sudo setfacl -dR -m u:teamcity:rwx /var/www/myapp

getfacl /var/www/myapp
getfacl: Removing leading '/' from absolute path names
# file: var/www/app1
# owner: root
# group: root
user::rwx
group::r-x
other::r-x
default:user::rwx
default:user:teamcity:rwx
default:group::r-x
default:mask::rwx
default:other::r-x

cp: cannot create regular file '/var/www/myapp/appsettings.json': Permission denied

sudo runuser -l teamcity -c 'cd /opt/jetbrains/TeamCity/buildAgent/work/f5f9b0bd3b4556c2; cp -Rf appsettings.json /var/www/myapp/'