cord-776 create build / runtime containers for autmation uservices

Change-Id: I246973192adef56a250ffe93a5f65fff488840c1
diff --git a/automation/vendor/github.com/juju/utils/relativeurl.go b/automation/vendor/github.com/juju/utils/relativeurl.go
new file mode 100644
index 0000000..b70f1d5
--- /dev/null
+++ b/automation/vendor/github.com/juju/utils/relativeurl.go
@@ -0,0 +1,62 @@
+// Copyright 2016 Canonical Ltd.
+// Licensed under the LGPLv3, see LICENCE file for details.
+
+package utils
+
+import (
+	"strings"
+
+	"github.com/juju/errors"
+)
+
+// RelativeURLPath returns a relative URL path that is lexically
+// equivalent to targpath when interpreted by url.URL.ResolveReference.
+// On success, the returned path will always be non-empty and relative
+// to basePath, even if basePath and targPath share no elements.
+//
+// It is assumed that both basePath and targPath are normalized
+// (have no . or .. elements).
+//
+// An error is returned if basePath or targPath are not absolute paths.
+func RelativeURLPath(basePath, targPath string) (string, error) {
+	if !strings.HasPrefix(basePath, "/") {
+		return "", errors.New("non-absolute base URL")
+	}
+	if !strings.HasPrefix(targPath, "/") {
+		return "", errors.New("non-absolute target URL")
+	}
+	baseParts := strings.Split(basePath, "/")
+	targParts := strings.Split(targPath, "/")
+
+	// For the purposes of dotdot, the last element of
+	// the paths are irrelevant. We save the last part
+	// of the target path for later.
+	lastElem := targParts[len(targParts)-1]
+	baseParts = baseParts[0 : len(baseParts)-1]
+	targParts = targParts[0 : len(targParts)-1]
+
+	// Find the common prefix between the two paths:
+	var i int
+	for ; i < len(baseParts); i++ {
+		if i >= len(targParts) || baseParts[i] != targParts[i] {
+			break
+		}
+	}
+	dotdotCount := len(baseParts) - i
+	targOnly := targParts[i:]
+	result := make([]string, 0, dotdotCount+len(targOnly)+1)
+	for i := 0; i < dotdotCount; i++ {
+		result = append(result, "..")
+	}
+	result = append(result, targOnly...)
+	result = append(result, lastElem)
+	final := strings.Join(result, "/")
+	if final == "" {
+		// If the final result is empty, the last element must
+		// have been empty, so the target was slash terminated
+		// and there were no previous elements, so "."
+		// is appropriate.
+		final = "."
+	}
+	return final, nil
+}