Stacks (Hanging)¶

Topics¶

DBus (New Topic)¶

Principles
- commandline interface
- system vs. session/user
- XML service definitions
pydbus
openheating

Blog post on fixing the import pydbus error

$ ./unittests/run.py
Traceback (most recent call last):
  File "/home/jfasch/work/openheating/./unittests/run.py", line 8, in <module>
    from oh_tests.dbus.easysuite import suite as oh_dbus_easysuite
  File "/home/jfasch/work/openheating/unittests/oh_tests/dbus/easysuite.py", line 1, in <module>
    from .easysuite_error import suite as error_suite
  File "/home/jfasch/work/openheating/unittests/oh_tests/dbus/easysuite_error.py", line 2, in <module>
    from openheating.dbus.error import DBusHeatingError
  File "./unittests/../openheating/dbus/error.py", line 5, in <module>
    import gi.repository
ModuleNotFoundError: No module named 'gi'

Note

use interactive interpreter for that

Research:

Where does gi come from? See below, PyGObject.
Why is there no dependency on PyGObject from pydbus?

$ pip install PyGObject
Collecting PyGObject
  Using cached PyGObject-3.40.1.tar.gz (714 kB)
  Installing build dependencies ... error
  ERROR: Command errored out with exit status 1:
   command: /home/jfasch/venv/openheating/bin/python /tmp/pip-standalone-pip-ss_9wmug/__env_pip__.zip/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-9lrqmi4l/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- setuptools wheel pycairo
       cwd: None
  Complete output (38 lines):
  Collecting setuptools
    Using cached setuptools-57.0.0-py3-none-any.whl (821 kB)
  Collecting wheel
    Using cached wheel-0.36.2-py2.py3-none-any.whl (35 kB)
  Collecting pycairo
    Using cached pycairo-1.20.1.tar.gz (344 kB)
    Installing build dependencies: started
    Installing build dependencies: finished with status 'done'
    Getting requirements to build wheel: started
    Getting requirements to build wheel: finished with status 'done'
      Preparing wheel metadata: started
      Preparing wheel metadata: finished with status 'done'
  Building wheels for collected packages: pycairo
    Building wheel for pycairo (PEP 517): started
    Building wheel for pycairo (PEP 517): finished with status 'error'
    ERROR: Command errored out with exit status 1:
     command: /home/jfasch/venv/openheating/bin/python /tmp/tmpabab356k_in_process.py build_wheel /tmp/tmpt1yod7mc
         cwd: /tmp/pip-install-o4u45fjc/pycairo_33865a19ad6b4a719885f07926efe16d
    Complete output (15 lines):
    running bdist_wheel
    running build
    running build_py
    creating build
    creating build/lib.linux-x86_64-3.9
    creating build/lib.linux-x86_64-3.9/cairo
    copying cairo/__init__.py -> build/lib.linux-x86_64-3.9/cairo
    copying cairo/__init__.pyi -> build/lib.linux-x86_64-3.9/cairo
    copying cairo/py.typed -> build/lib.linux-x86_64-3.9/cairo
    running build_ext
    Package cairo was not found in the pkg-config search path.
    Perhaps you should add the directory containing `cairo.pc'
    to the PKG_CONFIG_PATH environment variable
    Package 'cairo', required by 'virtual:world', not found
    Command '['pkg-config', '--print-errors', '--exists', 'cairo >= 1.15.10']' returned non-zero exit status 1.
    ----------------------------------------
    ERROR: Failed building wheel for pycairo
  Failed to build pycairo
  ERROR: Could not build wheels for pycairo which use PEP 517 and cannot be installed directly

Install cairo headers and stuff
```
$ sudo dnf install cairo-devel
```
Next: gobject-introspection-devel

