[Libguestfs] [PATCH v3 5/6] v2v: utils: Add utility functions for running external Python code.

[Richard W.M. Jones]

---
 v2v/utils.ml  | 23 +++++++++++++++++++++++
 v2v/utils.mli | 11 +++++++++++
 2 files changed, 34 insertions(+)

diff --git a/v2v/utils.ml b/v2v/utils.ml
index 1ceba94cd..66ca269b1 100644
--- a/v2v/utils.ml
+++ b/v2v/utils.ml
@@ -196,3 +196,26 @@ let find_file_in_tar tar filename =
     )
   in
   loop lines
+
+let run_python ?(python = "python") code =
+  (* In debug mode output the python code into the log. *)
+  debug "running python code using ‘%s’:\n%s" python code;
+
+  (* Write the Python code to a temporary file so we don't have to
+   * quote things.
+   *)
+  let filename, chan = Filename.open_temp_file "py" ".py" in
+  output_string chan code;
+  close_out chan;
+
+  let cmd = sprintf "%s %s" (quote python) (quote filename) in
+  let lines = external_command cmd in
+  Unix.unlink filename;
+  lines
+
+let py_quote str =
+  let str = String.replace str "\\" "\\\\" in
+  let str = String.replace str "'" "\\'" in
+  "'''" ^ str ^ "'''"
+
+let py_bool = function true -> "True" | false -> "False"
diff --git a/v2v/utils.mli b/v2v/utils.mli
index 34402e28f..3a8dfd437 100644
--- a/v2v/utils.mli
+++ b/v2v/utils.mli
@@ -61,3 +61,14 @@ val find_file_in_tar : string -> string -> int64 * int64
 
     Function raises [Not_found] if there is no such file inside [tar] and
     [Failure] if there is any error parsing the tar output. *)
+
+val run_python : ?python:string -> string -> string list
+(** Run a snippet of Python code, and collect the output.
+
+    On failure this raises an error. *)
+
+val py_quote : string -> string
+(** Return a fully quoted Python string literal. *)
+
+val py_bool : bool -> string
+(** Return "True" or "False". *)
-- 
2.13.2