Detailed logging for decryption/validation

lib/decrypt_mails.rb

@@ -11,6 +11,15 @@ module InstanceMethods
 
     def receive_with_encryption(email, options={})
 
+      # Extract useful metadata for logging
+      sender_email = email.from.to_a.first.to_s.strip
+      # We need to store this before decryption, because after decryption
+      # email.encrypted? == false
+      encrypted = email.encrypted?
+      # Sometimes this isn't available after decryption. This seems like a bug,
+      # so extract it here so we're guaranteed to have it
+      message_id = email.message_id
+
       # encrypt and check validity of signature
       if email.encrypted?
         email = email.decrypt(
@@ -32,7 +41,6 @@ def receive_with_encryption(email, options={})
       # compare identity of signature with sender
       if valid
         valid = false
-        sender_email = email.from.to_a.first.to_s.strip
         user = User.find_by_mail sender_email if sender_email.present?
         key = Pgpkey.find_by user_id: user.id
         signatures.each do |s|
@@ -41,10 +49,17 @@ def receive_with_encryption(email, options={})
       end
 
       # error on invalid signature
-      if Setting.plugin_openpgp['signature_needed'] and not valid
-        if logger
-          logger.info "MailHandler: ignoring emails with invalid signature"
-        end
+      ignored = !!(Setting.plugin_openpgp['signature_needed'] and not valid)
+
+      if logger
+        logger.info "MailHandler: received email from #{sender_email} " +
+                    "with Message-ID #{message_id}: " +
+                    "encrypted=#{encrypted}, " +
+                    "valid=#{valid}, "+
+                    "ignored=#{ignored}"
+      end
+
+      if ignored
         return false
       end
 
@@ -53,4 +68,4 @@ def receive_with_encryption(email, options={})
     end
 
   end
-end
+end