Merge pull request #872 from ahgraber/master

Add Docker secrets

docker/rootfs/etc/cont-init.d/.gitignore

@@ -1,2 +1,3 @@
 *
 !.gitignore
+!*.sh

docker/rootfs/etc/cont-init.d/01_s6-secret-init.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/with-contenv bash
+# ref: https://github.com/linuxserver/docker-baseimage-alpine/blob/master/root/etc/cont-init.d/01-envfile
+
+# in s6, environmental variables are written as text files for s6 to monitor
+# seach through full-path filenames for files ending in "__FILE"
+for FILENAME in $(find /var/run/s6/container_environment/ | grep "__FILE$"); do
+    echo "[secret-init] Evaluating ${FILENAME##*/} ..."
+
+    # set SECRETFILE to the contents of the full-path textfile
+    SECRETFILE=$(cat ${FILENAME})
+    # SECRETFILE=${FILENAME}
+    # echo "[secret-init] Set SECRETFILE to ${SECRETFILE}"  # DEBUG - rm for prod!
+
+    # if SECRETFILE exists / is not null
+    if [[ -f ${SECRETFILE} ]]; then
+        # strip the appended "__FILE" from environmental variable name ...
+        STRIPFILE=$(echo ${FILENAME} | sed "s/__FILE//g") 
+        # echo "[secret-init] Set STRIPFILE to ${STRIPFILE}"  # DEBUG - rm for prod!
+        
+        # ... and set value to contents of secretfile
+        # since s6 uses text files, this is effectively "export ..."
+        printf $(cat ${SECRETFILE}) > ${STRIPFILE}
+        # echo "[secret-init] Set ${STRIPFILE##*/} to $(cat ${STRIPFILE})"  # DEBUG - rm for prod!"
+        echo "[secret-init] Success! ${STRIPFILE##*/} set from ${FILENAME##*/}"
+
+    else
+        echo "[secret-init] cannot find secret in ${FILENAME}"
+    fi
+done