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[add blog post] Developing in Linux containers [202006]
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
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Markus Heiser
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@ -6,6 +6,7 @@ Blog
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:maxdepth: 2
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:caption: Contents
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lxcdev-202006
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python3
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admin
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intro-offline
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413
docs/blog/lxcdev-202006.rst
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413
docs/blog/lxcdev-202006.rst
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.. _blog-lxcdev-202006:
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=======================================
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Developing in Linux containers [202006]
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=======================================
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.. _LXC: https://linuxcontainers.org/lxc/introduction/
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.. sidebar:: Audience
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This blog post is written for experienced admins and developers / readers
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should have a serious meaning about: *distributed*, *merge* and *linux
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container*.
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.. contents:: Contents
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:depth: 2
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:local:
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:backlinks: entry
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In PR :PR:`1803` we added a lot of scripts to Searx's boilerplate. In this blog
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post I will show you, how you can make use of them in *distributed and
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heterogeneous development cycles* (TL;DR; jump to the :ref:`blog-lxcdev-202006
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abstract`).
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Motivation
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==========
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Normally in our development cycle, we edit the sources and run some test and/or
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builds by using ``make`` before we commit. This cycle is simple and perfect but
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might fail in some aspects we should not overlook.
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The environment in which we run all our development processes matters!
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The :ref:`makefile` and the :ref:`make pyenv` encapsulate a lot for us, but they
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do not have access to all prerequisites. For example, there may have
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dependencies on packages that are installed on the developer's desktop, but
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usually are not preinstalled on a server or client system. Another examples
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are; settings have been made to the software on the developer's host that would
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never be set on a *production* system.
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*Linux Containers* (LXC_) are isolate environments and not to mix up on
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developer's all the prerequisites of all the projects he contribute to, is
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always a good choice.
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The scripts from PR :PR:`1803` can divide in those to install and maintain
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software:
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- :ref:`searx.sh`
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- :ref:`filtron.sh`
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- :ref:`morty.sh`
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and the script :ref:`lxc.sh`, with we can scale our installation, maintenance or
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even development tasks over a stack of containers, what we call: *Searx's lxc
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suite*.
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Gentlemen, start your engines!
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==============================
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.. _LXD: https://linuxcontainers.org/lxd/introduction/
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.. _archlinux: https://www.archlinux.org/
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Before you can start with containers, you need to install and initiate LXD_
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once:
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ snap install lxd
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$ lxd init --auto
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And you need to clone from origin or if you have your own fork, clone from your
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fork:
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ cd ~/Downloads
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$ git clone https://github.com/asciimoo/searx.git
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$ cd searx
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The :ref:`lxc-searx.env` consists of several images, see ``export
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LXC_SUITE=(...`` near by :origin:`utils/lxc-searx.env#L19`. For this blog post
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we exercise on a archlinux_ image. The container of this image is named
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``searx-archlinux``. Lets build the container, but be sure that this container
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does not already exists, so first lets remove possible old one:
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh remove searx-archlinux
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$ sudo -H ./utils/lxc.sh build searx-archlinux
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.. sidebar:: The ``searx-archlinux`` container
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is the base of all our exercises here.
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In this container we install all services :ref:`including searx, morty & filtron
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<lxc.sh install suite>` in once:
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh install suite searx-archlinux
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To proxy HTTP from filtron and morty in the container to the outside of the
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container, install nginx into the container. Once for the bot blocker filtron:
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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./utils/filtron.sh nginx install
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...
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INFO: got 429 from http://10.174.184.156/searx
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and once for the content sanitizer (content proxy morty):
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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./utils/morty.sh nginx install
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...
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INFO: got 200 from http://10.174.184.156/morty/
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.. sidebar:: Fully functional searx suite
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From here on you have a fully functional searx suite running with bot blocker
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(filtron) and Web content sanitizer (content proxy morty) needed for a
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*privacy protecting* search engine.
