Unconditionally retrieve pod names via API

The ListContainers API previously had a Pod parameter, which
determined if pod name was returned (but, notably, not Pod ID,
which was returned unconditionally). This was fairly confusing,
so we decided to deprecate/remove the parameter and return it
unconditionally.

To do this without serious performance implications, we need to
avoid expensive JSON decodes of pod configuration in the DB. The
way our Bolt tables are structured, retrieving name given ID is
actually quite cheap, but we did not expose this via the Libpod
API. Add a new GetName API to do this.

Fixes #7214

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

1 files changed, 30 insertions, 0 deletions

diff --git a/libpod/in_memory_state.go b/libpod/in_memory_state.go
index 2ac05e88d..0de25a6ef 100644
--- a/libpod/in_memory_state.go
+++ b/libpod/in_memory_state.go
@@ -106,6 +106,36 @@ func (s *InMemoryState) SetNamespace(ns string) error {
 	return nil
 }
 
+// GetName retrieves the name associated with a given ID.
+// Works with both Container and Pod IDs.
+func (s *InMemoryState) GetName(id string) (string, error) {
+	if id == "" {
+		return "", define.ErrEmptyID
+	}
+
+	var idIndex *truncindex.TruncIndex
+	if s.namespace != "" {
+		nsIndex, ok := s.namespaceIndexes[s.namespace]
+		if !ok {
+			// We have no containers in the namespace
+			// Return false
+			return "", define.ErrNoSuchCtr
+		}
+		idIndex = nsIndex.idIndex
+	} else {
+		idIndex = s.idIndex
+	}
+
+	fullID, err := idIndex.Get(id)
+	if err != nil {
+		if err == truncindex.ErrNotExist {
+			return "", define.ErrNoSuchCtr
+		}
+		return "", errors.Wrapf(err, "error performing truncindex lookup for ID %s", id)
+	}
+	return fullID, nil
+}
+
 // Container retrieves a container from its full ID
 func (s *InMemoryState) Container(id string) (*Container, error) {
 	if id == "" {