From 3f3848f78e3379e15cb814edd4eb9eb0ea831369 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Marek=20Vavru=C5=A1a?= <marek.vavrusa@nic.cz>
Date: Thu, 2 Jul 2015 22:09:22 +0200
Subject: [PATCH] prefetch wip

---
 daemon/ffimodule.c            |  4 ++--
 modules/modules.mk            |  3 ++-
 modules/prefetch/README.rst   |  4 ++++
 modules/prefetch/prefetch.lua | 45 +++++++++++++++++++++++++++++++++++
 modules/prefetch/prefetch.mk  |  2 ++
 5 files changed, 55 insertions(+), 3 deletions(-)
 create mode 100644 modules/prefetch/README.rst
 create mode 100644 modules/prefetch/prefetch.lua
 create mode 100644 modules/prefetch/prefetch.mk

diff --git a/daemon/ffimodule.c b/daemon/ffimodule.c
index 902991552..c6cc77883 100644
--- a/daemon/ffimodule.c
+++ b/daemon/ffimodule.c
@@ -180,8 +180,8 @@ static int l_ffi_layer_consume(knot_layer_t *ctx, knot_pkt_t *pkt)
 
 static int l_ffi_layer_produce(knot_layer_t *ctx, knot_pkt_t *pkt)
 {
-	if (ctx->state & (KNOT_STATE_FAIL|KNOT_STATE_DONE)) {
-		return ctx->state; /* Already resolved/failed, skip */
+	if (ctx->state & (KNOT_STATE_FAIL)) {
+		return ctx->state; /* Already failed, skip */
 	}
 	LAYER_FFI_CALL(ctx, "produce");
 	lua_pushlightuserdata(L, ctx->data);
diff --git a/modules/modules.mk b/modules/modules.mk
index 171771459..583e842f3 100644
--- a/modules/modules.mk
+++ b/modules/modules.mk
@@ -16,7 +16,8 @@ endif
 ifeq ($(HAS_lua),yes)
 modules_TARGETS += ketcd \
                    graphite \
-                   block
+                   block \
+                   prefetch
 endif
 
 # List of Golang modules
diff --git a/modules/prefetch/README.rst b/modules/prefetch/README.rst
new file mode 100644
index 000000000..fefb476d9
--- /dev/null
+++ b/modules/prefetch/README.rst
@@ -0,0 +1,4 @@
+.. _mod-prefetch:
+
+Prefetching
+-----------
diff --git a/modules/prefetch/prefetch.lua b/modules/prefetch/prefetch.lua
new file mode 100644
index 000000000..4035cad4a
--- /dev/null
+++ b/modules/prefetch/prefetch.lua
@@ -0,0 +1,45 @@
+local prefetch = {
+	queue = {},
+	frequency = 2
+}
+
+-- @function Block layer implementation
+prefetch.layer = {
+	produce = function(state, req, pkt)
+		-- Schedule cached entries that are expiring soon
+		local qry = kres.query_current(req)
+		if not kres.query_has_flag(qry, kres.query.CACHED) then
+			return state
+		end
+		local rr = pkt:get(kres.ANSWER, 0)
+		if rr and rr.ttl > 0 and rr.ttl < prefetch.frequency then
+			local key = rr.owner..rr.type
+			local val = prefetch.queue[key]
+			if not val then
+				prefetch.queue[key] = 1
+			else
+				prefetch.queue[key] = val + 1
+			end
+		end
+		return state
+	end
+}
+
+function prefetch.batch(module)
+	for key, val in pairs(prefetch.queue) do
+		print('prefetching',key,val)
+	end
+	prefetch.queue = {}
+	-- @TODO: next batch interval
+	event.after(prefetch.frequency * sec, prefetch.batch)
+end
+
+function prefetch.init(module)
+	event.after(prefetch.frequency * sec, prefetch.batch)
+end
+
+function prefetch.deinit(module)
+	if prefetch.ev then event.cancel(prefetch.ev) end
+end
+
+return prefetch
diff --git a/modules/prefetch/prefetch.mk b/modules/prefetch/prefetch.mk
new file mode 100644
index 000000000..a4867745f
--- /dev/null
+++ b/modules/prefetch/prefetch.mk
@@ -0,0 +1,2 @@
+prefetch_SOURCES := prefetch.lua
+$(call make_lua_module,prefetch)
-- 
2.47.2