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On your system, the IP of your ``searx-archlinux`` container differs from
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http://10.174.184.156/searx, just open the URL reported in your installation
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protocol in your WEB browser from the desktop to test the instance from outside
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of the container.
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In such a searx suite admins can maintain and access the debug log of the
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different services quite easy.
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.. _working in containers:
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In containers, work as usual
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============================
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Usually you open a root-bash using ``sudo -H bash``. In case of LXC containers
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open the root-bash in the container using ``./utils/lxc.sh cmd
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searx-archlinux``:
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux bash
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INFO: [searx-archlinux] bash
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[root@searx-archlinux searx]# pwd
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/share/searx
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The prompt ``[root@searx-archlinux ...]`` signals, that you are the root user in
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the searx-container. To debug the running searx instance use:
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.. tabs::
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.. group-tab:: root@searx-archlinux
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.. code:: sh
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$ ./utils/searx.sh inspect service
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...
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use [CTRL-C] to stop monitoring the log
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...
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Back in the browser on your desktop open the service http://10.174.184.156/searx
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and run your application tests while the debug log is shown in the terminal from
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above. You can stop monitoring using ``CTRL-C``, this also disables the *"debug
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option"* in searx's settings file and restarts the searx uwsgi application. To
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debug services from filtron and morty analogous use:
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.. tabs::
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.. group-tab:: root@searx-archlinux
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.. code:: sh
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$ ./utils/filtron.sh inspect service
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$ ./utils/morty.sh inspect service
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Another point we have to notice is that each service (:ref:`searx <searx.sh>`,
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:ref:`filtron <filtron.sh>` and :ref:`morty <morty.sh>`) runs under dedicated
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system user account with the same name (compare :ref:`create searx user`). To
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get a shell from theses accounts, simply call one of the scripts:
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.. tabs::
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.. group-tab:: root@searx-archlinux
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.. code:: sh
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$ ./utils/searx.sh shell
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$ ./utils/filtron.sh shell
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$ ./utils/morty.sh shell
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To get in touch, open a shell from the service user (searx@searx-archlinux):
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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./utils/searx.sh shell
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// exit with [CTRL-D]
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(searx-pyenv) [searx@searx-archlinux ~]$ ...
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The prompt ``[searx@searx-archlinux]`` signals that you are logged in as system
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user ``searx`` in the ``searx-archlinux`` container and the python *virtualenv*
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``(searx-pyenv)`` environment is activated.
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.. tabs::
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.. group-tab:: searx@searx-archlinux
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.. code:: sh
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(searx-pyenv) [searx@searx-archlinux ~]$ pwd
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/usr/local/searx
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Wrap production into developer suite
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====================================
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In this section we will see how to change the *"Fully functional searx suite"*
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from a LXC container (which is quite ready for production) into a developer
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suite. For this, we have to keep an eye on the :ref:`installation basic`:
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- searx setup in: ``/etc/searx/settings.yml``
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- searx user's home: ``/usr/local/searx``
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- virtualenv in: ``/usr/local/searx/searx-pyenv``
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- searx software in: ``/usr/local/searx/searx-src``
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The searx software is a clone of the ``GIT_URL`` (see :ref:`makefile setup`) and
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the working tree is checked out from the ``GIT_BRANCH``. With the use of the
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:ref:`searx.sh` the searx service was installed as :ref:`uWSGI application
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<searx uwsgi>`. To maintain this service, we can use ``systemctl`` (compare
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:ref:`service architectures on distributions <uwsgi configuration>`).
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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systemctl stop uwsgi@searx
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With the command above, we stopped the searx uWSGI-App in the archlinux
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container.
