Refactor verification output. (sigstore#632)

This will make it easier to customize for attestation output.

Signed-off-by: Dan Lorenc <lorenc.d@gmail.com>

cmd/cosign/cli/verify.go

@@ -180,14 +180,14 @@ func (c *VerifyCommand) Exec(ctx context.Context, args []string) (err error) {
 			return err
 		}
 
-		PrintVerification(imageRef, verified, co, c.Output)
+		PrintVerificationHeader(imageRef, co)
+		PrintVerification(imageRef, verified, c.Output)
 	}
 
 	return nil
 }
 
-// PrintVerification logs details about the verification to stdout
-func PrintVerification(imgRef string, verified []cosign.SignedPayload, co *cosign.CheckOpts, output string) {
+func PrintVerificationHeader(imgRef string, co *cosign.CheckOpts) {
 	fmt.Fprintf(os.Stderr, "\nVerification for %s --\n", imgRef)
 	fmt.Fprintln(os.Stderr, "The following checks were performed on each of these signatures:")
 	if co.ClaimVerifier != nil {
@@ -206,6 +206,10 @@ func PrintVerification(imgRef string, verified []cosign.SignedPayload, co *cosig
 		fmt.Fprintln(os.Stderr, "  - The signatures were verified against the specified public key")
 	}
 	fmt.Fprintln(os.Stderr, "  - Any certificates were verified against the Fulcio roots.")
+}
+
+// PrintVerification logs details about the verification to stdout
+func PrintVerification(imgRef string, verified []cosign.SignedPayload, output string) {
 
 	switch output {
 	case "text":

cmd/cosign/cli/verify_attestation.go

@@ -170,8 +170,9 @@ func (c *VerifyAttestationCommand) Exec(ctx context.Context, args []string) (err
 			return err
 		}
 
+		PrintVerificationHeader(imageRef, co)
 		// The attestations are always JSON, so use the raw "text" mode for outputting them instead of conversion
-		PrintVerification(imageRef, verified, co, "text")
+		PrintVerification(imageRef, verified, "text")
 	}
 
 	return nil

cmd/sget/cli/sget.go

@@ -68,7 +68,8 @@ func SgetCmd(ctx context.Context, imageRef, keyRef string) (io.ReadCloser, error
 		if err != nil {
 			return nil, err
 		}
-		cli.PrintVerification(imageRef, sp, co, "text")
+		cli.PrintVerificationHeader(imageRef, co)
+		cli.PrintVerification(imageRef, sp, "text")
 	}
 
 	img, err := remote.Image(ref, co.RegistryClientOpts...)