Why a separate module¶

This page explains why the sign and keys command builders live in their own module rather than inside go/signing or inside go-tool-base. The short answer is dependency-cycle avoidance; the longer answer is about keeping a light library light and letting more than one CLI share one command surface.

The three-way tension¶

Three facts pull against each other:

1. go/signing must stay tiny. Its whole promise is a framework-free signing/verification library whose module graph is just go-crypto and cockroachdb/errors. Pulling Cobra into it would tax every verify-only consumer with a CLI framework they never invoke.

2. More than one binary wants the same commands. go-tool-base exposes gtb sign / gtb keys; the standalone sigillum CLI wants byte-identical behaviour. Copy-pasting the command code into each host guarantees drift.

3. The commands must not drag in go-tool-base. If the builders lived in GTB's pkg/, then sigillum — and any other tool wanting just the signing commands — would have to import the entire framework. Worse, GTB itself already depends on go/signing, so co-locating the builders with the logic would knot the graph.

The resolution: a thin command-surface module¶

signing-cli sits in the middle:

        go/signing            (logic; tiny; no Cobra)
            ▲
            │  imported by
            │
        signing-cli           (Cobra command builders; this module)
            ▲            ▲
   imported │            │ imported by
        by  │            │
   go-tool-base      sigillum        (host binaries)

• It depends on go/signing (for the registry and OpenPGP helpers) and Cobra — nothing else heavy.
• It is imported by each host binary.
• It never imports go-tool-base.

Because the dependency arrows only ever point up — hosts → signing-cli → go/signing — there is no cycle. GTB can depend on signing-cli, and signing-cli never needs to depend back on GTB. The seam that makes the last point possible is the narrow Logger interface: the builders name a four-method logging contract instead of GTB's concrete logger type, so they never have to import GTB to log.

What each layer owns¶

That last row is why backends are the consumer's job — see Backends are the consumer's responsibility.

See also¶

• The Logger seam — the interface that lets these builders stay GTB-free.
• Backends are the consumer's responsibility — why this module imports no concrete backend.
• Attach the commands to a CLI — wire the builders onto your own root.