docker: setup bitcoind docker image in the docker compose yaml file

docker/bitcoind/start-bitcoind.sh

@@ -0,0 +1,75 @@
+#!/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 the 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 to override it during 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.
+
+# This password is for testing and it is equivalent to `devpass`.
+# It is generated from (Note: It is fully deterministic, yet the random salt
+# generated by the script ensures that the resulting hash is always unique.):
+# https://github.com/bitcoin/bitcoin/blob/master/share/rpcauth/rpcauth.py
+DEFAULT_PASSWORD='22d3dd348a42d7f040487887b0ea6cc7$79ce831819539c78537884f85b65a09e15b079d79eb8f99447ea9b0a58fa66a6'
+
+RPCAUTH=$(set_default "$RPCAUTH" "devuser:$DEFAULT_PASSWORD")
+NETWORK=$(set_default "$NETWORK" "regtest")
+DEBUG=$(set_default "$BITCOIND_DEBUG" "1")
+
+PARAMS=""
+if [ "$NETWORK" != "mainnet" ]; then
+   PARAMS="-$NETWORK"
+fi
+
+PARAMS=$(echo $PARAMS \
+    "-debug"="$DEBUG" \
+    "-rpcauth"="$RPCAUTH" \
+    "-datadir"="/data" \
+    "-debuglogfile"="/data/debug.log" \
+    "-rpcbind"="0.0.0.0" \
+    "-rpcallowip"="0.0.0.0/0" \
+    "-zmqpubrawblock"="tcp://0.0.0.0:28332" \
+    "-zmqpubrawtx"="tcp://0.0.0.0:28333" \
+    "-txindex"
+)
+
+# Add user parameters to the command.
+PARAMS="$PARAMS $@"
+
+# Print command and start bitcoin node.
+echo "Command: bitcoind $PARAMS"
+exec bitcoind $PARAMS