util: add ensure_dir_exists parameter to write_file (#443)

This allows us to disable the `ensure_dir` call when it isn't
appropriate.

1 files changed, 14 insertions, 2 deletions

diff --git a/cloudinit/util.py b/cloudinit/util.py
index 23d24c4c..81369652 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -1800,7 +1800,15 @@ def chmod(path, mode):
             os.chmod(path, real_mode)
 
 
-def write_file(filename, content, mode=0o644, omode="wb", preserve_mode=False):
+def write_file(
+    filename,
+    content,
+    mode=0o644,
+    omode="wb",
+    preserve_mode=False,
+    *,
+    ensure_dir_exists=True
+):
     """
     Writes a file with the given content and sets the file mode as specified.
     Restores the SELinux context if possible.
@@ -1811,6 +1819,9 @@ def write_file(filename, content, mode=0o644, omode="wb", preserve_mode=False):
     @param omode: The open mode used when opening the file (w, wb, a, etc.)
     @param preserve_mode: If True and `filename` exists, preserve `filename`s
                           current mode instead of applying `mode`.
+    @param ensure_dir_exists: If True (the default), ensure that the directory
+                              containing `filename` exists before writing to
+                              the file.
     """
 
     if preserve_mode:
@@ -1820,7 +1831,8 @@ def write_file(filename, content, mode=0o644, omode="wb", preserve_mode=False):
         except OSError:
             pass
 
-    ensure_dir(os.path.dirname(filename))
+    if ensure_dir_exists:
+        ensure_dir(os.path.dirname(filename))
     if 'b' in omode.lower():
         content = encode_text(content)
         write_type = 'bytes'