The current sign interface has the single Sign method:

Sign(claims jwt.Claims) (string, error)

When implementing an AWS KMS signer, the lack of the context means the remote operation doesn't participate in the main context, so it's unaware of request timeouts or server shutdown.

What about adding:

type SignerWithContext interface {
    Sign(ctx context.Context, claims jwt.Claims) (string, error)
}

An existing Signer implementation can be supported through a simple wrapper function:

type SignerWithContextFunc func Sign(claims jwt.Claims) (string, error)

func (s SignerWithContextFunc) (_ context.Context, claims jwt.Claims) (string, error) {
    return s(claims)
}

// ... 

signer := // Signer implementation
contextSigner := SignerWithContextFunc(signer.Sign)

Then a configuration item for WithContextSigner or similar. Thoughts?

I am able to raise a PR for this, or some more acceptable variation.