docker version JSON output uses mixed timestamp formats, seems to break downstream parsers (like VSCode DevContainers in remote configuration)

まず docker version --format '{{json .}}' を再現し、Client.BuildTime、Server.BuildTime、Server.Components[].Details.BuildTime フィールドを比較します。下流のパースへの影響を確認してから、docker version の構造化出力の実装を追跡します。関連する BuildTime の値が一貫した機械可読形式を使用し、その動作がテストでカバーされれば完了です。

Description

When running:

docker version --format '{{json .}}'

the Docker CLI emits inconsistent timestamp formats for BuildTime fields within the same JSON document.

Observed on Docker Engine / CLI 28.5.1 (Linux, arm64).

Example (abridged):
• Client.BuildTime: "Wed Oct 8 12:18:19 2025" (human-readable)
• Server.BuildTime: "2025-10-08T12:18:19.000000000+00:00" (RFC3339 / ISO-8601)
• Server.Components[].Details.BuildTime: "Wed Oct 8 12:18:19 2025" (human-readable)

This mixed formatting seems to break consumers that reasonably assume a consistent, machine-readable schema when using --format {{json .}}.

⸻

Assumed impact on downstream tooling (please reproduce!)

In a VS Code Dev Containers setup using Remote-SSH (local VS Code client, Docker running on a remote Linux host), the Dev Containers extension invokes docker version --format {{json .}} during initialization.

Because of the inconsistent BuildTime formats, the extension crashes during JSON parsing with:

TypeError: Cannot read properties of undefined (reading 'toString')

It seems to me that this error breaks the extension, as it prevents opening or reopening a workspace in a dev container on the remote host, effectively blocking a common remote development workflow.

Reproduce

Run:
docker version --format '{{json .}}'

Inspect the JSON output, specifically the BuildTime fields:
• Client.BuildTime
• Server.BuildTime
• Server.Components[].Details.BuildTime

Expected behavior

All BuildTime fields in structured JSON output should use a single, consistent, machine-readable format (preferably RFC3339 / ISO-8601), or the schema should otherwise guarantee consistency.

docker version

Client: Docker Engine - Community
 Version:           28.5.1
 API version:       1.51
 Go version:        go1.24.8
 Git commit:        e180ab8
 Built:             Wed Oct  8 12:18:19 2025
 OS/Arch:           linux/arm64
 Context:           default

Server: Docker Engine - Community
 Engine:
  Version:          28.5.1
  API version:      1.51 (minimum version 1.24)
  Go version:       go1.24.8
  Git commit:       f8215cc
  Built:            Wed Oct  8 12:18:19 2025
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          v1.7.28
  GitCommit:        b98a3aace656320842a23f4a392a33f46af97866
 runc:
  Version:          1.3.0
  GitCommit:        v1.3.0-0-g4ca628d1
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client: Docker Engine - Community
 Version:    28.5.1
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.29.1
    Path:     /usr/libexec/docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.40.0
    Path:     /usr/libexec/docker/cli-plugins/docker-compose

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0
 Server Version: 28.5.1
 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: systemd
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 CDI spec directories:
  /etc/cdi
  /var/run/cdi
 Discovered Devices:
  cdi: nvidia.com/gpu=0
  cdi: nvidia.com/gpu=GPU-52fdf34c-87be-b467-706b-48e19f89711c
  cdi: nvidia.com/gpu=all
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: b98a3aace656320842a23f4a392a33f46af97866
 runc version: v1.3.0-0-g4ca628d1
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.14.0-1015-nvidia
 Operating System: Ubuntu 24.04.3 LTS
 OSType: linux
 Architecture: aarch64
 CPUs: 20
 Total Memory: 119.7GiB
 Name: spark-bac8
 ID: 70a78378-a286-494d-b0d4-f15e68268112
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Experimental: false
 Insecure Registries:
  ::1/128
  127.0.0.0/8
 Live Restore Enabled: false

Additional Info

I am a part-time developer, not a deep expert. If there is another reason for the failing of the VSCode DevContainers extension feature, happy if you point me to the right direction...