merge_experiments.lua

#!/usr/bin/lua

-- BUILT-IN/EXTERNAL MODULES
require('os')
require('io')
require('uci')

-- BISMARK (BMLUA) MODULES
require('bmlua.path')
path = bmlua.path
-- `require('foo.bar'); bar = foo.bar;`
-- is the equivalent of python's `import foo.bar as bar`

------------------------------------------------------------------------------
-- GLOBALS
------------------------------------------------------------------------------
UCI_DIR = '/etc/config'
UCI_CONFIG = 'bismark-experiments'
DEBUG = true

------------------------------------------------------------------------------
-- CONSTANTS
------------------------------------------------------------------------------
UCI_TRUE = '1'
UCI_FALSE = '0'

------------------------------------------------------------------------------
-- PUBLIC FUNCTIONS
------------------------------------------------------------------------------
function main(arg)
    pdebug("DEBUG MODE ON\n")

    local remote_fullpath
    local remote_dirpath
    local remote_filename
    local remote_uci
    local local_fullpath
    local local_dirpath
    local local_filename
    local local_uci

    if #arg ~= 1 then
        print("  USAGE: " .. arg[0] .. " REMOTE_CONFIG_FILE")
        os.exit(1)
    end

    remote_fullpath = path.abspath(arg[1])
    remote_dirpath = path.dirname(remote_fullpath)
    remote_filename = path.basename(remote_fullpath)
    if not path.exists(remote_fullpath) then
        print(string.format("Remote experiment UCI file %q not found",
                remote_fullpath))
        os.exit(1)
    end

    if DEBUG ~= nil and DEBUG == true then
        UCI_DIR = 'etc_config'
    end
    local_fullpath = path.abspath(path.join(UCI_DIR, UCI_CONFIG))
    local_dirpath = path.dirname(local_fullpath)
    local_filename = path.basename(local_fullpath)
    if not path.exists(local_dirpath) then
        print(string.format("Local config directory %q not found", dirpath))
        os.exit(1)
    end
    if not path.exists(local_fullpath) then
        pdebug("UCI file %q does not exist; 'touch'ing.\n", local_fullpath)
        os.execute(string.format('touch %s', local_fullpath))
    end

    remote_uci = uci.cursor(remote_dirpath)
    if DEBUG then
        local_uci = uci.cursor(local_dirpath)
    else
        local_uci = uci.cursor()
    end

    update_local_experiment_list(UCI_CONFIG, local_uci, remote_uci)
    local_uci:save(UCI_CONFIG)
    local_uci:commit(UCI_CONFIG)
end


function update_local_experiment_list(config, local_uci, remote_uci)
    local rem_exps = remote_uci:get_all(config)
    local loc_exps = local_uci:get_all(config)

    -- Insert and update experiments found in remote config file
    for ename,exp in pairs(rem_exps) do
        if loc_exps[ename] == nil then
            local_uci:set(config, ename, 'experiment')
            local_uci:set(config, ename, 'available', UCI_TRUE)
            local_uci:set(config, ename, 'installed', UCI_FALSE)
            pdebug("Experiment %q added to local experiment set.\n", ename)
        else
            pdebug("Updating local experiment %q.\n", ename)
        end
        local_uci:set(config, ename, 'description', exp.description)
        local_uci:set(config, ename, 'display_name', exp.display_name)
        local_uci:set(config, ename, 'packages', exp.packages)
    end

    -- Remove experiments not found in remote config file
    local exps_to_delete = {}
    for ename,exp in pairs(loc_exps) do
        if rem_exps[ename] == nil then
            local_uci:set(config, ename, 'available', UCI_FALSE)
            if not uci_bool(local_uci:get(config, ename, 'installed')) then
                exps_to_delete[#exps_to_delete + 1] = ename
            end
        end
    end
    for i,ename in pairs(exps_to_delete) do
        local_uci:delete(config, ename)
        pdebug("Experiment %q deleted from local experiment set.\n", ename)
    end
end


function uci_bool(s)
    -- interpret the many ways true or false can be expressed in UCI.
    local retval = nil
    s = s:lower()
    if s == 'true' or s == '1' or s == 'yes' then
        retval = true
    elseif s == 'false' or s == '0' or s == 'no' then
        retval = false
    end
    return retval
end


function pdebug(s, ...)
    if DEBUG ~= nil and DEBUG == true then
        io.stderr:write(string.format(s, unpack(arg)))
    end
end


------------------------------------------------------------------------------
-- TESTING STUFF
------------------------------------------------------------------------------
function init_be_remote_uci(uci_cursor, filename)
    -- initialize remote bismark-experiments config file with reasonable values
    local success = true
    local config_name = filename
    local sec_name = 'wifi_beacons'
    success = success and uci_cursor:set(config_name, sec_name, 'experiment')
    success = success and uci_cursor:set(config_name, sec_name,
            'display_name', 'Wifi Beacons')
    success = success and uci_cursor:set(config_name, sec_name, 'description',
            'Wifi Beacons collects data about the devices connected to your ' ..
            'BISmark router over wireless, as well as the presence of other ' ..
            'nearby wireless access points. <b>Wifi Beacons does not ' ..
            'collect the contents of your network traffic.</b>')
    success = success and uci_cursor:set(config_name, sec_name, 'packages',
            {'wifi_beacons-tmpfs',
             'bismark-data-uploader'})
    if success then
        uci_cursor:commit(config_name)
    else
        print("failure")
    end
end


function init_be_local_uci(uci_cursor)
    -- initialize local bismark-experiments config file with reasonable values
    local success = true
    local config_name = 'bismark-experiments'
    local sec_name = 'wifi_beacons'
    init_be_remote_uci(uci_cursor, config_name)
    success = success and uci_cursor:set(config_name, sec_name,
            'installed', UCI_TRUE)
    success = success and uci_cursor:set(config_name, sec_name,
            'available', UCI_TRUE)
    if success then
        uci_cursor:commit(config_name)
    else
        print("failure")
    end
end


------------------------------------------------------------------------------
-- EXECUTE THIS SCRIPT
------------------------------------------------------------------------------
return main(arg)