refactor(uptane): Refactor the Update methods

pkg/config/remote/uptane/client.go

@@ -18,7 +18,6 @@ import (
 
 	rdata "github.com/DataDog/datadog-agent/pkg/config/remote/data"
 	"github.com/DataDog/datadog-agent/pkg/proto/pbgo"
-	"github.com/DataDog/datadog-agent/pkg/util/log"
 )
 
 // Client is an uptane client
@@ -70,43 +69,35 @@ func NewClient(cacheDB *bbolt.DB, cacheKey string, orgID int64) (*Client, error)
 	return c, nil
 }
 
-func (c *Client) rollback(err error) {
-	c.transactionalStore.rollback()
+// Update updates the uptane client and rollbacks in case of error
+func (c *Client) Update(response *pbgo.LatestConfigsResponse) error {
+	c.Lock()
+	defer c.Unlock()
+	c.cachedVerify = false
+
+	err := c.update(response)
 	if err != nil {
+		c.transactionalStore.rollback()
 		c.configRemoteStore = newRemoteStoreConfig(c.targetStore)
 		c.directorRemoteStore = newRemoteStoreDirector(c.targetStore)
 		c.configTUFClient = client.NewClient(c.configLocalStore, c.configRemoteStore)
 		c.directorTUFClient = client.NewClient(c.directorLocalStore, c.directorRemoteStore)
+		return err
 	}
+	return c.transactionalStore.commit()
 }
 
-// Update updates the uptane client
-func (c *Client) Update(response *pbgo.LatestConfigsResponse) error {
-	c.Lock()
-	defer c.Unlock()
-	c.cachedVerify = false
-	var err error
-
-	// in case the commit is successful it is a no-op.
-	// the defer is present to be sure a transaction is never left behind.
-	defer func() { c.rollback(err) }()
-
-	err = c.updateRepos(response)
+// update updates the uptane client
+func (c *Client) update(response *pbgo.LatestConfigsResponse) error {
+	err := c.updateRepos(response)
 	if err != nil {
 		return err
 	}
 	err = c.pruneTargetFiles()
 	if err != nil {
 		return err
 	}
-	err = c.verify()
-	if err != nil {
-		return err
-	}
-	log.Infof("committing")
-
-	err = c.transactionalStore.commit()
-	return err
+	return c.verify()
 }
 
 // TargetsCustom returns the current targets custom of this uptane client

pkg/config/remote/uptane/remote_store.go

@@ -58,7 +58,7 @@ func (s *remoteStore) latestVersion(r role) uint64 {
 	return latestVersion
 }
 
-// GetMeta implements go-tuf's RemoteStore.<
+// GetMeta implements go-tuf's RemoteStore.GetMeta
 // See https://pkg.go.dev/github.com/theupdateframework/go-tuf/client#RemoteStore
 func (s *remoteStore) GetMeta(path string) (io.ReadCloser, int64, error) {
 	metaPath, err := parseMetaPath(path)