Does --mount=type=cache actually support the src/source parameter in buildah run?

[polettix]

The docs for buildah run have the following in the --mount section:

Common Options:
- src, source: mount source spec for bind and cache. [...]

This made me think that it's possible to set a specific path in the host as the src when using type=cache, much like what happens for type=bind, but apparently the src=... part is ignored with type=cache(*).

I think that the documentation should be changed to move src/source from Common Options into Options specific to bind, as well as adding documentation for the rw option, but I'd like a reality check before proposing a PR based on a misunderstanding.

(*) I know that I can set read/write mode with type=bind,rw,... (although undocumented) so no big deal from a functional point of view.

[nalind]

This was broken, but should have been fixed while fixing some time-of-check-time-of-use problems that the "src" option opened us up to. Which version are you using? It should work as expected at least as of v1.39, v1.38.1, v1.37.6, v1.35.5, v1.33.12, v1.29.5, v1.27.6, and v1.26.9.

[polettix]

Sorry, I did not include this bit of information:

$ buildah version
Version:         1.28.2
Go Version:      go1.19.8
Image Spec:      1.1.0-rc2
Runtime Spec:    1.0.2-dev
CNI Spec:        1.0.0
libcni Version:
image Version:   5.23.1
Git Commit:
Built:           Thu Jan  1 01:00:00 1970
OS/Arch:         linux/amd64
BuildPlatform:   linux/amd64

It's the stock one coming with Debian 12:

PRETTY_NAME="Debian GNU/Linux 12 (bookworm)"
NAME="Debian GNU/Linux"
VERSION_ID="12"
VERSION="12 (bookworm)"
VERSION_CODENAME=bookworm
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"

Not sure what "as of" means in your answer - I see v1.26.9, so should I expect that v1.28.2 is included being greater than that?

Additionally, is the rw option lacking from the documentation or has it been removed after v1.28.2?

[nalind]

That security fix, and this bug fix that was included with it, was not backported to the 1.28 branch. The versions I listed were the versions cut from branches that we did the backport to, except for 1.39, where the branch was made after the change was merged into the main development branch.

The "rw" option is accepted, though as it's the default for cache mounts, I don't expect it to be explicitly requested very often, and I agree that it should be added to the man page.