Add LND Unlocking script

build/lnd-unlock/Dockerfile

@@ -0,0 +1,11 @@
+FROM alpine:3.10
+
+RUN apk add --no-cache curl jq
+
+RUN mkdir /lnd/
+
+COPY unlock.sh /bin/unlock
+
+RUN chmod +x /bin/unlock
+
+ENTRYPOINT ["unlock"]

build/lnd-unlock/unlock.sh

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+#!/bin/sh
+
+HOST=lnd:8080
+TLS_CERT=/lnd/tls.cert
+MACAROON="$(xxd -p /run/secrets/lnd-admin | tr -d '\n')"
+PASS="$(cat /run/secrets/lnd-password | tr -d '\n' | base64 | tr -d '\n')"
+UNLOCK_PAYLOAD="$(jq -nc --arg wallet_password ${PASS} '{$wallet_password}')"
+
+lncurl() {
+	url_path=$1
+	data=$2
+
+	curl  --fail  --silent  --show-error  \
+	  --cacert "${TLS_CERT}"  \
+	  --header "Grpc-Metadata-macaroon: ${MACAROON}"  \
+	  --data "${data}"  \
+	  "https://${HOST}/v1/${url_path}"
+}
+
+while true; do
+	# First make sure that lnd:8080 port is open
+	while ! nc -z lnd 8080; do
+		>&2 echo "Waiting for ${HOST} port to open…"
+		sleep 3
+	done
+	>&2 echo "Port ${HOST} is open"
+
+	# Wait a bit more in case the port was just opened
+	sleep 1
+
+	>&2 echo "Trying ${HOST}/getinfo…"
+	INFO=$(lncurl getinfo)
+	if [ "$?" = "0" ]; then
+		>&2 echo "Response: ${INFO}"
+		alias="$(echo "${INFO}" | jq '.alias')"
+		>&2 echo "Wallet for ${alias} unlocked!"
+		exit 0
+	fi
+	>&2 echo "${HOST}/getinfo FAILED, out=${INFO}"
+
+	>&2 echo "Trying ${HOST}/unlockwallet…"
+	RESULT=$(lncurl unlockwallet "${UNLOCK_PAYLOAD}")
+	>&2 echo "${HOST}/unlockwallet completed with: exit-code=$?, out=${RESULT}"
+
+	sleep 16
+done