Implemented enough to wake up a sleepy server by connecting nodemcu to dc power

3 files changed, 104 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..fee9217
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.conf
diff --git a/init.lua b/init.lua
new file mode 100644
index 0000000..1756628
--- /dev/null
+++ b/init.lua
@@ -0,0 +1,22 @@
+--- Somewhat safely loads "run.lua" module into a global variable RUN. Loaded module itself should be a function. If
+--- everything seems fine, true is returned.
+function init ()
+	wifi.setmode(wifi.NULLMODE, false)
+	local l, r = pcall(require, "run")
+	if not l then
+		print("run.lua not found")
+		return
+	end
+	RUN = r
+	l, r = node.bootreason()
+	if l == 2 and (r == 2 or r == 4) then
+		print("Most likely an exception restarted last boot, run.lua loaded into RUN and left as is")
+		return
+	end
+	return true
+end
+
+
+if init() then
+	RUN()
+end
diff --git a/run.lua b/run.lua
new file mode 100644
index 0000000..3c22c30
--- /dev/null
+++ b/run.lua
@@ -0,0 +1,81 @@
+local wol = {
+	port = 9,
+	timer = tmr.create(),
+}
+
+
+--- Reads configuration file at [[path]] and parses a pair of MAC and broadcast addresses from it. Builds a Wake-on-LAN
+--- magic packet and saves it for later use with :worker(). Returns true if no errors were encountered, otherwise a nil.
+function wol:configure (path)
+	local fd = file.open(path)
+	if not fd then
+		print("Config file not found", path)
+		return
+	end
+	local line = fd:readline()
+	fd:close()
+	fd = nil
+	self.mac, self.addr = line:match("^(%S+)%s+(%S+)")
+	self.data = ""
+	for octet in self.mac:gmatch("%x%x") do
+		self.data = self.data .. string.char(tonumber(octet, 16))
+	end
+	if #self.data ~= 6 then
+		print(string.format("Invalid MAC\t%q", self.mac))
+		return
+	end
+	self.data = string.char(0xff):rep(6) .. self.data:rep(16)
+	return true
+end
+
+
+--- Initializes and returns worker that implements :sendout(interval, times, callback) that attempts to wake up
+--- designated host number of [[times]] each separated by [[interval]]. After all attempts [[callback]] is called.
+function wol:worker ()
+	return {
+		config = self,
+		udp = net.createUDPSocket(),
+		timer = tmr.create(),
+		count = 0,
+		sendout = function (self, interval, times, cb)
+			self.times = times
+			return self.timer:alarm(interval, tmr.ALARM_SEMI, function (timer)
+				self.count = self.count + 1
+				if self.count <= self.times then
+					print("Waking up", self.config.mac, self.config.addr)
+					self.udp:send(self.config.port, self.config.addr, self.config.data)
+					timer:start()
+				else
+					timer:unregister()
+					cb()
+				end
+			end)
+		end,
+	}
+end
+
+
+wol.timer:register(1000, tmr.ALARM_SINGLE, function ()
+	gpio.mode(4, gpio.OUTPUT)
+	gpio.write(4, gpio.HIGH)
+	if not wol:configure("wakeup.conf") then
+		error("Could not configure wakeup")
+	end
+	wifi.setmode(wifi.STATION, false)
+
+	wifi.eventmon.register(wifi.eventmon.STA_GOT_IP, function ()
+		local waker = wol:worker()
+		gpio.write(4, gpio.LOW)
+		waker:sendout(500, 5, function ()
+			wifi.setmode(wifi.NULLMODE, false)
+			gpio.write(4, gpio.HIGH)
+		end)
+	end)
+
+	wifi.sta.connect()
+end)
+
+
+return function ()
+	wol.timer:start()
+end