[management] optimize posture cache (#8366)

shared/management/networkmap/nmdata/posture_nb_version.go

@@ -2,6 +2,7 @@ package nmdata
 
 import (
 	"strings"
+	"sync"
 
 	"github.com/hashicorp/go-version"
 )
@@ -9,27 +10,26 @@ import (
 // NBVersionCheck is the slim twin of posture.NBVersionCheck.
 type NBVersionCheck struct {
 	MinVersion string
+
+	constraintOnce sync.Once
+	constraint     version.Constraints
+	constraintErr  error
 }
 
 func (n *NBVersionCheck) check(peer *Peer) (bool, error) {
-	return meetsMinVersion(n.MinVersion, peer.Meta.WtVersion)
-}
-
-func meetsMinVersion(minVer, peerVer string) (bool, error) {
-	peerVer = sanitizeVersion(peerVer)
-	minVer = sanitizeVersion(minVer)
-
-	peerNBVer, err := version.NewVersion(peerVer)
+	peerNBVer, err := version.NewVersion(sanitizeVersion(peer.Meta.WtVersion))
 	if err != nil {
 		return false, err
 	}
 
-	constraints, err := version.NewConstraint(">= " + minVer)
-	if err != nil {
-		return false, err
+	n.constraintOnce.Do(func() {
+		n.constraint, n.constraintErr = version.NewConstraint(">= " + sanitizeVersion(n.MinVersion))
+	})
+	if n.constraintErr != nil {
+		return false, n.constraintErr
 	}
 
-	return constraints.Check(peerNBVer), nil
+	return n.constraint.Check(peerNBVer), nil
 }
 
 func sanitizeVersion(v string) string {