slapformat: WIP: Improve exception interception in dry-run mode

slapos/format.py

@@ -125,14 +125,17 @@ class FormatConfig(Parameters, Options):
   def __init__(self, logger):
     self.logger = logger
 
-  def wrong(self, fmt, *args):
-    return self.error(fmt, *args, exc=UsageError)
-
-  def error(self, fmt, *args):
+  def abort(self, fmt, *args):
     message = fmt % tuple(args)
     self.logger.error(message)
     raise ValueError(message)
 
+  def wrong(self, fmt, *args):
+    return self.abort(fmt, *args, exc=UsageError)
+
+  def dryError(self, fmt, *args):
+    self.logger.warning('[dry-error] ' + fmt, *args)
+
   def warn(self, fmt, *args):
     self.logger.warning(fmt, *args)
 
@@ -311,7 +314,7 @@ class Interface(object):
     try:
       addresses = netifaces.ifaddresses(self.ipv6_interface)[AF_INET6]
     except KeyError:
-      self.conf.error(
+      self.conf.abort(
         "%s must have at least one IPv6 address assigned",
         self.ipv6_interface
       )
@@ -338,7 +341,7 @@ class Interface(object):
     network = self.ipv6_network
     prefixlen = network.prefixlen + 16
     if prefixlen > 128:
-      self.conf.error("IPv6 network %s is too small for IPv6 ranges", network)
+      self.conf.abort("IPv6 network %s is too small for IPv6 ranges", network)
     bits = 128 - network.prefixlen
     addr = network[(1 << (bits - 2)) + (index << (128 - prefixlen))]
     return ipaddress.IPv6Network((addr, prefixlen))
@@ -359,7 +362,7 @@ class Interface(object):
       if iface != interface:
         ifaddresses = netifaces.ifaddresses(iface).get(af, ())
         if address in (q['addr'].split('%')[0] for q in ifaddresses):
-          self.conf.error(
+          self.conf.abort(
             "Cannot add address %s (%s) to %s because it already exists on %s",
             ip, reason, interface, iface
           )
@@ -367,7 +370,7 @@ class Interface(object):
     for q in ifaddresses:
       if address == q['addr'].split('%')[0]:
         if netmask not in q['netmask']:
-           self.conf.error(
+           self.conf.abort(
             "Address %s (%s) is already on %s but with another netmask %s",
             ip, reason, interface, q['netmask']
           )
@@ -385,13 +388,12 @@ class Interface(object):
         for state in ('tentative', 'dadfailed'):
           if state in line:
             call(['ip', 'addr', 'del', address, 'dev', interface])
-            self.conf.error(
+            self.conf.abort(
               "Address %s (%s) on %s was in state %s so was removed: %r",
               ip, reason, interface, state, line
             )
         return
-    report = self.conf.warn if self.conf.dry_run else self.conf.error
-    report(
+    self.conf.abort(
       "Address %s (%s) is unexpectedly not present on %s",
       ip, reason, interface
     )
@@ -569,6 +571,7 @@ class WrappedSystem(object):
     self.call = call
     self.os = os
     self.pwd = pwd
+    self.abort = conf.abort
 
   def __enter__(self):
     global call, os, pwd
@@ -587,8 +590,12 @@ class WrappedSystem(object):
       getpwnam=type('fake_getpwnam', (), {'pw_uid': 12345, 'pw_gid': 54321}),
     )
     if conf.dry_run:
+      conf.abort = conf.dryError
       def dry_call(args, raise_on_error=True):
         conf.logger.debug(' '.join(args))
+        it = iter(args)
+        if all(w in it for w in ('ip', 'addr', 'show')): # subsequence test
+          return self.call(args, raise_on_error=False)
         return 0, ''
       call = dry_call
     else:
@@ -602,5 +609,5 @@ class WrappedSystem(object):
     call = self.call
     os = self.os
     pwd = self.pwd
+    self.conf.abort = self.abort
     return False
-    
\ No newline at end of file