Support updating policies in 'policy create' (#276)

This commit adds support for updating existing policies in
sourcetool policy create.

If an existing policy is found, sourcetool will ask if you
want to update it. If the policy data has not changed, then
nothing will be done.

Signed-off-by: Adolfo Garcia Veytia (puerco) <[email protected]>

Author: puerco

internal/cmd/policy.go

@@ -11,6 +11,7 @@ import (
 	"os"
 
 	"github.com/spf13/cobra"
+	"google.golang.org/protobuf/proto"
 	"sigs.k8s.io/release-utils/util"
 
 	"github.com/slsa-framework/slsa-source-poc/pkg/policy"
@@ -26,12 +27,14 @@ type policyCreateOpts struct {
 	branchOptions
 	interactive     bool
 	openPullRequest bool
+	update          bool
 }
 
 func (pco *policyCreateOpts) AddFlags(cmd *cobra.Command) {
 	pco.branchOptions.AddFlags(cmd)
 	cmd.PersistentFlags().BoolVar(&pco.openPullRequest, "pr", true, "Open a pull request to check-in the policy")
 	cmd.PersistentFlags().BoolVar(&pco.interactive, "interactive", true, "confirm before performing changes")
+	cmd.PersistentFlags().BoolVar(&pco.update, "update", false, "update if existing policy found")
 }
 
 func addPolicy(parentCmd *cobra.Command) {
@@ -172,6 +175,8 @@ just print the generated policy.
 				return err
 			}
 
+			fmt.Println()
+			fmt.Println(w(fmt.Sprintf("Creating source policy for %s#%s", opts.GetRepository().GetHttpURL(), opts.GetBranch().Name)))
 			// Create a new sourcetool object
 			srctool, err := sourcetool.New(
 				sourcetool.WithAuthenticator(authenticator),
@@ -187,8 +192,44 @@ just print the generated policy.
 			if err != nil {
 				return fmt.Errorf("checking for existing policy: %w", err)
 			}
+
+			if epcy != nil && !opts.interactive && !opts.update {
+				fmt.Fprintln(os.Stderr, "There is an existing policy in the community repository")
+				return nil
+			}
+
+			if epcy != nil && !opts.update {
+				fmt.Println()
+				fmt.Println("There is a policy already published for this repository.")
+				fmt.Println("Do you want to update it?")
+				fmt.Println()
+
+				_, s, err := util.Ask("Type 'yes' if you want to continue", "yes|no|no", 3)
+				if err != nil {
+					return err
+				}
+
+				if !s {
+					fmt.Println("Not changing existing policy.")
+					return nil
+				}
+			}
+
+			// If there is an existing policy, check if something changed.
+			var pcy *policy.RepoPolicy
+			pcy, err = srctool.CreateBranchPolicy(
+				context.Background(), opts.GetRepository(), []*models.Branch{opts.GetBranch()},
+			)
+			if err != nil {
+				return fmt.Errorf("creating new source policy: %w", err)
+			}
 			if epcy != nil {
-				return fmt.Errorf("repository already has a policy checked into the community repo")
+				if proto.Equal(pcy, epcy) {
+					fmt.Println()
+					fmt.Printf("Repository policy has not changed. All done.")
+					fmt.Println()
+					return nil
+				}
 			}
 
 			if opts.openPullRequest && opts.interactive {
@@ -222,7 +263,7 @@ open the pull request from there.
 
 			// Create the policy, this will open the pull request in the community
 			// repo if the options say so.
-			pcy, pr, err := srctool.CreateRepositoryPolicy(
+			_, pr, err := srctool.CreateRepositoryPolicy(
 				context.Background(), opts.GetRepository(), []*models.Branch{opts.GetBranch()},
 			)
 			if err != nil {