slimtoolkit/slim · error

bad architecture value

Error message

bad architecture value

What it means

The builder validates options.ImageConfig.Architecture against a strict allow-list: empty (defaults to amd64), amd64, or arm64. Any other value returns this error before image creation. The internal engine only supports building for these two architectures.

Solutions

1. Set ImageConfig.Architecture to "amd64" or "arm64" (or leave it empty to default to amd64)
2. Normalize inputs: map x86_64->amd64 and aarch64->arm64 before calling Build
3. Use lowercase values; "AMD64" is rejected
4. If another architecture is required, extend the switch in pkg/imagebuilder/internalbuilder/engine.go:65 and use a builder that supports the target (e.g. buildx)

Example fix

// before
opts.ImageConfig.Architecture = "x86_64"
// after
arch := "x86_64"
if arch == "x86_64" { arch = "amd64" }
if arch == "aarch64" { arch = "arm64" }
opts.ImageConfig.Architecture = arch // amd64|arm64|"" only

switch opts.ImageConfig.Architecture {
case "", "amd64", "arm64":
default:
    return fmt.Errorf("unsupported arch %q; use amd64 or arm64", opts.ImageConfig.Architecture)
}

if _, err := engine.Build(opts); err != nil {
    if strings.Contains(err.Error(), "bad architecture value") {
        opts.ImageConfig.Architecture = "amd64" // or map from runtime.GOARCH
    }
    return err
}

When it happens

Trigger: Setting SimpleBuildOptions.ImageConfig.Architecture to values like "386", "arm", "arm/v7", "s390x", or a typo such as "AMD64"/"x86_64" and calling Build.

Common situations: Porting a Dockerfile with FROM --platform=linux/386; copying architecture strings from `uname -m` output (x86_64, aarch64) instead of the Go architecture naming; multi-arch build scripts passing unsupported platforms.

Related errors

• empty image layer data source
• image layer data source path is not a tar file
• missing tags
• too many layers
• unknown image data source

AI-assisted analysis of slimtoolkit/slim@81940d17fa (2026-08-31). Data as JSON: /api/errors/aac4d6c5cf010875. Report an issue: GitHub.

Appendix: source

Thrown at pkg/imagebuilder/internalbuilder/engine.go:70

	if len(options.ImageConfig.Config.Entrypoint) == 0 &&
		len(options.ImageConfig.Config.Cmd) == 0 {
		return nil, fmt.Errorf("missing startup info")
	}

	if len(options.Layers) == 0 {
		return nil, fmt.Errorf("no layers")
	}

	if len(options.Layers) > 255 {
		return nil, fmt.Errorf("too many layers")
	}

	switch options.ImageConfig.Architecture {
	case "":
		options.ImageConfig.Architecture = "amd64"
	case "arm64", "amd64":
	default:
		return nil, fmt.Errorf("bad architecture value")
	}

	var img v1.Image
	if options.From == "" {
		//same as FROM scratch
		img = empty.Image
	} else {
		return nil, fmt.Errorf("custom base images are not supported yet")
	}

	imgRunConfig := v1.Config{
		User:            options.ImageConfig.Config.User,
		ExposedPorts:    options.ImageConfig.Config.ExposedPorts,
		Env:             options.ImageConfig.Config.Env,
		Entrypoint:      options.ImageConfig.Config.Entrypoint,
		Cmd:             options.ImageConfig.Config.Cmd,
		Volumes:         options.ImageConfig.Config.Volumes,
		WorkingDir:      options.ImageConfig.Config.WorkingDir,

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