$ pip install PyGObject
Collecting PyGObject
    Using cached PyGObject-3.40.1.tar.gz (714 kB)
    Installing build dependencies ... done
    Getting requirements to build wheel ... done
      Preparing wheel metadata ... done
  Collecting pycairo>=1.16.0
    Using cached pycairo-1.20.1-cp39-cp39-linux_x86_64.whl
  Building wheels for collected packages: PyGObject
    Building wheel for PyGObject (PEP 517) ... error
    ERROR: Command errored out with exit status 1:
     command: /home/jfasch/venv/openheating/bin/python /home/jfasch/venv/openheating/lib64/python3.9/site-packages/pip/_vendor/pep517/in_process/_in_process.py build_wheel /tmp/tmpf2wjv23h
         cwd: /tmp/pip-install-4rtfumdz/pygobject_beef4432e2454eb0b7facc57fadf42b8
    Complete output (44 lines):
    running bdist_wheel
    running build
    running build_py
    creating build
    creating build/lib.linux-x86_64-3.9
    creating build/lib.linux-x86_64-3.9/pygtkcompat
    copying pygtkcompat/pygtkcompat.py -> build/lib.linux-x86_64-3.9/pygtkcompat
    copying pygtkcompat/generictreemodel.py -> build/lib.linux-x86_64-3.9/pygtkcompat
    copying pygtkcompat/__init__.py -> build/lib.linux-x86_64-3.9/pygtkcompat
    creating build/lib.linux-x86_64-3.9/gi
    copying gi/types.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/pygtkcompat.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/module.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/importer.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/docstring.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/_signalhelper.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/_propertyhelper.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/_ossighelper.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/_option.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/_gtktemplate.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/_error.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/_constants.py -> build/lib.linux-x86_64-3.9/gi
    copying gi/__init__.py -> build/lib.linux-x86_64-3.9/gi
    creating build/lib.linux-x86_64-3.9/gi/repository
    copying gi/repository/__init__.py -> build/lib.linux-x86_64-3.9/gi/repository
    creating build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/keysyms.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/__init__.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/Pango.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/Gtk.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/Gio.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/GdkPixbuf.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/Gdk.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/GObject.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/GLib.py -> build/lib.linux-x86_64-3.9/gi/overrides
    copying gi/overrides/GIMarshallingTests.py -> build/lib.linux-x86_64-3.9/gi/overrides
    running build_ext
    Package gobject-introspection-1.0 was not found in the pkg-config search path.
    Perhaps you should add the directory containing `gobject-introspection-1.0.pc'
    to the PKG_CONFIG_PATH environment variable
    Package 'gobject-introspection-1.0', required by 'virtual:world', not found
    Command '('pkg-config', '--print-errors', '--exists', 'gobject-introspection-1.0 >= 1.56.0')' returned non-zero exit status 1.

    Try installing it with: 'sudo dnf install gobject-introspection-devel'
    ----------------------------------------
    ERROR: Failed building wheel for PyGObject
  Failed to build PyGObject
  ERROR: Could not build wheels for PyGObject which use PEP 517 and cannot be installed directly

Fix it

$ sudo dnf install gobject-introspection-devel

Next, Gosh! cairo-gobject-devel

$ pip install PyGObject
Collecting PyGObject
  Using cached PyGObject-3.40.1.tar.gz (714 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Collecting pycairo>=1.16.0
  Using cached pycairo-1.20.1-cp39-cp39-linux_x86_64.whl
Building wheels for collected packages: PyGObject
  Building wheel for PyGObject (PEP 517) ... error
  ERROR: Command errored out with exit status 1:
   command: /home/jfasch/venv/openheating/bin/python /home/jfasch/venv/openheating/lib64/python3.9/site-packages/pip/_vendor/pep517/in_process/_in_process.py build_wheel /tmp/tmp56g_ixbz
       cwd: /tmp/pip-install-bvay4iv4/pygobject_6777f13e15934fb2b13139399b143557
  Complete output (44 lines):
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.linux-x86_64-3.9
  creating build/lib.linux-x86_64-3.9/pygtkcompat
  copying pygtkcompat/pygtkcompat.py -> build/lib.linux-x86_64-3.9/pygtkcompat
  copying pygtkcompat/generictreemodel.py -> build/lib.linux-x86_64-3.9/pygtkcompat
  copying pygtkcompat/__init__.py -> build/lib.linux-x86_64-3.9/pygtkcompat
  creating build/lib.linux-x86_64-3.9/gi
  copying gi/types.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/pygtkcompat.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/module.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/importer.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/docstring.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/_signalhelper.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/_propertyhelper.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/_ossighelper.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/_option.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/_gtktemplate.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/_error.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/_constants.py -> build/lib.linux-x86_64-3.9/gi
  copying gi/__init__.py -> build/lib.linux-x86_64-3.9/gi
  creating build/lib.linux-x86_64-3.9/gi/repository
  copying gi/repository/__init__.py -> build/lib.linux-x86_64-3.9/gi/repository
  creating build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/keysyms.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/__init__.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/Pango.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/Gtk.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/Gio.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/GdkPixbuf.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/Gdk.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/GObject.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/GLib.py -> build/lib.linux-x86_64-3.9/gi/overrides
  copying gi/overrides/GIMarshallingTests.py -> build/lib.linux-x86_64-3.9/gi/overrides
  running build_ext
  Package cairo-gobject was not found in the pkg-config search path.
  Perhaps you should add the directory containing `cairo-gobject.pc'
  to the PKG_CONFIG_PATH environment variable
  Package 'cairo-gobject', required by 'virtual:world', not found
  Command '('pkg-config', '--print-errors', '--exists', 'cairo-gobject >= 0')' returned non-zero exit status 1.

