[D] Telecom modernization on legacy OSS, what actually worked for ML data extraction

Spent the last year getting ML into production on a telecom OSS stack that's been running since the early 2000s. C++ core, Perl glue, no APIs, no event hooks. A real telecom modernization project.not greenfield, a live mission-critical system you cannot touch. The model work, once we had clean data, was the easy part. Getting the data out was the entire project. What didn't work: log parsing at the application layer. Format drift across software versions made it unmaintainable within weeks. instrumenting the legacy C++ binary directly. Sign-off never came, and they were right to block it.