Make fileystem module idemponent. Compare devicesize and filesystemsize.

system/filesystem.py

@@ -63,6 +63,50 @@ EXAMPLES = '''
 - filesystem: fstype=ext4 dev=/dev/sdb1 opts="-cc"
 '''
 
+def _get_dev_size(dev, module):
+    """ Return size in bytes of device. Returns int """
+    blockdev_cmd = module.get_bin_path("blockdev", required=True)
+    rc, devsize_in_bytes, err = module.run_command("%s %s %s" % (blockdev_cmd, "--getsize64", dev))
+    return int(devsize_in_bytes)
+
+
+def _get_fs_size(fssize_cmd, dev, module):
+    """ Return size in bytes of filesystem on device. Returns int """
+    cmd = module.get_bin_path(fssize_cmd, required=True)
+    if 'tune2fs' == fssize_cmd:
+        # Get Block count and Block size
+        rc, size, err = module.run_command("%s %s %s" % (cmd, '-l', dev))
+        if rc == 0:
+            for line in size.splitlines():
+                if 'Block count:' in line:
+                    block_count = int(line.split(':')[1].strip())
+                elif 'Block size:' in line:
+                    block_size = int(line.split(':')[1].strip())
+                    break
+        else:
+            module.fail_json(msg="Failed to get block count and block size of %s with %s" % (dev, cmd), rc=rc, err=err )
+    elif 'xfs_info' == fssize_cmd:
+        # Get Block count and Block size
+        rc, size, err = module.run_command("%s %s" % (cmd, dev))
+        if rc == 0:
+            for line in size.splitlines():
+                #if 'data' in line:
+                if 'data ' in line:
+                    block_size = int(line.split('=')[2].split()[0])
+                    block_count = int(line.split('=')[3].split(',')[0])
+                    break
+        else:
+            module.fail_json(msg="Failed to get block count and block size of %s with %s" % (dev, cmd), rc=rc, err=err )
+    elif 'btrfs' == fssize_cmd:
+        #ToDo
+        # There is no way to get the blocksize and blockcount for btrfs filesystems
+        block_size = 1
+        block_count = 1
+
+
+    return block_size*block_count
+
+
 def main():
     module = AnsibleModule(
         argument_spec = dict(
@@ -82,36 +126,42 @@ def main():
             'grow' : 'resize2fs',
             'grow_flag' : None,
             'force_flag' : '-F',
+            'fsinfo': 'tune2fs',
         },
         'ext3' : {
             'mkfs' : 'mkfs.ext3',
             'grow' : 'resize2fs',
             'grow_flag' : None,
             'force_flag' : '-F',
+            'fsinfo': 'tune2fs',
         },
         'ext4' : {
             'mkfs' : 'mkfs.ext4',
             'grow' : 'resize2fs',
             'grow_flag' : None,
             'force_flag' : '-F',
+            'fsinfo': 'tune2fs',
         },
         'ext4dev' : {
             'mkfs' : 'mkfs.ext4',
             'grow' : 'resize2fs',
             'grow_flag' : None,
             'force_flag' : '-F',
+            'fsinfo': 'tune2fs',
         },
         'xfs' : {
             'mkfs' : 'mkfs.xfs',
             'grow' : 'xfs_growfs',
             'grow_flag' : None,
             'force_flag' : '-f',
+            'fsinfo': 'xfs_info',
         },
         'btrfs' : {
             'mkfs' : 'mkfs.btrfs',
             'grow' : 'btrfs',
             'grow_flag' : 'filesystem resize',
             'force_flag' : '-f',
+            'fsinfo': 'btrfs',
         }
     }
 
@@ -131,6 +181,7 @@ def main():
     mkfscmd = fs_cmd_map[fstype]['mkfs']
     force_flag = fs_cmd_map[fstype]['force_flag']
     growcmd = fs_cmd_map[fstype]['grow']
+    fssize_cmd = fs_cmd_map[fstype]['fsinfo']
 
     if not os.path.exists(dev):
         module.fail_json(msg="Device %s not found."%dev)
@@ -143,10 +194,21 @@ def main():
     if fs == fstype and resizefs == False:
         module.exit_json(changed=False)
     elif fs == fstype and resizefs == True:
-        cmd = module.get_bin_path(growcmd, required=True)
+        # Get dev and fs size and compare
-        if module.check_mode:
+        devsize_in_bytes = _get_dev_size(dev, module)
-            module.exit_json(changed=True, msg="May resize filesystem")
+        fssize_in_bytes = _get_fs_size(fssize_cmd, dev, module)
+        if fssize_in_bytes < devsize_in_bytes:
+            fs_smaller = True
         else:
+            fs_smaller = False
+
+
+        if module.check_mode and fs_smaller:
+            module.exit_json(changed=True, msg="Resizing filesystem %s on device %s" % (fstype,dev))
+        elif module.check_mode and not fs_smaller:
+            module.exit_json(changed=False, msg="%s filesystem is using the whole device %s" % (fstype, dev))
+        elif fs_smaller:
+            cmd = module.get_bin_path(growcmd, required=True)
             rc,out,err = module.run_command("%s %s" % (cmd, dev))
             # Sadly there is no easy way to determine if this has changed. For now, just say "true" and move on.
             #  in the future, you would have to parse the output to determine this.
@@ -155,6 +217,8 @@ def main():
                 module.exit_json(changed=True, msg=out)
             else:
                 module.fail_json(msg="Resizing filesystem %s on device '%s' failed"%(fstype,dev), rc=rc, err=err)
+        else:
+            module.exit_json(changed=False, msg="%s filesystem is using the whole device %s" % (fstype, dev))
     elif fs and not force:
         module.fail_json(msg="'%s' is already used as %s, use force=yes to overwrite"%(dev,fs), rc=rc, err=err)
 
@@ -180,4 +244,5 @@ def main():
 
 # import module snippets
 from ansible.module_utils.basic import *
-main()
+if __name__ == '__main__':
+    main()