Added support for reading the default password from a file (i.e. docker secret)

Author: vovimayhem

alpine/docker-entrypoint.sh

@@ -1,6 +1,30 @@
 #!/bin/bash
 set -eu
 
+# usage: file_env VAR [DEFAULT]
+#    ie: file_env 'XYZ_DB_PASSWORD' 'example'
+# (will allow for "$XYZ_DB_PASSWORD_FILE" to fill in the value of
+#  "$XYZ_DB_PASSWORD" from a file, especially for Docker's secrets feature)
+file_env() {
+	local var="$1"
+	local fileVar="${var}_FILE"
+	local def="${2:-}"
+	if [ "${!var:-}" ] && [ "${!fileVar:-}" ]; then
+		echo >&2 "error: both $var and $fileVar are set (but are exclusive)"
+		exit 1
+	fi
+	local val="$def"
+	if [ "${!var:-}" ]; then
+		val="${!var}"
+	elif [ "${!fileVar:-}" ]; then
+		val="$(< "${!fileVar}")"
+	fi
+	export "$var"="$val"
+	unset "$fileVar"
+}
+
+file_env 'RABBITMQ_DEFAULT_PASS'
+
 # allow the container to be started with `--user`
 if [[ "$1" == rabbitmq* ]] && [ "$(id -u)" = '0' ]; then
 	if [ "$1" = 'rabbitmq-server' ]; then

debian/docker-entrypoint.sh

@@ -1,6 +1,30 @@
 #!/bin/bash
 set -eu
 
+# usage: file_env VAR [DEFAULT]
+#    ie: file_env 'XYZ_DB_PASSWORD' 'example'
+# (will allow for "$XYZ_DB_PASSWORD_FILE" to fill in the value of
+#  "$XYZ_DB_PASSWORD" from a file, especially for Docker's secrets feature)
+file_env() {
+	local var="$1"
+	local fileVar="${var}_FILE"
+	local def="${2:-}"
+	if [ "${!var:-}" ] && [ "${!fileVar:-}" ]; then
+		echo >&2 "error: both $var and $fileVar are set (but are exclusive)"
+		exit 1
+	fi
+	local val="$def"
+	if [ "${!var:-}" ]; then
+		val="${!var}"
+	elif [ "${!fileVar:-}" ]; then
+		val="$(< "${!fileVar}")"
+	fi
+	export "$var"="$val"
+	unset "$fileVar"
+}
+
+file_env 'RABBITMQ_DEFAULT_PASS'
+
 # allow the container to be started with `--user`
 if [[ "$1" == rabbitmq* ]] && [ "$(id -u)" = '0' ]; then
 	if [ "$1" = 'rabbitmq-server' ]; then