Re: GNU Radio 3.9 gr_modtool problem

[Ryan Volz]

Hi Boris,

On 5/16/21 7:20 PM, Boris Marjanovic wrote:
> I understand that the original issue was resolved. But I have the same problem 
> with a different setup.
>
> I installed (did ot build it myself) gnuradio 3.9. on Ubuntu 20.02.2 using 
> ppa:gnuradio/gnuradio-releases with no issues. The companion seems to work 
> fine. Similar to above, though, I can not create new module using modtool 'out 
> of the box'.
> Running gr_modtool fails
> $ gr_modtool newmod temp
> ModToolException: Could not find gr-newmod source dir.
> Interestingly, running config info returns prefix '/.'
> $ gnuradio-config-info --prefix
> /.
> This would explain why gr.prefix() which is imported via 'form gnuradio import 
> gr' returns the string that creates an incorrect path to search for templates 
> and later to find clang-format.conf file.

This is definitely strange and points to a problem with the package build or 
with the prefix handling in gnuradio-runtime. I would expect 
`gnuradio-config-info --prefix` to return '/usr' or '/usr/.' in this case. 
Looking at the PPA package build log didn't turn up anything questionable to 
me, so I'm at a loss.

> I think there might be an issue with the installation package. As far as I can tell, 
> (I'm 'advanced beginner' in python, so nothing is certain) that comes from shared 
> library 
> /usr/lib/python3/dist-packages/gnuradio/gr/gr_python.cpython-38-x86_64-linux-gnu.so 
> <http://gr_python.cpython-38-x86_64-linux-gnu.so>
> Having the correct path in /etc/gnuradio/conf.d/modtool.conf makes no 
> difference. I copied the file to ~/.gnuradio/config.conf  but still did not 
> work. For some reason it seems these files are not checked for the path.
> It seems gr_modtool was re-written in 3.9 (maybe 3.8) to use click. The code 
> shows there is now a parameter for a newmod option 'srcdir'. If srcdir is 
> provided, the module seems to be created,
> $ gr_modtool newmod --srcdir /usr/share/gnuradio/modtool/templates/gr-newmod 
> temp
> Creating out-of-tree module in ./gr-temp...
> Failed to copy .clang-format: [Errno 2] No such file or directory: 
> '/./share/gnuradio/clang-format.conf'
> Done.
> Use 'gr_modtool add' to add a new block to this currently empty module.
>
> Note that the srcdir provided in the command is the same as the value in the 
> config file. There is still a failure because file clang-format.conf can not be 
> found. The reason is the same as before - gr.prefix() returns incorrect value. 
> But it seems to be 'warning level' since the module scaffolding seems to be in 
> place and blocks can be added. I have not tried compiling them yet though.
> The workaround (would not call it a fix) is to modify lines creating the path 
> in newmod.py files (under both cli and core directory) in your gnuradio python 
> installation
> It would be good if someone more familiar with the system could check if this 
> makes sense.
> If so, it would be nice to patch the library. I'm not sure if there is an 
> environment variable that would override the prefix as used by the library.

You can use the GR_PREFIX environment variable to override the prefix that it 
would use by default. So `export GR_PREFIX=/usr` would probably work for you. 
But again, that shouldn't be necessary.

> Apologies for the length of the email. As I said, the original problem was 
> resolved but maybe this can help someone installing 3.9 without building from 
> source.

I'm going to suggest that you file a bug on the GNU Radio GitHub so that the 
developers can track it. (The bug being that the returned prefix is not what it 
should be, pointing to a packaging or library problem. In this case, gr-modtool 
is just a casualty.) Hopefully that will get some more eyes on it and someone 
will be able to figure out what is happening.

Cheers,
Ryan