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The uWSGI-App for the archlinux dsitros is configured in
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:origin:`utils/templates/etc/uwsgi/apps-archlinux/searx.ini`, from where at
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least you should attend the settings of ``uid``, ``chdir``, ``env`` and
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``http``::
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env = SEARX_SETTINGS_PATH=/etc/searx/settings.yml
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http = 127.0.0.1:8888
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chdir = /usr/local/searx/searx-src/searx
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virtualenv = /usr/local/searx/searx-pyenv
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pythonpath = /usr/local/searx/searx-src
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If you have read the :ref:`"Good to know section" <lxc.sh>` you remember, that
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each container shares the root folder of the repository and the command
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``utils/lxc.sh cmd`` handles relative path names **transparent**. To wrap the
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searx installation into a developer one, we simple have to create a smylink to
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the **transparent** reposetory from the desktop. Now lets replace the
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repository at ``searx-src`` in the container with the working tree from outside
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of the container:
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.. tabs::
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.. group-tab:: container becomes a developer suite
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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mv /usr/local/searx/searx-src /usr/local/searx/searx-src.old
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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ln -s /share/searx/ /usr/local/searx/searx-src
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Now we can develop as usual in the working tree of our desktop system. Every
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time the software was changed, you have to restart the searx service (in the
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conatiner):
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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systemctl restart uwsgi@searx
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Remember: :ref:`working in containers` .. here are just some examples from my
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daily usage:
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.. tabs::
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.. group-tab:: desktop
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To *inspect* the searx instance (already described above):
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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./utils/searx.sh inspect service
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Run :ref:`makefile`, e.g. to test inside the container:
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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make test
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To install all prerequisites needed for a :ref:`buildhosts`:
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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./utils/searx.sh install buildhost
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To build the docs on a buildhost :ref:`buildhosts`:
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.. code:: sh
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$ sudo -H ./utils/lxc.sh cmd searx-archlinux \
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make docs
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.. _blog-lxcdev-202006 abstract:
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Abstract
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========
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We build up a fully functional searx suite in a archlinux container:
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.. code:: sh
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$ sudo -H ./utils/lxc.sh install suite searx-archlinux
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To access HTTP from the desktop we installed nginx for the services inside the
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conatiner:
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.. tabs::
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.. group-tab:: [root@searx-archlinux]
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.. code:: sh
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$ ./utils/filtron.sh nginx install
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$ ./utils/morty.sh nginx install
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To wrap the suite into a developer one, we created a symbolic link to the
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repository which is shared **transparent** from the desktop's file system into
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the container :
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.. tabs::
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.. group-tab:: [root@searx-archlinux]
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.. code:: sh
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$ mv /usr/local/searx/searx-src /usr/local/searx/searx-src.old
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$ ln -s /share/searx/ /usr/local/searx/searx-src
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$ systemctl restart uwsgi@searx
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To get remarks from the suite of the archlinux container we can use:
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.. tabs::
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.. group-tab:: desktop
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.. code:: sh
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$ sudo -H ./utils/lxc.sh show suite searx-archlinux
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...
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[searx-archlinux] INFO: (eth0) filtron: http://10.174.184.156:4004/ http://10.174.184.156/searx
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[searx-archlinux] INFO: (eth0) morty: http://10.174.184.156:3000/
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[searx-archlinux] INFO: (eth0) docs-live: http://10.174.184.156:8080/
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[searx-archlinux] INFO: (eth0) IPv6: http://[fd42:573b:e0b3:e97e:216:3eff:fea5:9b65]
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...
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@ -47,9 +47,9 @@ one**::
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*Good to know ...*
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Eeach container shares the root folder of the repository and the
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command ``utils/lxc.sh cmd`` **handles relative path names transparent**,
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compare output of::
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Each container shares the root folder of the repository and the command
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``utils/lxc.sh cmd`` **handles relative path names transparent**, compare output
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of::
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$ sudo -H ./utils/lxc.sh cmd -- ls -la Makefile
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...
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@ -66,6 +66,7 @@ If there comes the time you want to **get rid off all** the containers and
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$ sudo -H ./utils/lxc.sh remove
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$ sudo -H ./utils/lxc.sh remove images
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.. _lxc.sh install suite:
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Install suite
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=============
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Reference in New Issue
Block a user