andrewhampton · March 24, 2015 18:39 · Mar 24, 2015
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,30 @@
+require "string"
+os = require "os"
+alert = require "alert"
+
+local alert_threshold      = read_config("alert_threshold") or 5
+local alert_throttle_time  = read_config("alert_throttle_time") or 300
+local nanosecondsInASecond = 1000000000
+
+alert.set_throttle(alert_throttle_time * nanosecondsInASecond)
+
+function process_message ()
+    local buffers     = read_message("Fields[Buffers]")
+    local cached      = read_message("Fields[Cached]")
+    local memFree     = read_message("Fields[MemFree]")
+    local memTotal    = read_message("Fields[MemTotal]")
+    local pctMemFree  = ((buffers + cached + memFree) / memTotal) * 100
+
+    local host        = read_message("Hostname")
+    local currentTime = os.time() * nanosecondsInASecond
+
+    if pctMemFree < alert_threshold and not alert.throttled(currentTime) then
+        local payload = string.format("Low Memory on %s, only %d percent free", host, pctMemFree)
+        alert.send(currentTime, payload)
+    end
+
+    return 0
+end
+
+function timer_event(ns)
+end