Bundle a lua script for generating a bat-hosts

alfred/Makefile

@@ -12,7 +12,7 @@ include $(TOPDIR)/rules.mk
 #
 PKG_NAME:=alfred
 PKG_VERSION:=2013.3.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 PKG_MD5SUM:=018ef6262cdd11e900af31d71a864b13
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
@@ -74,6 +74,8 @@ define Package/alfred/install
 	$(INSTALL_BIN) ./files/alfred.init $(1)/etc/init.d/alfred
 	$(INSTALL_DIR) $(1)/etc/config
 	$(INSTALL_DATA) ./files/alfred.config $(1)/etc/config/alfred
+	$(INSTALL_DIR) $(1)/etc/alfred
+	$(INSTALL_BIN) ./files/bat-hosts.lua $(1)/etc/alfred/bat-hosts.lua
 endef
 
 $(eval $(call BuildPackage,alfred))

alfred/files/bat-hosts.lua

@@ -0,0 +1,80 @@
+#!/usr/bin/lua
+
+local nxo = require "nixio"
+
+local type_id = 64  -- bat-hosts
+
+local function generate_bat_hosts()
+-- get hostname and interface macs/names
+-- then return a table containing valid bat-hosts lines
+  local n, i
+  local ifaces, ret = {}, {}
+
+  local hostname = nxo.uname().nodename
+
+  -- skip loopback ("lo") mac (00:00:00:00:00:00)
+  for n, i in ipairs(nxo.getifaddrs()) do
+    if i.addr:match("%x%x:%x%x:%x%x:%x%x:%x%x:%x%x")
+    and not i.addr:match("00:00:00:00:00:00") then
+      ifaces[i.addr] = i.name:match("[^:]+")
+    end
+  end
+
+  for mac, iname in pairs(ifaces) do
+    table.insert(ret, mac.." "..hostname.."_"..iname.."\n")
+  end
+
+  return ret
+end
+
+local function publish_bat_hosts()
+-- pass a raw chunk of data to alfred
+  local fd = io.popen("alfred -s " .. type_id, "w")
+  if fd then
+    local ret = generate_bat_hosts()
+    if ret then
+      fd:write(table.concat(ret))
+    end
+    fd:close()
+  end
+end
+
+local function write_bat_hosts(rows)
+  local content = { "### File generated by alfred-mod-bat-hosts\n" }
+
+  -- merge the chunks from all nodes, de-escaping newlines
+  for _, row in ipairs(rows)  do
+    local node, value = unpack(row)
+    table.insert(content, "# Node ".. node .. "\n")
+    table.insert(content, value:gsub("\x0a", "\n") .. "\n")
+  end
+
+  -- write parsed content down to disk
+  local fd = io.open("/tmp/bat-hosts", "w")
+  if fd then
+    fd:write(table.concat(content))
+    fd:close()
+  end
+end
+
+local function receive_bat_hosts()
+-- read raw chunks from alfred, convert them to a nested table and call write_bat_hosts
+
+  local fd = io.popen("alfred -r " .. type_id)
+    --[[ this command returns something like
+    { "54:e6:fc:b9:cb:37", "00:11:22:33:44:55 ham_wlan0\x0a00:22:33:22:33:22 ham_eth0\x0a" },
+    { "90:f6:52:bb:ec:57", "00:22:33:22:33:23 spam\x0a" },
+    ]]--
+
+  if fd then
+      local output = fd:read("*a")
+      if output then
+        assert(loadstring("rows = {" .. output .. "}"))()
+        write_bat_hosts(rows)
+      end
+      fd:close()
+  end
+end
+
+publish_bat_hosts()
+receive_bat_hosts()