Docker Images

Sign Docker images with cosign

Sign your Docker images after they're pushed.

Config

docker_signs:
  - artifacts: all
    cmd: cosign
    args: ["sign", "--key=cosign.key", "{{ Artifact }}@{{ Digest }}"]

Docker sign config fields

Field	Type	Default	Description
`id`	string		Unique identifier for this docker sign config (referenced by `ids` filters elsewhere).
`artifacts`	string	`""`	Which Docker artifacts to sign: `all`, `images`, `manifests`, `none`, or `""` (empty — the default — signs the canonical Docker images). The singular `image` / `manifest` are not accepted and hard-error at release time.
`cmd`	string	`cosign`	Signing command to invoke.
`args`	list	`["sign", "--key=cosign.key", "{{ .Artifact }}@{{ .Digest }}", "--yes"]`	Arguments passed to the signing command. `{{ Artifact }}` is replaced by the digest-pinned image reference and `{{ Signature }}` by the synthesized `<image>@<digest>.sig` name before the rest is rendered as a template; `{{ Digest }}` renders the image digest. The `${artifact}` shell variables the binary/archive path expands are not expanded here and reach the signing command as literal text.
`signature`	string	—	Ignored. A container signature is stored in the registry beside the image rather than written to a file, so anodizer synthesizes the `<image>@<digest>.sig` name its argv substitutes and reads this template nowhere. `anodizer check config` warns when it is set.
`certificate`	string		Certificate file whose presence selects cosign's bundle verification mode. The path itself never reaches the signing command — `{{ Certificate }}` in `args:` renders empty.
`ids`	list	all	Only sign images from docker configs whose `id` is in this list.
`stdin`	string		Content written to the signing command's stdin (e.g. a passphrase); rendered as a template (e.g. `{{ Env.GPG_PASSPHRASE }}`) with nothing substituted first, so neither `{{ Artifact }}` nor `${artifact}` names anything here.
`stdin_file`	string		Path to a file whose content is written to the signing command's stdin.
`env`	list		Environment variables passed to the signing command (`KEY=VALUE` strings).
`output`	bool	`false`	Capture and log the signing command's stdout/stderr.
`if`	string		Template-conditional: skip this config when the rendered result is `false` or empty. An absent, empty or blank `if:` imposes no gate and always runs; the falsy test applies to what a non-blank gate renders.

Images are signed one at a time. A keyless config (no --key argument) also takes the same host-level advisory lock as keyless binary/archive signing, so two anodizer processes on one host queue on the sigstore TUF trust store instead of colliding on it.