configuration.lua

local configuration = {}

local safer = require("safer")
local schema = require("schema")

function configuration.read(filename)
   local config_fd = io.open(filename, "r")
   if not config_fd then
      return nil, "Could not read config file "..filename
   end
   local config_data = config_fd:read("*a")
   config_fd:close()
   
   local config = {}
   local chunk, err = load(config_data, filename, "t", config)
   if not chunk then
      return nil, "Failed loading config file "..filename..": "..err
   end
   config.os = { getenv = os.getenv }
   config.tonumber = tonumber
   local ok, err = pcall(chunk)
   config.os = nil
   if not ok then
      return nil, "Failed processing config file "..filename..": "..err
   end
   config = safer.readonly(config)
   return config
end

function configuration.check(config)
   local config_schema = schema.Record {
      csbase_server = schema.Pattern("https?://.*"),
      platform = schema.String,
      sgad_host = schema.String,
      sgad_port = schema.NumberFrom(1,65535),
      sga_name = schema.Pattern("[A-Za-z0-9_%-]+"),
      sga_type = schema.Optional(schema.String),
      status_interval_s = schema.PositiveNumber,
      exec_polling_interval_s = schema.PositiveNumber,
      driver = schema.Test(function(v)
         local ok, err = pcall(require, v)
         if not ok then
            io.stderr:write("Failed loading driver '"..tostring(v).."': "..err.."\n")
         end
         return ok
      end, "must be a valid module"),
      driver_config = schema.Optional(schema.Map(schema.String, schema.Any)),
      resources = schema.Optional(schema.Collection(schema.String)),
      extra_config = schema.Optional(schema.Map(schema.String, schema.Any)),
   }
   local err = schema.CheckSchema(config, config_schema)
   if err then
      io.stderr:write("Configuration error: "..tostring(err).."\n")
      os.exit(1)
   end
end

return configuration