$ the-wire · showcase
JAX BACKWARD PASS NOW LOGS DEBUG DATA. CLOUD AUTH TIGHTENS mTLS PRECEDENCE
By RepoJournal · Filed · About Google · Composed from the cited sources · methodology
2 people shipped this
JAX's autodiff pipeline shipped structured logging from transpose rules, letting you inspect what's happening inside the backward pass without tanking performance.
The backward pass logging feature [1] is the headline: transpose rules can now return named pytrees of data that flow out through `f_vjp.with_logs(out_ct)`, returning both arg cotangents and a logs dict. Plain `f_vjp(out_ct)` still works and drops the logs entirely, so JIT compiles them away. Existing rules need zero changes; they just keep returning None from the new output slot. This composes with gradient refs for even finer instrumentation. Alongside that, the vjp3 infrastructure caught up to recent AD features [2], with xla_call_metadata_call and compute_on rules now tracking lojax rules, structured residuals, and backward pass logging. The docs also got a refresh [3] on custom derivatives with clearer rules sections and new examples. On the auth front, google-cloud-python consolidated its mTLS cert discovery logic [4] into a unified helper, killing scattered checks across multiple functions. More importantly, X.509 Workload Identity Federation now takes hard precedence over SecureConnect by checking the consolidated path first, tightening the precedence order.
Action items
- → Pin JAX at your current version if backward pass logging is off-limits; opt in by calling .with_logs when you need it google/jax [plan]
- → Update google-cloud-python auth if you rely on WIF cert precedence; the old SecureConnect fallback is now subordinate googleapis/google-cloud-python [plan]
- → Review JAX custom derivative docs if you write transpose rules; the reorganized guide is now live google/jax [monitor]
References
- [1] [vjp3] add a way to log data out of the backward pass ↗ google/jax
- [2] [vjp3] xla_call_metadata_call / compute_on lojax rules, sres, logging ↗ google/jax
- [3] [docs] improve 301 page on custom derivatives with hijax ↗ google/jax
- [4] fix(auth): centralize cert discovery logic and steps ↗ googleapis/google-cloud-python
