diff options
Diffstat (limited to 'plugin/pkg/fall/fall.go')
| -rw-r--r-- | plugin/pkg/fall/fall.go | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/plugin/pkg/fall/fall.go b/plugin/pkg/fall/fall.go index c8cdc6ff6..067deb9a6 100644 --- a/plugin/pkg/fall/fall.go +++ b/plugin/pkg/fall/fall.go @@ -1,4 +1,16 @@ -// Package fall handles the fallthrough logic used in plugins that support it. +// Package fall handles the fallthrough logic used in plugins that support it. Be careful when including this +// functionality in your plugin. Why? In the DNS only 1 source is authoritative for a set of names. Fallthrough +// breaks this convention by allowing a plugin to query multiple sources, depending on the replies it got sofar. +// +// This may cause issues in downstream caches, where different answers for the same query can potentially confuse clients. +// On the other hand this is a powerful feature that can aid in migration or other edge cases. +// +// The take away: be mindful of this and don't blindly assume it's a good feature to have in your plugin. +// +// See http://github.com/coredns/coredns/issues/2723 for some discussion on this, which includes this quote: +// +// TL;DR: `fallthrough` is indeed risky and hackish, but still a good feature of CoreDNS as it allows to quickly answer boring edge cases. +// package fall import ( |