update-grid-servers

#!/usr/bin/env nix-shell
#!nix-shell -i bash -p jp

#
# Tell all servers belonging to a certain grid that they should update
# themselves to the latest configuration associated with that grid.
#

set -euxo pipefail

# Get the path to the ssh key which authorizes us to deliver this
# notification.
DEPLOY_KEY=$1
shift

# Get the name of the grid to which we're going to deliver notification.  This
# corresponds to the name of one of the directories in the top-level `morph`
# directory.
GRIDNAME=$1
shift

# Tell one server to update itself.
update_one_node() {
    deploy_key=$1
    shift

    node=$1
    shift

    ssh -i "${deploy_key}" "deployment@${node}"
}

# Tell all servers belonging to one grid to update themselves.
update_grid_nodes() {
    deploy_key=$1
    shift

    gridname=$1
    shift

    # Find the names of all hosts that belong to this grid.  This list includes
    # one extra string, "network", which is morph configuration stuff and we need
    # to filter out later.
    nodes=$(nix eval --json '(builtins.attrNames (import ./morph/${gridname}/grid.nix))')

    # Tell every server in the network to update itself.
    for node in ${nodes}; do
	if [ "${node}" = "network" ]; then
	    # This isn't a server, it's part of the morph configuration.
	    continue
	fi
	update_one_node "${deploy_key}" "${node}"
    fi
}

update_grid_nodes "${DEPLOY_KEY}" "${GRIDNAME}"