dgoss: add flag for debugging (#998)

extras/dgoss/README.md

@@ -80,6 +80,21 @@ This allows the user to leverage the `goss add|autoadd` commands to write tests
 
 The following environment variables can be set to change the behavior of dgoss.
 
+#### DEBUG
+
+Enables debug output of `dgoss`.
+
+When running in debug mode, the tmp dir with the container output will not be cleaned up.
+
+Note: Debug output of `dgoss` is from `dgoss` shell script and not debug output of `goss`
+(`dgoss run -e GOSS_LOGLEVEL=DEBUG jenkins:alpine`).
+
+**Default:** empty
+
+**Example:**
+
+`DEBUG=true dgoss run jenkins:alpine`
+
 #### GOSS_PATH
 
 Location of the goss binary to use. (Default: `$(which goss)`)

extras/dgoss/dgoss

@@ -1,6 +1,7 @@
 #!/bin/bash
 
 set -e
+[ "$DEBUG" ] && set -x
 
 USAGE="USAGE: $(basename "$0") [run|edit] <docker_run_params>"
 GOSS_FILES_PATH="${GOSS_FILES_PATH:-.}"
@@ -22,7 +23,7 @@ cleanup() {
     if [ -n "$CONTAINER_LOG_OUTPUT" ]; then
         cp "$tmp_dir/docker_output.log" "$CONTAINER_LOG_OUTPUT"
     fi
-    rm -rf "$tmp_dir"
+    [ "$DEBUG" ] || rm -rf "$tmp_dir"
     if [[ $id ]];then
         info "Deleting container"
         $CONTAINER_RUNTIME rm -vf "$id" > /dev/null