Changes how the environment variables from a file are set and expands to allow any to be set this way

docker/env-from-file.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+# Scans the environment variables for those with the suffix _FILE
+# When located, checks the file exists, and exports the contents
+# of the file as the same name, minus the suffix
+# This allows the use of Docker secrets or mounted files
+# to fill in any of the settings configurable via environment
+# variables
+
+set -eu
+
+for line in $(printenv)
+do
+	# Extract the name of the environment variable
+	env_name=${line%%=*}
+	# Check if it ends in "_FILE"
+	if [[ ${env_name} == *_FILE ]]; then
+		# Extract the value of the environment
+		env_value=${line#*=}
+
+		# Check the file exists
+		if [[ -f ${env_value} ]]; then
+
+			# Trim off the _FILE suffix
+			non_file_env_name=${env_name%"_FILE"}
+			echo "Setting ${non_file_env_name} from file"
+
+			# Reads the value from th file
+			val="$(< "${!env_name}")"
+
+			# Sets the normal name to the read file contents
+			export "${non_file_env_name}"="${val}"
+
+		else
+			echo "File ${env_value} doesn't exist"
+			exit 1
+		fi
+	fi
+done