Implement lock for aws-vault for better parallelization (#426)

* Implement lock for aws-vault for better parallelization

Add locking mechanism to prevent concurrent aws-vault processes.

* Update startupscript/aws/configure-aws-vault.sh

---------

Co-authored-by: David Shen <2984600+pantherman594@users.noreply.github.com>

Author: NBBense

startupscript/aws/configure-aws-vault.sh

@@ -38,6 +38,13 @@ export AWS_VAULT_FILE_PASSPHRASE=""
 # do not use.
 export DBUS_SESSION_BUS_ADDRESS="/dev/null"
 
+if [ "\$1" = "export" ]; then
+  # Use a lock to prevent multiple aws-vault processes from attempting to
+  # retrieve credentials from wb at the same time
+  exec 200>/var/lock/aws-vault.lock
+  flock -w 30 200 || { echo "Failed to acquire lock for aws-vault export" >&2; exit 1; }
+fi
+
 exec "${AWS_VAULT_BINARY_PATH}" "\$@"
 EOF