Prevents the silencing of notifications that are actively deployed. (#454)

* Renaming 'active' to 'notify' as this is clearer and more aligned to what this value is actually controlling. 'active' is now a property that depends on whether any endpoints were found to be using the certificate. Also added logic for issue #405 disallowing for a certificates' notifications to be silenced when it is actively deployed on an endpoint.

* Adding migration script to alter 'active' column.

lemur/certificates/models.py

@@ -41,7 +41,7 @@ class Certificate(db.Model):
     owner = Column(String(128), nullable=False)
     name = Column(String(128), unique=True)
     description = Column(String(1024))
-    active = Column(Boolean, default=True)
+    notify = Column(Boolean, default=True)
 
     body = Column(Text(), nullable=False)
     chain = Column(Text())
@@ -114,6 +114,11 @@ class Certificate(db.Model):
         for domain in defaults.domains(cert):
             self.domains.append(Domain(name=domain))
 
+    @property
+    def active(self):
+        if self.endpoints:
+            return True
+
     @hybrid_property
     def expired(self):
         if self.not_after <= datetime.datetime.now():
@@ -195,5 +200,7 @@ def protect_active(mapper, connection, target):
     :return:
     """
     if target.active:
-        if target.replaced:
-            raise Exception("Cannot mark certificate as active, certificate has been marked as replaced.")
+        if not target.notify:
+            raise Exception(
+                "Cannot silence notification for a certificate Lemur has been found to be currently deployed onto endpoints"
+            )