[docs] Move caching and security notes from README

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Nguyễn Gia Phong 2020-09-08 22:58:35 +07:00
parent be0eb4870d
commit 901e03f39f
5 changed files with 67 additions and 66 deletions

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@ -466,71 +466,6 @@ vicious.register. Your function can accept `format` and `warg`
arguments, just like workers.
## <a name="power"></a>Power and Caching
When a lot of widgets are in use they, and awesome, can generate a lot
of wake-ups and also be very expensive for system resources. This is
especially important when running on battery power. It was a big
problem with awesome v2 and widgets that used shell scripts to gather
data, and with widget libraries written in languages like Ruby.
Lua is an extremely fast and efficient programming language, and
Vicious takes advantage of that. But suspending Vicious widgets is one
way to prevent them from draining your battery, despite that.
Update intervals also play a big role, and you can save a lot of power
with a smart approach. Don't use intervals like: 5, 10, 30, 60, … to
avoid harmonics. If you take the 60-second mark as an example, all of
your widgets would be executed at that point. Instead think about
using only prime numbers, in that case you will have only a few
widgets executed at any given time interval. When choosing intervals
also consider what a widget actually does. Some widget types read
files that reside in memory, others call external utilities and some,
like the mbox widget, read big files.
Vicious can also cache values returned by widget types. Caching
enables you to have multiple widgets using the same widget type. With
caching its worker function gets executed only once - which is also
great for saving power.
* Some widget types keep internal data and if you call one multiple times
without caching, the widget that executes it first would modify stored
values. This can lead to problems and give you inconsistent data. Remember
it for widget types like CPU and Network usage, which compare the old set of
data with the new one to calculate current usage.
* Widget types that require a widget argument to be passed should be handled
carefully. If you are requesting information for different devices then
caching should not be used, because you could get inconsistent data.
## Security
At the moment only one widget type (Gmail) requires auth. information
in order to get to the data. In the future there could be more, and
you should give some thought to the issue of protecting your data. The
Gmail widget type by default stores login information in the ~/.netrc
file, and you are advised to make sure that file is only readable by
the owner. Other than that we can not force all users to conform to
one standard, one way of keeping it secure, like in some keyring.
First let's clear why we simply don't encrypt the login information
and store it in ciphertext. By exposing the algorithm anyone can
reverse the encryption steps. Some claim even that's better than
plaintext but it's just security trough obscurity.
Here are some ideas actually worth your time. Users that have KDE (or
parts of it) installed could store their login information into the
Kwallet service and request it via DBus from the widget type. It can
be done with tools like `dbus-send` and `qdbus`. The Gnome keyring
should support the same, so those with parts of Gnome installed could
use that keyring.
Users of GnuPG (and its agent) could consider encrypting the netrc
file with their GPG key. Trough the GPG Passphrase Agent they could
then decrypt the file transparently while their session is active.
## Usage examples
Start with a simple widget, like `date`. Then build your setup from

37
docs/source/caching.rst Normal file
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@ -0,0 +1,37 @@
.. _caching:
Power and Caching
=================
When a lot of widgets are in use they, and awesome, can generate a lot
of wake-ups and also be very expensive for system resources. This is
especially important when running on battery power. It was a big problem
with awesome v2 and widgets that used shell scripts to gather data,
and with widget libraries written in languages like Ruby.
Lua is an extremely fast and efficient programming language, and Vicious
takes advantage of that. But suspending Vicious widgets is one way
to prevent them from draining your battery, despite that.
Update intervals also play a big role, and you can save a lot of power
with a smart approach. Don't use intervals like: 5, 10, 30, 60, etc.
to avoid harmonics. If you take the 60-second mark as an example,
all of your widgets would be executed at that point. Instead think about
using only prime numbers, in that case you will have only a few widgets
executed at any given time interval. When choosing intervals also consider
what a widget actually does. Some widget types read files that reside
in memory, others call external utilities and some, like the mbox widget,
read big files.
Vicious can also cache values returned by widget types. Caching enables you
to have multiple widgets using the same widget type. With caching its worker
function gets executed only once---which is also great for saving power.
* Some widget types keep internal data and if you call one multiple times
without caching, the widget that executes it first would modify stored values.
This can lead to problems and give you inconsistent data. Remember it
for widget types like CPU and Network usage, which compare the old set
of data with the new one to calculate current usage.
* Widget types that require a widget argument to be passed should be
handled carefully. If you are requesting information for different devices
then caching should not be used, because you could get inconsistent data.

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@ -20,6 +20,8 @@ Table of Contents
usage-lua
usage-awesome
caching
security
copying
See Also

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docs/source/security.rst Normal file
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@ -0,0 +1,27 @@
Security Notes
==============
At the moment only one widget type (Gmail) requires
authentication information in order to get to the data.
In the future there could be more, and you should give some thought
to the issue of protecting your data. The Gmail widget type by default
stores login information in the ``~/.netrc`` file, and you are advised
to make sure that file is only readable by the owner. Other than that
we can not force all users to conform to one standard,
one way of keeping it secure, like in some keyring.
First let's clear why we simply don't encrypt the login information
and store it in ciphertext. By exposing the algorithm anyone can
reverse the encryption steps. Some claim even that's better than
plaintext but it's just security through obscurity.
Here are some ideas actually worth your time. Users that have KDE
(or parts of it) installed could store their login information into
the Kwallet service and request it via DBus from the widget type.
It can be done with tools like ``dbus-send`` and ``qdbus``.
The Gnome keyring should support the same, so those with parts of Gnome
installed could use that keyring.
Users of GnuPG (and its agent) could consider encrypting the netrc file
with their GPG key. Through the GPG Passphrase Agent they could then
decrypt the file transparently while their session is active.

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@ -46,7 +46,7 @@ Once you create a widget (a textbox, graph or a progressbar) call
``interval``
Number of seconds between updates of the widget (default: 2).
Read section [Power and Caching](#power) for more information.
Read section :ref:`caching` for more information.
``warg``
Arguments to be passed to widget types, e.g. the battery ID.