better config file management

bitcoind.run

@@ -5,11 +5,21 @@ export HOME="/var/lib/bitcoind"
 # gen random pw for rpc server
 RANDOMPW=$(openssl rand -hex 10)
 
-if [[ ! -e $HOME/bitcoin.conf ]]; then
+# if password is specified, overwrite config file
+if [[ "$BITCOIND_RPCPASSWORD" != "" ]]; then
 cat <<EOF > $HOME/bitcoin.conf
 rpcuser=${BITCOIND_RPCUSER:-rpcuser}
 rpcpassword=${BITCOIND_RPCPASSWORD:-$RANDOMPW}
 EOF
+else
+# if using randomly generated pw, do not overwrite config
+# if it already exists
+if [[ ! -e $HOME/bitcoin.conf ]]; then
+cat <<EOF > $HOME/bitcoin.conf
+rpcuser=${BITCOIND_RPCUSER:-rpcuser}
+rpcpassword=$RANDOMPW
+EOF
+fi
 fi
 
 # SECURITY this puts the rpc password into the container log