14 Using a Python Development Shell

Similar to working within a development shell as described in the previous section, you can also spawn and work within an interactive Python development shell. When debugging certain commands or even when just editing packages, pydevshell can be a useful tool. When you invoke the pydevshell task, all tasks up to and including do_patch are run for the specified target. Then a new terminal is opened. Additionally, key Python objects and code are available in the same way they are to BitBake tasks, in particular, the data store ‘d’. So, commands such as the following are useful when exploring the data store and running functions:

pydevshell> d.getVar("STAGING_DIR")
'/media/build1/poky/build/tmp/sysroots'
pydevshell> d.getVar("STAGING_DIR", False)
'${TMPDIR}/sysroots'
pydevshell> d.setVar("FOO", "bar")
pydevshell> d.getVar("FOO")
'bar'
pydevshell> d.delVar("FOO")
pydevshell> d.getVar("FOO")
pydevshell> bb.build.exec_func("do_unpack", d)
pydevshell>

See the “Functions You Can Call From Within Python” section in the BitBake User Manual for details about available functions.

The commands execute just as if the OpenEmbedded build system were executing them. Consequently, working this way can be helpful when debugging a build or preparing software to be used with the OpenEmbedded build system.

Here is an example that uses pydevshell on a target named matchbox-desktop:

$ bitbake matchbox-desktop -c pydevshell

This command spawns a terminal and places you in an interactive Python interpreter within the OpenEmbedded build environment. The OE_TERMINAL variable controls what type of shell is opened.

When you are finished using pydevshell, you can exit the shell either by using Ctrl+d or closing the terminal window.