skaffold build fails with "failed to parse platform" when building loadgenerator

[chris4474]

Describe the bug

Generating tags...

• loadgenerator -> registry.symphorines.home/microservice/loadgenerator:sic-jss-277-g5f5b66c8
  Checking cache...
• loadgenerator: Not found. Building
  Starting build...
  Building [loadgenerator]...
  Sending build context to Docker daemon 8.192kB
  Step 1/12 : FROM --platform=$BUILDPLATFORM python:3.12.8-alpine@sha256:54bec49592c8455de8d5983d984efff76b6417a6af9b5dcc8d0237bf6ad3bd20 AS base
  docker build failure: failed to parse platform : "" is an invalid OS component of "": OSAndVersion specifier component must match "^([A-Za-z0-9_-]+)(?:\(([A-Za-z0-9_.-]*)\))?$": invalid argument. Please fix the Dockerfile and try again..

To Reproduce

$ git clone https://github.com/GoogleCloudPlatform/microservices-demo.git
$ cd microservices-demo/
$ skaffold build -b loadgenerator

Logs

(see attachement)

log.log

Screenshots

n/a

Environment

$ skaffold version
v2.14.1

$ skaffold config list -a
skaffold config:
global:
default-repo: registry.symphorines.home/microservice
survey:
last-prompted: "2025-03-03T22:01:45Z"
collect-metrics: true
update:
last-prompted: "2025-03-04T09:27:09+01:00"
kubeContexts: []

$ cat /etc/os-release
PRETTY_NAME="Ubuntu 24.04.2 LTS"
NAME="Ubuntu"
VERSION_ID="24.04"
VERSION="24.04.2 LTS (Noble Numbat)"
VERSION_CODENAME=noble
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=noble
LOGO=ubuntu-logo

$ docker version
Client: Docker Engine - Community
Version: 28.0.1
API version: 1.48
Go version: go1.23.6
Git commit: 068a01e
Built: Wed Feb 26 10:41:12 2025
OS/Arch: linux/amd64
Context: default

Server: Docker Engine - Community
Engine:
Version: 28.0.1
API version: 1.48 (minimum version 1.24)
Go version: go1.23.6
Git commit: bbd0a17
Built: Wed Feb 26 10:41:12 2025
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: 1.7.25
GitCommit: bcc810d6b9066471b0b6fa75f557a15a1cbf31bb
runc:
Version: 1.2.4
GitCommit: v1.2.4-0-g6c52b3f
docker-init:
Version: 0.19.0
GitCommit: de40ad0

$ kubectl config view --minify
apiVersion: v1
clusters:

• cluster:
  certificate-authority-data: DATA+OMITTED
  server: https://192.168.1.115:6443
  name: rpi
  contexts:
• context:
  cluster: rpi
  namespace: microservice
  user: rpi
  name: rpi
  current-context: rpi
  kind: Config
  preferences: {}
  users:
• name: rpi
  user:
  client-certificate-data: DATA+OMITTED
  client-key-data: DATA+OMITTED

$ kubectl version
Client Version: v1.32.1
Kustomize Version: v5.5.0
Server Version: v1.31.6+k3s1

Additional context

I can build the other components individually using -b flag

Exposure

It happens all the time (each time I try to build loadgenerator)