Merge pull request #12 from fedora-infra/feature/rule-negation

Allow individual rules to be negated.

alembic/versions/18ebf3181f87_add_a_negated_column_for_rules.py

@@ -0,0 +1,22 @@
+"""Add a negated column for rules.
+
+Revision ID: 18ebf3181f87
+Revises: 4a95022fd7f3
+Create Date: 2014-08-22 15:48:08.952913
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '18ebf3181f87'
+down_revision = '4a95022fd7f3'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.add_column('rules', sa.Column('negated', sa.Boolean(), default=False))
+
+
+def downgrade():
+    op.drop_column('rules', 'negated')

fmn/lib/__init__.py

@@ -71,12 +71,16 @@ def matches(filter, message, valid_paths, rule_cache, config):
 
     for rule in filter['rules']:
         fn = rule['fn']
+        negated = rule['negated']
         arguments = rule['arguments']
         rule_cache_key = rule['cache_key']
 
         try:
             if rule_cache_key not in rule_cache:
-                rule_cache[rule_cache_key] = fn(config, message, **arguments)
+                value = fn(config, message, **arguments)
+                if negated:
+                    value = not value
+                rule_cache[rule_cache_key] =  value
 
             if not rule_cache[rule_cache_key]:
                 return False

fmn/lib/models.py

@@ -240,21 +240,25 @@ class Rule(BASE):
     code_path = sa.Column(sa.String(50), nullable=False)
     # JSON-encoded kw
     _arguments = sa.Column(sa.String(256))
+    # Should we negate the output of the computed rule?
+    negated = sa.Column(sa.Boolean, default=False)
 
     def __json__(self, reify=False):
         result = {
             'created_on': self.created_on,
             'code_path': self.code_path,
             'arguments': self.arguments,
             'cache_key': self.cache_key,
+            'negated': self.negated,
         }
         if reify:
             result['fn'] = fedmsg.utils.load_class(str(self.code_path))
         return result
 
     def __repr__(self):
-        return "<fmn.lib.models.Rule: %r(**%r)>" % (
-            self.code_path, self.arguments)
+        negation = self.negated and '!' or ''
+        return "<fmn.lib.models.Rule: %s%r(**%r)>" % (
+            negation, self.code_path, self.arguments)
 
     @property
     def cache_key(self):
@@ -365,6 +369,20 @@ def remove_rule(self, session, code_path, **kw):
 
         raise ValueError("No such rule found: %r" % code_path)
 
+    def negate_rule(self, session, code_path, **kw):
+        for r in self.rules:
+            if r.code_path == code_path:
+                r.negated = not r.negated
+                session.commit()
+
+                pref = self.preference
+                if pref:
+                    self.notify(pref.openid, pref.context_name, "rules")
+
+                return
+
+        raise ValueError("No such rule found: %r" % code_path)
+
 
 class DetailValue(BASE):
     __tablename__ = 'detail_values'