Add structure for new exec session tracking to DB

As part of the rework of exec sessions, we need to address them
independently of containers. In the new API, we need to be able
to fetch them by their ID, regardless of what container they are
associated with. Unfortunately, our existing exec sessions are
tied to individual containers; there's no way to tell what
container a session belongs to and retrieve it without getting
every exec session for every container.

This adds a pointer to the container an exec session is
associated with to the database. The sessions themselves are
still stored in the container.

Exec-related APIs have been restructured to work with the new
database representation. The originally monolithic API has been
split into a number of smaller calls to allow more fine-grained
control of lifecycle. Support for legacy exec sessions has been
retained, but in a deprecated fashion; we should remove this in
a few releases.

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

1 files changed, 27 insertions, 0 deletions

diff --git a/libpod/boltdb_state_internal.go b/libpod/boltdb_state_internal.go
index 3f09305f5..1c4c9e12d 100644
--- a/libpod/boltdb_state_internal.go
+++ b/libpod/boltdb_state_internal.go
@@ -24,6 +24,7 @@ const (
 	allPodsName       = "allPods"
 	volName           = "vol"
 	allVolsName       = "allVolumes"
+	execName          = "exec"
 	runtimeConfigName = "runtime-config"
 
 	configName         = "config"
@@ -54,6 +55,7 @@ var (
 	allPodsBkt       = []byte(allPodsName)
 	volBkt           = []byte(volName)
 	allVolsBkt       = []byte(allVolsName)
+	execBkt          = []byte(execName)
 	runtimeConfigBkt = []byte(runtimeConfigName)
 
 	configKey          = []byte(configName)
@@ -339,6 +341,14 @@ func getAllVolsBucket(tx *bolt.Tx) (*bolt.Bucket, error) {
 	return bkt, nil
 }
 
+func getExecBucket(tx *bolt.Tx) (*bolt.Bucket, error) {
+	bkt := tx.Bucket(execBkt)
+	if bkt == nil {
+		return nil, errors.Wrapf(define.ErrDBBadConfig, "exec bucket not found in DB")
+	}
+	return bkt, nil
+}
+
 func getRuntimeConfigBucket(tx *bolt.Tx) (*bolt.Bucket, error) {
 	bkt := tx.Bucket(runtimeConfigBkt)
 	if bkt == nil {
@@ -787,6 +797,23 @@ func (s *BoltState) removeContainer(ctr *Container, pod *Pod, tx *bolt.Tx) error
 		}
 	}
 
+	// Does the container have exec sessions?
+	ctrExecSessionsBkt := ctrExists.Bucket(execBkt)
+	if ctrExecSessionsBkt != nil {
+		sessions := []string{}
+		err = ctrExecSessionsBkt.ForEach(func(id, value []byte) error {
+			sessions = append(sessions, string(id))
+
+			return nil
+		})
+		if err != nil {
+			return err
+		}
+		if len(sessions) > 0 {
+			return errors.Wrapf(define.ErrExecSessionExists, "container %s has active exec sessions: %s", ctr.ID(), strings.Join(sessions, ", "))
+		}
+	}
+
 	// Does the container have dependencies?
 	ctrDepsBkt := ctrExists.Bucket(dependenciesBkt)
 	if ctrDepsBkt == nil {