestParted(ModuleTestCase):
         with patch('ansible_collections.community.general.plugins.modules.system.parted.get_device_info', return_value=parted_dict1):
             self.execute_module(changed=True, script='rm 1')
 
+    def test_resize_partition(self):
+        set_module_args({
+            'device': '/dev/sdb',
+            'number': 3,
+            'state': 'present',
+            'part_end': '100%',
+            'resize': True
+        })
+        with patch('ansible_collections.community.general.plugins.modules.system.parted.get_device_info', return_value=parted_dict1):
+            self.execute_module(changed=True, script='resizepart 3 100%')
+
     def test_change_flag(self):
         # Flags are set in a second run of parted().
         # Between the two runs, the partition dict is updated.