  Try installing it with: 'sudo dnf install cairo-gobject-devel'
  ----------------------------------------
  ERROR: Failed building wheel for PyGObject
Failed to build PyGObject
ERROR: Could not build wheels for PyGObject which use PEP 517 and cannot be installed directly

Fix
```
$ sudo dnf install cairo-gobject-devel
```
Finally, yay!
```
$ pip install PyGObject
```
TODO: executive summary

$ dnf install all packages

Perturb Encoding ¶

Rename it so we can fix all referers. Split string explanation out of legacy “encoding” topic.
Create “legacy” group and move old stuff there.
Move new encoding into basic. Better yet, create one new group ‘special’ (“other python core topics”)

Context Managers (Slideshow)¶

Bring pseudo code in the slideshow. What is solved?

ABC (new Topic)¶

There was a live-hacking session about interface vs. duck typing (in Gmunden I belive). Error at instantiate (abc) rather than use: as early as possible).

Finish Meta/SEO and Stuff¶

todo
- style
  - <li> spacing
  - nested lists: space before less than after
  - /trainings/index.rst: only overview over topics, for example “C” (-> C1,2,3), “Sysprog” -> sysprog*, “Embedded” -> sysprog-embedded, raspi-hands-on, “misc” -> kernel
- title page: https://www.w3schools.com/howto/howto_css_image_transparent.asp
- courses
  - meta += see also (bisher gehaltene, unterlagen)
  - schulungen zentraler
    - auf der titelseite in die mitte
    - courses/index knackiger
    - image mit text: https://www.w3schools.com/howto/howto_css_image_transparent.asp
  - records
    - https://www.w3schools.com/howto/howto_js_read_more.asp
    - material in subdir (gegen menu clutter)
- 404 not found -> link to co.at oder so
seo/meta
- Low prio
  - courses/booking.rst
  - courses/programming-languages/index.rst
  - courses/material/sysprog/signals-slides.rst
  - courses/material/sysprog/ipc-slides.rst
- blog/2010/07/beagleboard-how-to-repair-nand-also-known-as-40w.rst
- blog/index.rst
- blog/2020/03/custom-domain-gh-pages.rst
- blog/2020/03/sphinx-gh-pages.rst
- blog/2020/02/fedora-kernel-build.rst
- blog/2012/04/Why-ps-sucks.rst
- blog/2011/01/saving-solid-state-disk-life--gentoo.rst
- blog/2011/01/porting-to-linux-there-s-always-a-better-way.rst
- index.rst
- about/myself/index.rst
- about/myself/cv-de.rst
- about/myself/projects-de.rst
- about/myself/skills-de.rst
- about/myself/contact.rst
- about/site/index.rst
- about/site/recipes.rst
- about/site/work-in-progress/layout-test.rst
- about/site/work-in-progress/todo-misc.rst
- about/site/work-in-progress/index.rst
- about/site/work-in-progress/stacks.rst
- about/site/work-in-progress/seo.rst
- about/site/work-in-progress/blog-queue/index.rst
- about/site/work-in-progress/blog-queue/github-pages-custom-domains-ssl-bad-certificate.rst
- about/site/work-in-progress/s5/tests/test-slides.rst
- about/site/work-in-progress/s5/tests/index.rst
- about/site/work-in-progress/s5/index.rst
- courses/linux/070-sysprog-fortgeschrittenes.rst
- courses/linux/700-kettner-lfs-descr.rst
- courses/linux/050-sysprog-network.rst
- courses/linux/200-raspi-hands-on.rst
- courses/linux/index.rst
- courses/linux/080-sysprog-embedded.rst
- courses/linux/020-sysprog-basics.rst
- courses/linux/060-sysprog-multithreading.rst
- courses/linux/_hidden/kettner-lfs-2013-09-16.rst
- courses/linux/010-linux-basics.rst
- courses/linux/190-kernel-programming-basics.rst
- courses/records/2020-01-10/Proposal.rst
- courses/records/2020-01-10/index.rst
- courses/records/2013-10-01/index.rst
- courses/records/index.rst
- courses/records/2019-11-12/index.rst
- courses/records/2020-03-30/index.rst
- courses/records/2019-10-28/index.rst
- courses/index.rst
- courses/programming-misc/index.rst
- courses/programming-misc/020-make.rst
- courses/programming-misc/030-svn.rst
- courses/programming-misc/050-design-patterns.rst
- courses/programming-misc/040-unittests.rst