The image source provider now reads images with `image.WithLazyLayerSquashes`: the image squash is built during the read, and each lower layer's squash only when something reads it. A squashed scan never does, so it skips a full file tree copy per layer.
- squashed scans: faster, much less memory on images with many layers
- `scan`/`attest` with all-layers or deep-squashed stay eager (an internal ctx flag), since eager squashing overlaps with fetching and indexing and is faster when every layer gets read
- library callers going through `syft.GetSource` get lazy for every scope, since the scope isn't known when the image is read. All-layers is still correct, just slower
- no public API change
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
stereoscope is replacing `image.WithImageSquashOnly` with lazy layer squashes, where every layer keeps a usable squash. That removes the need for `GetSourceConfig.WithImageSquashOnly` and the scope guard in `FileResolver`, so both go.
- bumps stereoscope to `feat/lazy-layer-squashes` (anchore/stereoscope `43c8f7e`), pending that PR merging
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
- stereoscope builds a squashed tree for every layer, each a full copy of the one below, so memory
grows with layers x files. The squashed scope only ever reads the top one.
- new `GetSourceConfig.WithImageSquashOnly(bool)` (and `sourceproviders.Config` field) reads images
with stereoscope's `image.WithImageSquashOnly`, scoped to that one read
- the CLI turns it on when `--scope squashed` (the default)
- an image source read this way returns an error from `FileResolver` for `all-layers` and
`deep-squashed` instead of panicking on the missing layer squashes
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
Alex Goodman