fix: only read genesis.vkey when it exists

Fixes #107

Author: agaffney

bin/run-node

@@ -44,7 +44,10 @@ CARDANO_SOCKET_PATH=${CARDANO_SOCKET_PATH:-/opt/cardano/ipc/socket}
 CARDANO_TOPOLOGY=${CARDANO_TOPOLOGY:-${CARDANO_CONFIG_BASE}/${CARDANO_NETWORK}/topology.json}
 # mithril
 AGGREGATOR_ENDPOINT=${AGGREGATOR_ENDPOINT:-https://aggregator.release-${CARDANO_NETWORK}.api.mithril.network/aggregator}
-GENESIS_VERIFICATION_KEY=${GENESIS_VERIFICATION_KEY:-$(<${CARDANO_CONFIG_BASE}/${CARDANO_NETWORK}/genesis.vkey)}
+GENESIS_VERIFICATION_KEY_PATH=${GENESIS_VERIFICATION_KEY_PATH:-${CARDANO_CONFIG_BASE}/${CARDANO_NETWORK}/genesis.vkey}
+if [[ -z $GENESIS_VERIFICATION_KEY && -f $GENESIS_VERIFICATION_KEY_PATH ]]; then
+	GENESIS_VERIFICATION_KEY=$(<${GENESIS_VERIFICATION_KEY_PATH})
+fi
 SNAPSHOT_DIGEST=${SNAPSHOT_DIGEST:-latest}
 RESTORE_SNAPSHOT=${RESTORE_SNAPSHOT:-true}