Simplify env _FILE script, tweak inline docs

run.sh

@@ -46,24 +46,18 @@ if [ ! -z ${GF_AWS_PROFILES+x} ]; then
     chmod 600 "$GF_PATHS_HOME/.aws/credentials"
 fi
 
-# Convert all grafana variables which names ends with _FILE into the content of
-# the file that they point at and using the name without the trailing _FILE.
+# Convert all environment variables with names ending in _FILE into the content of
+# the file that they point at and use the name without the trailing _FILE.
 # This can be used to carry in Docker secrets.
-for VAR in $(env); do
-    if [ -n "$(echo $VAR | grep -E '^GF_' | grep -E '_FILE=')" ]; then
-        VAR_NAME_FILE=$(echo "$VAR" | sed -r "s/([^=]*)=.*/\1/g")
-        VAR_NAME=$(echo "$VAR_NAME_FILE" | sed -r "s/(.*)_FILE$/\1/g")
-        if [ "${!VAR_NAME}" ] && [ "${!VAR_NAME_FILE}" ]; then
-            echo >&2 "ERROR: Both $VAR_NAME and $VAR_NAME_FILE are set (but are exclusive)"
-            exit 1
-        fi
-        if [ "${!VAR_NAME_FILE}" ]; then
-            echo "Getting secret $VAR_NAME from ${!VAR_NAME_FILE}"
-            VAL="$(< "${!VAR_NAME_FILE}")"
-            export "$VAR_NAME"="$VAL"
-            unset "$VAR_NAME_FILE"
-        fi
+for VAR_NAME in $(env | grep '^GF_[^=]\+_FILE=.\+' | sed -r "s/([^=]*)_FILE=.*/\1/g"); do
+    VAR_NAME_FILE="$VAR_NAME"_FILE
+    if [ "${!VAR_NAME}" ]; then
+        echo >&2 "ERROR: Both $VAR_NAME and $VAR_NAME_FILE are set (but are exclusive)"
+        exit 1
     fi
+    echo "Getting secret $VAR_NAME from ${!VAR_NAME_FILE}"
+    export "$VAR_NAME"="$(< "${!VAR_NAME_FILE}")"
+    unset "$VAR_NAME_FILE"
 done
 
 export HOME="$GF_PATHS_HOME"
@@ -85,4 +79,4 @@ exec grafana-server                                         \
   cfg:default.paths.data="$GF_PATHS_DATA"                   \
   cfg:default.paths.logs="$GF_PATHS_LOGS"                   \
   cfg:default.paths.plugins="$GF_PATHS_PLUGINS"             \
-  cfg:default.paths.provisioning="$GF_PATHS_PROVISIONING"
+  cfg:default.paths.provisioning="$GF_PATHS_PROVISIONING"