docker images: add morpho node docker image

docker/morpho.nix

@@ -0,0 +1,32 @@
+{ lib, buildLayeredImage, mkEnv, morpho-node, coreutils, gnused, gnugrep, writeShellScript }:
+let run-morpho-node =
+  writeShellScript "morpho-node" ''
+    set -exuo pipefail
+
+    mkdir -p /tmp
+    cd "$NOMAD_TASK_DIR"
+
+    set +x
+    echo "waiting for $REQUIRED_PEER_COUNT peers"
+    until [ "$(jq -e -r < morpho-topology.json '.[] | length')" -ge "$REQUIRED_PEER_COUNT" ]; do
+      sleep 0.1
+    done
+    set -x
+
+    exec morpho-checkpoint-node \
+          --topology "$NOMAD_TASK_DIR"/morpho-topology.json \
+          --database-path /local/db \
+          --port "$NOMAD_PORT_morpho" \
+          --config "$NOMAD_TASK_DIR"/morpho-config.yaml \
+          --socket-dir "$NOMAD_TASK_DIR/socket" \
+          "$@"
+  '';
+in {
+  morpho = buildLayeredImage {
+    name = "docker.mantis.ws/morpho-node";
+    config = {
+      Entrypoint = [ run-morpho-node ];
+      Env = mkEnv { PATH = lib.makeBinPath [ coreutils gnugrep gnused morpho-node ]; };
+    };
+  };
+}