This is one of two options for how we may embed ASMap files into Bitcoin Core releases. This approach here uses a binary dump of the file which is then committed to the source code as a header file. The alternative approach is not having the data in the source code but only adding it during the build phase of a release. I initially favored the second approach but it seems harder to achieve than I originally expected and I have also started to see the downsides of this approach as well. For example, we would not have the asmap data available in dev builds, meaning those who want to use asmap with dev builds would always need to provide a file as input. Also, opening a PR for new ASMap data before the first RC allows for earlier testing of the data and the PR itself is the natural place where reviewers can give feedback. If the asmap data is only included during the build phase potential problems can only be discovered while testing RC1 and a separate issue would need to be opened to coordinate a fix. I had also not realized that the binary dump header file approach here is very similar to the embedding of the seeds.
I am still planning to demo how the embedding would work during the build phase, but since I have started to like the approach shown here a lot more lately, I thought I would demo it and hear people’s opinions on it.
Currently, the binary dump header file could simply be generated using xxd -i path/to/ip_asn.map init/ip_asn.h. But I would also be open to adding an equivalent to makeseeds.py to make the process more convenient if people would prefer that.
