nbd-proxy: Add state hook facility
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/README b/README
index d5ab82e..0d3030e 100644
--- a/README
+++ b/README
@@ -53,3 +53,13 @@
There is no authentication or authorisation implemented in the nbd proxy. Your
websocket proxy should implement proper authentication before nbd-proxy is
connected to the websocket endpoint.
+
+State hooks
+-----------
+
+The nbd-proxy has a facility to run hooks on state change. When a
+nbd session is established or shut down, the proxy will run any executables
+found under the hook path (by default, /etc/nbd-proxy/state.d/).
+
+These hooks are called with two arguments: the action ("start" or "stop"),
+and the name of the configuration (as specified in the config.json file).