buildx build produces git not found warning even with attestations disabled

[illusori]

Contributing guidelines

• I've read the contributing guidelines and wholeheartedly agree

I've found a bug and checked that ...

• ... the documentation does not mention anything about my problem
• ... there are no open or closed issues that are related to my problem

Description

The WARNING: buildx: git was not found in the system. Current commit information was not captured by the build warning appears on systems without git installed even if attestations are disabled with --provenance=false and --sbom=false.

I'm presuming attestations are the cause, but there's no documentation for this warning and the documentation on just how attestations data is gathered is fairly threadbare. The fact that this warning gives no indication of why it's a problem and why buildx is complaining about not finding git and what to do to remedy the situation if git not being available is correct behaviour suggests that either the warning and/or documentation is inadequate.

Expected behaviour

If attestations are switched off, buildx shouldn't be trying to gather data for them.

Actual behaviour

Warning generated suggests that attestations data is being gathered regardless of whether it's enabled or not.

Buildx version

github.com/docker/buildx v0.10.4 c513d34

Docker info

Client:
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.10.4
    Path:     /usr/libexec/docker/cli-plugins/docker-buildx

Server:
 Containers: 3
  Running: 2
  Paused: 0
  Stopped: 1
 Images: 42
 Server Version: 24.0.2
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 3dce8eb055cbb6872793272b4f20ed16117344f8
 runc version: v1.1.7-0-g860f061
 init version: de40ad0
 Security Options:
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 5.15.49-linuxkit-pr
 Operating System: Docker Desktop
 OSType: linux
 Architecture: x86_64
 CPUs: 4
 Total Memory: 3.841GiB
 Name: docker-desktop
 ID: a7556ca5-8fa3-4032-8a01-d9b50ca2c610
 Docker Root Dir: /var/lib/docker
 Debug Mode: true
  File Descriptors: 70
  Goroutines: 102
  System Time: 2023-06-14T18:19:57.576077242Z
  EventsListeners: 11
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Registry: https://index.docker.io/v1/
 Experimental: true
 Insecure Registries:
  hubproxy.docker.internal:5555
  127.0.0.0/8
 Live Restore Enabled: false

Builders list

default * docker                                                        
  default default         running v0.11.7-0.20230525183624-798ad6b0ce9f linux/amd64, linux/amd64/v2, linux/amd64/v3, linux/arm64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/mips64le, linux/mips64, linux/arm/v7, linux/arm/v6

Configuration

Not applicable.

Build logs

No response

Additional info

Reproduced with a git source tree copied over to a minimal build system without git installed, then docker build ran.

[crazy-max]

I'm not able to repro with latest release:

$ docker run -d --privileged --name test-1881 docker:24-dind
$ docker exec -it test-1881 sh
/ # docker info
Client:
 Version:    24.0.4
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.11.1
    Path:     /usr/local/libexec/docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.20.0
    Path:     /usr/local/libexec/docker/cli-plugins/docker-compose

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 1
 Server Version: 24.0.4
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 1
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 1677a17964311325ed1c31e2c0a3589ce6d5c30d
 runc version: v1.1.7-0-g860f061
 init version: de40ad0
 Security Options:
  seccomp
   Profile: builtin
 Kernel Version: 5.15.90.1-microsoft-standard-WSL2
 Operating System: Alpine Linux v3.18 (containerized)
 OSType: linux
 Architecture: x86_64
 CPUs: 32
 Total Memory: 31.31GiB
 Name: f8814648eedc
 ID: 8d767066-e401-4a82-8254-07d3b4d7e294
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false
 Product License: Community Engine

