accessing recources when compiling QT application with Bazel - c++

Question

I'm using Bazel to compile a Qt application (https://github.com/bbreslauer/qt-bazel-example) that is using shaders defined in a qrc file.
When I'm trying to access the resource file, it is not available (as I did not connect the qrc file to the compilation).
How can I define the qrc file content in the build?
UPDATE
following the response by #ypnos, I'm trying to add a macro to my qt.bzl file. I would like the macro to recieve a list of files as an argument, create the (temporary) qrc file, and run the rcc command.
I am currently struggling with:
running a python script in the bzl file is not as straightforward as I though. It cannot generate a file ("open" is undefined). Is it possible? if yes how (see example below)
even with a given qrc file, I cant get the command to work, I guess i'm doing somthing wrong with the command line arguments but I cant find refrence/manual for that
this is what I got so far(my qt.bzl file)
...
def qt_resource(name,file_list, **kwargs):
## following doesnt work inside the bzl file:
# fid = open('%s.qrc' % name, 'w')
# fid.write("<RCC>\n")
# fid.write("\t<qresource prefix=\"/%s\">\n" % name)
# for x in file_list:
# fid.write("\t\t<file>%s</file>\n" % x)
# fid.write("\t</qresource>\n")
# fid.write("</RCC>\n")
# fid.close()
native.genrule(
name = "%s_res" % name,
outs = ["rcc_%s.cpp" % name],
cmd = "rcc %s.qrc -o $#/rcc_%s.cpp"%(name,name) ,
)
srcs = [":rcc_%s.cpp" % name]
native.cc_library(
name = name,
srcs = srcs,
hdrs = [],
deps = [],
**kwargs
)

Answer 1

It seems the bazel example that you are using does not come with support for qrc (it only does moc and ui files).1
QRC files need to be transformed into C++ sources using rcc and then compiled.2 The concept is similar to the one of .ui files which are converted to headers.
Maybe you can patch qt.bzl to add that functionality.