cmd/go: stamp git/vcs current HEAD hash/commit hash/dirty bit in binaries #37475
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This may be a duplicate of #29814. |
Maybe we'll auto-bump this with a bot over time. See golang/go#37475 & golang/go#29814 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
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We should figure out exactly what we want to record. It would be helpful to time how much overhead this would be in 'go build'. @bcmills, do you have any numbers about how much time this would add? |
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BTW I agree it's a duplicate of #29814 but I'll keep using this one because it is marked as a proposal and already appeared in the minutes. |
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Hmm, I realized that I didn't account for checking tags in the above calculations. Still, I expect those costs will be order-of-magnitude similar to any other |
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I'd like to point out a (maybe small) problem with this approach: changing the version of source code, but not the code itself will cause the binary to change. Let me explain the use-case I have that will be broken by this change:
If the Helm chart contents and the binaries don't change, then no upgrades are performed by Kubernetes. If the version of the checkout is stamped into every Go binary, then this scheme crumbles and:
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@dottedmag, what if we made it conditional on importing a new package, say Would that work for your use case? |
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I'm in a practically identical case to @dottedmag. Inevitably, somewhere in the monorepo we will (perhaps unintentionally) bring in a dependency that depends on a magic package that breaks deterministic builds. I think for most common cases, having this proposal enabled by default would be preferable. For my use case, I would be satisfied if there was a documented way to opt out of it. We already are using |
I agree with @mark-rushakoff: relying on imports will be brittle unless this import is considered only for It's not an author of some recursively included library, but a builder of a final binary who in a position to decide whether to put versioning information into the binary or not. |
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@dottedmag, note that many functionally-equivalent builds will already produce slightly different binaries due to the version-stamping for This proposal would case more of the same sort of version churn, but it is fundamentally the same churn. That suggests that we may want to provide an option to disable version stamping in general. IMO, that should be a separate proposal. |
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True. In practice, it is not a problem as changing the versions of dependencies nearly always changes the code of dependencies — nobody is updating versions of dependencies endlessly for no reason, usually, they only get updated to get a new feature or a bugfix. Filed #37693. |
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The discussion above about reproducible builds sounds like it would be satisfied by having the version embedded by default but also having an opt-out command-line flag; no special package needed. Do I have that right, @dottedmag and @mark-rushakoff? |
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Yes, I think a flag to opt out of embedding version details would suffice for reproducible builds. It would be nice if there was a single flag like I don't care about reproducible builds when I'm at the command line building something for my own use; I care about reproducible builds when I am writing build scripts that run as part of a CI/CD pipeline, so it is not a big deal if I need to look up the whole collection of settings to make those builds reproducible. |
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@rsc Correct. |
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OK, it sounds like everyone agrees about doing this by default, with a flag to turn it off. That buildid step could install the git version info too. I'm confident git will be faster than the link. Based on the discussion, then, this seems like a likely accept, although we may not be able to implement it until the next release (Go 1.16). |
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Will this include just the commit hash or also a (any?) version tag |
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Version tags introduce many sharp edges, at least for git… since you can have a git repo cloned without having fetched all tags, or can have different local tags, or can add a tag to a SHA at any point in time, using the nearest tag (e.g. |
Temporary fix until golang#37475 is done. (cherry picked from commit ba89304) Change-Id: I204f03bc62c6f2295a8bc66d3f0bb2132153bc27
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Change https://go.dev/cl/391803 mentions this issue: |
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Change https://go.dev/cl/391809 mentions this issue: |
… "go" from $PATH Updates #37475. Change-Id: I8c3237438da3e9521ce3be26a0b5d5ca36944b17 Reviewed-on: https://go-review.googlesource.com/c/go/+/391803 Trust: Bryan Mills <bcmills@google.com> Run-TryBot: Bryan Mills <bcmills@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Daniel Martí <mvdan@mvdan.cc> Trust: Daniel Martí <mvdan@mvdan.cc>
Also update cmd/dist to avoid setting gcflags and ldflags explicitly when the set of flags to be set is empty (a verbose way of specifying the default behavior). Stamping was disabled for the Go standard library in CL 356014 due to the cmd/dist flags causing cmd/go to (correctly) report the resulting binaries as stale. With cmd/dist fixed, we can also remove the special case in cmd/go, which will allow tests of binaries in 'cmd' to read the build info embedded in the test binary. That build info may be useful to determine (say) whether runtime.GOROOT ought to work without GOROOT set in the environment. For #51483 Updates #37475 Change-Id: I64d04f5990190094eb6c0522db829d3bdfa50ef3 Reviewed-on: https://go-review.googlesource.com/c/go/+/391809 Trust: Bryan Mills <bcmills@google.com> Run-TryBot: Bryan Mills <bcmills@google.com> Reviewed-by: Russ Cox <rsc@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org>
This allows building runc without passing the VERSION build-arg, but requires
go 1.16 or up.
Unfortunately, there's no easy way to get the git-commit from the filesystem
(possibly through `.git/logs/HEAD`, which is a large file); a proposal has been
accepted to add git information ([1]), which will be included in go1.18.
For users building through `go install github.com/opencontainers/runc@version`),
we may be able to use runtime/debug.BuildInfo() ([2]). BuildInfo provides the
module version and checksum, but only when building using `go install`. When
building from a local module (git clone), the version is alway set to `(devel)`,
see [3].
We could consider add module (optional) if available, e.g.:
// Print module information if available. When built from local source,
// (using git clone), module version is not available, and version is
// set to "(devel)"; see golang/go#29814, and golang/go#37475.
if bi, ok := debug.ReadBuildInfo(); ok && bi.Main.Version != "(devel)" {
v = append(v, "module version: "+bi.Main.Version+", sum: "+bi.Main.Sum)
}
With this patch (on go1.16):
make
go build -trimpath "-buildmode=pie" -tags "seccomp" -ldflags "-X main.gitCommit=v1.0.0-133-g27d75cca " -o runc .
./runc --version
runc version 1.0.0+dev
commit: v1.0.0-133-g27d75cca
spec: 1.0.2-dev
go: go1.16.7
libseccomp: 2.3.3
[1]: golang/go#37475
[2]: https://pkg.go.dev/runtime/debug#BuildInfo
[3]: golang/go#29814
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
@bcmills I would read this as "both commit hash and tag" will be implemented, or rather are since the PR is merged. Looking at the buildinfo from 1.18, only the commit hash is present. Is there further discussion or efforts for adding the (most recent) tag? |
(Related but different than #35667)
cmd/go currently embeds all the module dep information in binaries and it's readable with e.g. https://godoc.org/rsc.io/goversion/version but it does not include any information about the top-level module's version.
I propose that cmd/go look at {git,svn,etc} state and include in the binary:
Currently many projects do this by hand with a
build-program.shand stamping it manually with--ldflags=-X foo=bar, but that means programs built the normal Go way lack that information, and people end up with non-portable (shell, often) build scripts.I've hit this enough times with my own projects that it's actively frustrating me. It's worse when programs are clients that want to report their version number to a server (which might want to do analytics, build horizon enforcement, protocol version negotiation, etc) and then can't. There are alternative ways to do all that, but they're tedious.
Mostly I'm concerned that people have bespoke, often non-portable build scripts.
Note, July 15, 2021: This proposal was accepted but has not yet been implemented. Per discussion in #37693, when it does get implemented, we need to include a flag to turn this behavior off. - rsc
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