feat(middleware): common method write_if_changed

src/middlewared/middlewared/etc_files/loader.py

@@ -1,22 +1,15 @@
 import logging
-import os
 import subprocess
 import sysctl
 
+from middlewared.utils.io import write_if_changed
+
 logger = logging.getLogger(__name__)
 
 
 def loader_config(middleware):
     config = generate_loader_config(middleware)
-
-    with open(os.open("/boot/loader.conf.local", os.O_CREAT | os.O_RDWR), "w+") as f:
-        f.seek(0)
-        data = f.read()
-        new = "\n".join(config) + "\n"
-        if data != new:
-            f.seek(0)
-            f.write(new)
-            f.truncate()
+    write_if_changed("/boot/loader.conf.local", "\n".join(config) + "\n")
 
 
 def generate_loader_config(middleware):

src/middlewared/middlewared/etc_files/rc.conf.py

@@ -6,6 +6,8 @@
 import subprocess
 import sysctl
 
+from middlewared.utils.io import write_if_changed
+
 NFS_BINDIP_NOTFOUND = '/tmp/.nfsbindip_notfound'
 RE_FIRMWARE_VERSION = re.compile(r'Firmware Revision\s*:\s*(\S+)', re.M)
 
@@ -444,16 +446,5 @@ def render(service, middleware):
         except Exception:
             middleware.logger.error('Failed to generate %s', i.__name__, exc_info=True)
 
-    with open(os.open('/etc/rc.conf.freenas', os.O_CREAT | os.O_RDWR), 'w+') as f:
-        f.seek(0)
-        current = f.read()
-        new = '\n'.join(rcs) + '\n'
-        if current != new:
-            f.seek(0)
-            f.write('\n'.join(rcs) + '\n')
-            f.truncate()
-        os.fsync(f)
-
-    # Signal init later to make sure the file is synced to filesystem
-    if current != new:
+    if write_if_changed('/etc/rc.conf.freenas', '\n'.join(rcs) + '\n'):
         os.kill(1, signal.SIGALRM)

src/middlewared/middlewared/plugins/etc.py

@@ -1,10 +1,10 @@
 from mako import exceptions
 from mako.lookup import TemplateLookup
 from middlewared.service import Service
+from middlewared.utils.io import write_if_changed
 
 import asyncio
 import grp
-import hashlib
 import imp
 import os
 import pwd
@@ -249,24 +249,7 @@ async def generate(self, name):
                 continue
 
             outfile = '/etc/{0}'.format(entry['path'])
-            changes = False
-
-            # Check hash of generated and existing file
-            # Do not rewrite if they are the same
-            if os.path.exists(outfile):
-                with open(outfile, 'rb') as f:
-                    existing_hash = hashlib.sha256(f.read()).hexdigest()
-
-                new_hash = hashlib.sha256(rendered.encode('utf-8')).hexdigest()
-                if existing_hash != new_hash:
-                    with open(outfile, 'w') as f:
-                        f.write(rendered)
-                        changes = True
-
-            if not os.path.exists(outfile):
-                with open(outfile, 'w') as f:
-                    f.write(rendered)
-                changes = True
+            changes = write_if_changed(outfile, rendered)
 
             # If ownership or permissions are specified, see if
             # they need to be changed.

src/middlewared/middlewared/utils/io.py

@@ -0,0 +1,21 @@
+import os
+
+
+def write_if_changed(path, data):
+
+    if isinstance(data, str):
+        data = data.encode()
+
+    changed = False
+
+    with open(os.open(path, os.O_CREAT | os.O_RDWR), 'wb+') as f:
+        f.seek(0)
+        current = f.read()
+        if current != data:
+            changed = True
+            f.seek(0)
+            f.write(data)
+            f.truncate()
+        os.fsync(f)
+
+    return changed