WARNING: No blkio throttle.read_bps_device support
WARNING: No blkio throttle.write_bps_device support
WARNING: No blkio throttle.read_iops_device support
WARNING: No blkio throttle.write_iops_device support
/ # docker buildx ls
NAME/NODE DRIVER/ENDPOINT STATUS  BUILDKIT                              PLATFORMS
default * docker
  default default         running v0.11.7-0.20230525183624-798ad6b0ce9f linux/amd64, linux/amd64/v2, linux/amd64/v3, linux/arm64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/mips64le, linux/mips64, linux/arm/v7, linux/arm/v6
/ # type git
git: not found
/ # cd /tmp
/tmp # docker buildx build -t casspy -f- . <<EOF
> FROM busybox
> RUN echo hello
> EOF
[+] Building 2.8s (6/6) FINISHED                                                                                                                                                                                  docker:default
 => [internal] load .dockerignore                                                                                                                                                                                           0.1s
 => => transferring context: 2B                                                                                                                                                                                             0.0s 
 => [internal] load build definition from Dockerfile                                                                                                                                                                        0.1s 
 => => transferring dockerfile: 65B                                                                                                                                                                                         0.0s 
 => [internal] load metadata for docker.io/library/busybox:latest                                                                                                                                                           1.7s
 => [1/2] FROM docker.io/library/busybox@sha256:2376a0c12759aa1214ba83e771ff252c7b1663216b192fbe5e0fb364e952f85c                                                                                                            0.5s
 => => resolve docker.io/library/busybox@sha256:2376a0c12759aa1214ba83e771ff252c7b1663216b192fbe5e0fb364e952f85c                                                                                                            0.0s 
 => => sha256:2376a0c12759aa1214ba83e771ff252c7b1663216b192fbe5e0fb364e952f85c 2.29kB / 2.29kB                                                                                                                              0.0s
 => => sha256:67a8ef886e2ca4055f00e7cd13aedb9b24148c1451a6832d16fcc997a157eedc 528B / 528B                                                                                                                                  0.0s 
 => => sha256:5242710cbd55829f6c44b34ff249913bb7cee748889e7e6925285a29f126aa78 1.46kB / 1.46kB                                                                                                                              0.0s 
 => => sha256:809d8e20e2032a1e633651f87c525fd60e5d5b1bc41560aa63920962700c44fd 2.22MB / 2.22MB                                                                                                                              0.3s 
 => => extracting sha256:809d8e20e2032a1e633651f87c525fd60e5d5b1bc41560aa63920962700c44fd                                                                                                                                   0.1s
 => [2/2] RUN echo hello                                                                                                                                                                                                    0.3s
 => exporting to image                                                                                                                                                                                                      0.1s
 => => exporting layers                                                                                                                                                                                                     0.1s
 => => writing image sha256:fc2ff000354a2c353020f66f883a4c089af373ed0a5ca16bc6c5a8ecb73240e1                                                                                                                                0.0s 
 => => naming to docker.io/library/casspy                                                                                                                                                                                   0.0s 
/tmp #

[ohthepain]

I am getting the same error message on macOS even though I have git installed.

level=warning msg="buildx: git was not found in the system. Current commit information was not captured by the build"

[RobertBeilich]

@crazy-max , you are not able to reproduce, because you forgot the important part: executing it in a git repo (or something that looks like one)

adjusting your minimal example above, just before you run docker buildx [...] run mkdir .git. You don't even need to have an actual repository, just having the folder present produces the warning.

[jedevc]

Okay, so I can confirm this is maybe an issue.

Reproduction:

• Start on a host without git
• Build an image with --provenance=false, with a git repository in the context
• The warning buildx: git was not found in the system. Current commit information was not captured by the build is still produced.

Note

For any users coming across this, you can disable the warning by setting BUILDX_GIT_INFO=false in the environment.

The logic here is at fault:

buildx/build/build.go

Lines 736 to 757 in f35b2b7

	multiDriver := len(m[k]) > 1
	hasMobyDriver := false
	gitattrs, err := getGitAttributes(ctx, opt.Inputs.ContextPath, opt.Inputs.DockerfilePath)
	if err != nil {
	logrus.WithError(err).Warn("current commit information was not captured by the build")
	}
	for i, np := range m[k] {
	node := nodes[np.driverIndex]
	if node.Driver.IsMobyDriver() {
	hasMobyDriver = true
	}
	opt.Platforms = np.platforms
	so, release, err := toSolveOpt(ctx, node, multiDriver, opt, np.bopts, configDir, w, docker)
	if err != nil {
	return nil, err
	}
	for k, v := range gitattrs {
	so.FrontendAttrs[k] = v
	}
	defers = append(defers, release)
	m[k][i].so = so
	}

While there is still value in attaching the vcs info if provenance is disabled (we still generated provenance to store in the history api even if it's disabled from the output), it is still quite a confusing warning to display unconditionally if provenance is disabled.

We could sort the call to getGitAttributes to be after the toSolveOpt call where we determine whether to enable provenance. Then we could only display the warning in cases where provenance is enabled? Perhaps we should take a leaf out of golang's toolchain and just silently fail?

(if we ever completed the work in moby/buildkit#1048, then we could potentially avoid this issue entirely 🎉)

[illusori]

@jedevc Thanks for tracking this down, my use case turned to to be too complicated and entangled for me to easily extract simple steps to reproduce, but it looks like you've found the issue. I can confirm that BUILDX_GIT_INFO=false in the environment suppresses it, so it looks like you've found the right problem. :)

[jimfilippou]

For anyone experiencing the following issue

Please check your .dockerignore file and see if you have backslashes instead of forward slashes, I mistakenly added backslashes through GitHub Copilot thinking it doesn't matter and turns out this was the issue.