Add shared state multiwriter

packages/lime-system/files/usr/lib/lua/lime/utils.lua

@@ -543,4 +543,21 @@ function utils.is_valid_mac(string)
     end
 end
 
+function utils.deepcompare(t1,t2)
+    if t1 == t2 then return true end
+    local ty1 = type(t1)
+    local ty2 = type(t2)
+    if ty1 ~= ty2 then return false end
+    if ty1 ~= 'table' and ty2 ~= 'table' then return t1 == t2 end
+    for k1, v1 in pairs(t1) do
+        local v2 = t2[k1]
+        if v2 == nil or not utils.deepcompare(v1, v2) then return false end
+    end
+    for k2, v2 in pairs(t2) do
+        local v1 = t1[k2]
+        if v1 == nil or not utils.deepcompare(v1, v2) then return false end
+    end
+    return true
+end
+
 return utils

packages/shared-state/files/usr/bin/shared-state-multiwriter

@@ -0,0 +1,57 @@
+#!/usr/bin/lua
+--! Minimalistic CRDT-like shared state structure suitable for mesh networks
+--! which handles conflicts in the same entry using last modified timestamp.
+--!
+--! Copyright (C) 2019  Gioacchino Mazzurco <gio@altermundi.net>
+--!
+--! This program is free software: you can redistribute it and/or modify
+--! it under the terms of the GNU Affero General Public License version 3 as
+--! published by the Free Software Foundation.
+--!
+--! This program is distributed in the hope that it will be useful,
+--! but WITHOUT ANY WARRANTY; without even the implied warranty of
+--! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--! GNU Affero General Public License for more details.
+--!
+--! You should have received a copy of the GNU Affero General Public License
+--! along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+if type(arg[2]) ~= "string" or arg[2]:len() < 1 then
+	print (arg[0], "needs CRDT name to be specified as second argument")
+	os.exit(-22)
+end
+
+local JSON = require("luci.jsonc")
+local shared_state = require("shared-state")
+require("nixio.util")
+
+nixio.openlog("shared-state")
+local logmask = "info"
+if os.getenv("DEBUG") then
+	logmask = "debug"
+end
+nixio.setlogmask(logmask)
+
+local sharedState = shared_state.SharedStateMultiWriter:new(arg[2], nixio.syslog)
+
+if arg[1] == "insert" then
+	local inputTable = JSON.parse(io.stdin:read("*all")) or {}
+	sharedState:insert(inputTable)
+elseif arg[1] == "get" then
+	local resultTable = sharedState:get()
+	print(JSON.stringify(resultTable))
+elseif arg[1] == "sync" then
+	local urls = {}
+	if arg[3] ~= nil then for i=3,#arg do table.insert(urls, arg[i]) end end
+	sharedState:sync(urls)
+elseif arg[1] == "reqsync" then
+	local inputJson = JSON.parse(io.stdin:read("*all"))
+	sharedState:merge(inputJson)
+	print(sharedState:toJsonString())
+else
+	print(arg[0], "needs an operation name to be specified as first argument")
+	nixio.closelog()
+	os.exit(-22)
+end
+
+nixio.closelog()