Do not pass around signing key when unnecessary

The working checkout already holds the configuration for git, which
includes the key that should be used when doing signing operations with
git.

Default to the one in the configuration but leave the option open to
pass along a different key for specific operations.

daemon/daemon.go

@@ -13,10 +13,10 @@ import (
 
 	"github.com/weaveworks/flux"
 	"github.com/weaveworks/flux/api"
-	"github.com/weaveworks/flux/api/v10"
-	"github.com/weaveworks/flux/api/v11"
-	"github.com/weaveworks/flux/api/v6"
-	"github.com/weaveworks/flux/api/v9"
+	v10 "github.com/weaveworks/flux/api/v10"
+	v11 "github.com/weaveworks/flux/api/v11"
+	v6 "github.com/weaveworks/flux/api/v6"
+	v9 "github.com/weaveworks/flux/api/v9"
 	"github.com/weaveworks/flux/cluster"
 	"github.com/weaveworks/flux/event"
 	"github.com/weaveworks/flux/git"
@@ -419,9 +419,8 @@ func (d *Daemon) updatePolicy(spec update.Spec, updates policy.Updates) updateFu
 			commitAuthor = spec.Cause.User
 		}
 		commitAction := git.CommitAction{
-			Author:     commitAuthor,
-			Message:    policyCommitMessage(updates, spec.Cause),
-			SigningKey: d.GitConfig.SigningKey,
+			Author:  commitAuthor,
+			Message: policyCommitMessage(updates, spec.Cause),
 		}
 		if err := working.CommitAndPush(ctx, commitAction, &note{JobID: jobID, Spec: spec}); err != nil {
 			// On the chance pushing failed because it was not
@@ -465,9 +464,8 @@ func (d *Daemon) release(spec update.Spec, c release.Changes) updateFunc {
 				commitAuthor = spec.Cause.User
 			}
 			commitAction := git.CommitAction{
-				Author: commitAuthor,
+				Author:  commitAuthor,
 				Message: commitMsg,
-				SigningKey: d.GitConfig.SigningKey,
 			}
 			if err := working.CommitAndPush(ctx, commitAction, &note{JobID: jobID, Spec: spec, Result: result}); err != nil {
 				// On the chance pushing failed because it was not

git/gittest/repo_test.go

@@ -72,6 +72,7 @@ func TestSignedCommit(t *testing.T) {
 	defer gpgCleanup()
 
 	config := TestConfig
+	config.SigningKey = signingKey
 	config.GPGHomeDir = gpgHome
 	checkout, repo, cleanup := CheckoutWithConfig(t, config)
 	defer cleanup()
@@ -88,7 +89,7 @@ func TestSignedCommit(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
-	commitAction := git.CommitAction{Message: "Changed file", SigningKey: signingKey}
+	commitAction := git.CommitAction{Message: "Changed file"}
 	if err := checkout.CommitAndPush(ctx, commitAction, nil); err != nil {
 		t.Fatal(err)
 	}
@@ -123,14 +124,15 @@ func TestSignedTag(t *testing.T) {
 	defer gpgCleanup()
 
 	config := TestConfig
+	config.SigningKey = signingKey
 	config.GPGHomeDir = gpgHome
 	checkout, _, cleanup := CheckoutWithConfig(t, config)
 	defer cleanup()
 
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
-	tagAction := git.TagAction{Revision: "HEAD", Message: "Sync pointer", SigningKey: signingKey}
+	tagAction := git.TagAction{Revision: "HEAD", Message: "Sync pointer"}
 	if err := checkout.MoveSyncTagAndPush(ctx, tagAction); err != nil {
 		t.Fatal(err)
 	}

git/working.go

@@ -133,6 +133,9 @@ func (c *Checkout) CommitAndPush(ctx context.Context, commitAction CommitAction,
 	}
 
 	commitAction.Message += c.config.SkipMessage
+	if commitAction.SigningKey == "" {
+		commitAction.SigningKey = c.config.SigningKey
+	}
 
 	if err := commit(ctx, c.dir, c.config.GPGHomeDir, commitAction); err != nil {
 		return err