Hi all,
I’d like to start a discussion about running syft in a fully offline mode — meaning a configuration where syft is guaranteed not to make any outbound network call.
Why I need it
My organization places constraints on outbound traffic from the environments where syft runs. What I need in those cases is a guarantee that this invocation of syft does not talk to the network.
Where I currently see calls happening
As far as I can tell the network-touching paths are independent of each other and each has its own knob, or none:
- the application update check (SYFT_CHECK_FOR_APP_UPDATE)
- Can be disabled
- remote license/enrichment lookups for some ecosystems — see Enabling Syft network features from the CLI
- Deactivated by default
- image resolution itself: when a reference isn’t present locally, it gets pulled from the registry.
- This is the one I care most about and the one the thread above doesn’t cover
What I tried myself
I got reasonably far by constraining things from the outside: pinning the input to explicit local schemes so resolution can’t fall through to a registry, and turning the update check off via the env var. That covers the call sites I know about, but it only works because I know about them — the property lives in how I invoke syft rather than in syft’s own configuration, and I have to re-verify it on every upgrade.
When I looked at making it a real setting, the image-source side is where I got stuck: the pull happens in stereoscope, so there’s no obvious single point in syft where I could enforce “no remote sources” for the whole run without either touching stereoscope as well or scattering checks around. I didn’t see an easy way that felt like it matched the existing design.
Open questions
Mostly I’d like to hear what shape you’d consider acceptable, rather than propose something and have it be wrong:
- Is this actually a feature / configuration option that you could see in the product?
- Is a single top-level switch the right model at all — something like --offline / SYFT_OFFLINE=true that makes any operation requiring the network a hard error instead of a fallback? If so, how should it interact with --enrich and the more granular settings; does offline always win regardless of precedence?
- Or does this belong lower down, as a “no remote sources” option in stereoscope that syft just surfaces? That seems closer to where the behaviour actually lives, but it’s a larger surface.
- Is “fail loudly” the behaviour you’d want, or would you expect offline to degrade gracefully (skip enrichment, emit a warning) and only hard-fail when the image itself can’t be resolved?
Contributing
I’m happy to contribute hre rather than just file a request.
Two things held me back from opening a PR directly: it looks like it touches both syft and stereoscope, and I wasn’t sure what you’d expect in terms of style and structure across the two repos — and more importantly I didn’t want to build something in a direction that wouldn’t be accepted.
Thanks!