lnd.xprv/docker/btcd/start-btcctl.sh

#!/usr/bin/env bash

# exit from script if error was raised.
set -e

# error function is used within a bash function in order to send the error
# message directly to the stderr output and exit.
error() {
    echo "$1" > /dev/stderr
    exit 0
}

# return is used within bash function in order to return the value.
return() {
    echo "$1"
}

# set_default function gives the ability to move the setting of default
# env variable from docker file to the script thereby giving the ability to the
# user override it durin container start.
set_default() {
    # docker initialized env variables with blank string and we can't just
    # use -z flag as usually.
    BLANK_STRING='""'

    VARIABLE="$1"
    DEFAULT="$2"

    if [[ -z "$VARIABLE" || "$VARIABLE" == "$BLANK_STRING" ]]; then

        if [ -z "$DEFAULT" ]; then
            error "You should specify default variable"
        else
            VARIABLE="$DEFAULT"
        fi
    fi

   return "$VARIABLE"
}

# Set default variables if needed.
RPCUSER=$(set_default "$RPCUSER" "devuser")
RPCPASS=$(set_default "$RPCPASS" "devpass")
BITCOIN_NETWORK=$(set_default "$BITCOIN_NETWORK" "simnet")

btcctl \
    "--$BITCOIN_NETWORK" \
    --rpccert="/rpc/rpc.cert" \
    --rpcuser="$RPCUSER" \
    --rpcpass="$RPCPASS" \
    --rpcserver="rpcserver" \
    "$@"