log.py: Add utilities, better list-support in slog_m()

- Add functions: append_to_prefix(),
  remove_from_prefix() set_filename_length()
- Make slog_m() log one list item per line
- Add console_color_chars(prio)

Signed-off-by: Jan Lindemann <jan@janware.com>

tools/python/jwutils/log.py

@@ -45,6 +45,8 @@ f_color              = 'color'
 f_default            = [ f_position, f_stderr, f_prio, f_color ]
 
 _flags               = set(f_default)
+_log_prefix          = ''
+_file_name_len       = 20
 
 _short_prio_str      = {
     EMERG            : '<Y>',
@@ -81,6 +83,9 @@ def slog_m(prio, *args, **kwargs): # export
     if len(args):
         margs = ''
         for a in args:
+            if isinstance(a, list):
+                margs += '\n'.join([str(elem) for elem in a])
+                continue
             margs += ' ' + str(a)
     caller = get_caller_pos(1)
     for line in margs[1:].split('\n'):
@@ -103,11 +108,13 @@ def slog(prio, *args, **kwargs): # export
             name, line = kwargs['caller']
         else:
             name, line = get_caller_pos(1)
-        msg += misc.pad(name, 20) + '[' + misc.pad(str(line), 4, True) + ']'
+        msg += misc.pad(name, _file_name_len) + '[' + misc.pad(str(line), 4, True) + ']'
 
     if f_color in _flags:
         color_on, color_off = _prio_colors[prio]
 
+    msg += _log_prefix
+
     if len(args):
         margs = ''
         for a in args:
@@ -190,3 +197,26 @@ def set_flags(flags_): # export
     #date
     #pid
     #highlight_first_error
+
+def append_to_prefix(prefix): # export
+    global _log_prefix
+    r = _log_prefix
+    if prefix:
+        _log_prefix += prefix
+    return r
+
+def remove_from_prefix(count): # export
+    global _log_prefix
+    r = _log_prefix
+    _log_prefix = _log_prefix[:-count]
+    return r
+
+def set_filename_length(l): # export
+    global _file_name_len
+    r = _file_name_len
+    if l:
+        _file_name_len = l
+    return r
+
+def console_color_chars(prio): # export
+    return _prio_colors[prio]