New python_pgm_template program.

This template can be used as a source to create new stand-alone python programs.

Change-Id: I86a1fb75387f4141d0522e556f20a233785a6c0f
Signed-off-by: Michael Walsh <micwalsh@us.ibm.com>
diff --git a/bin/python_pgm_template b/bin/python_pgm_template
new file mode 100644
index 0000000..fe32f67
--- /dev/null
+++ b/bin/python_pgm_template
@@ -0,0 +1,141 @@
+#!/usr/bin/env python
+
+r"""
+python_pgm_template: Copy this template as a base to get a start on a python
+program.  You may remove any generic comments (like this one).
+"""
+
+import sys
+
+# python puts the program's directory path in sys.path[0].  In other words,
+# the user ordinarily has no way to override python's choice of a module from
+# its own dir.  We want to have that ability in our environment.  However, we
+# don't want to break any established python modules that depend on this
+# behavior.  So, we'll save the value from sys.path[0], delete it, import our
+# modules and then restore sys.path to its original value.
+
+save_path_0 = sys.path[0]
+del sys.path[0]
+
+from gen_arg import *
+from gen_print import *
+from gen_valid import *
+
+# Restore sys.path[0].
+sys.path.insert(0, save_path_0)
+
+###############################################################################
+# Create parser object to process command line parameters and args.
+
+# Create parser object.
+parser = argparse.ArgumentParser(
+    usage='%(prog)s [OPTIONS]',
+    description="%(prog)s will...",
+    formatter_class=argparse.RawTextHelpFormatter,
+    prefix_chars='-+')
+
+# Create arguments.
+parser.add_argument(
+    '--whatever',
+    help='bla, bla.')
+
+# The stock_list will be passed to gen_get_options.  We populate it with the
+# names of stock parm options we want.  These stock parms are pre-defined by
+# gen_get_options.
+stock_list = [("test_mode", 0), ("quiet", 0), ("debug", 0)]
+###############################################################################
+
+
+###############################################################################
+def exit_function(signal_number=0,
+                  frame=None):
+
+    r"""
+    Execute whenever the program ends normally or with the signals that we
+    catch (i.e. TERM, INT).
+    """
+
+    dprint_executing()
+    dprint_var(signal_number)
+
+    # Your cleanup code here.
+
+    qprint_pgm_footer()
+
+###############################################################################
+
+
+###############################################################################
+def signal_handler(signal_number,
+                   frame):
+
+    r"""
+    Handle signals.  Without a function to catch a SIGTERM or SIGINT, our
+    program would terminate immediately with return code 143 and without
+    calling our exit_function.
+    """
+
+    # Our convention is to set up exit_function with atexit.register() so
+    # there is no need to explicitly call exit_function from here.
+
+    dprint_executing()
+
+    # Calling exit prevents us from returning to the code that was running
+    # when we received the signal.
+    exit(0)
+
+###############################################################################
+
+
+###############################################################################
+def validate_parms():
+
+    r"""
+    Validate program parameters, etc.  Return True or False (i.e. pass/fail)
+    accordingly.
+    """
+
+    # Your validation code here.
+
+    gen_post_validation(exit_function, signal_handler)
+
+    return True
+
+###############################################################################
+
+
+###############################################################################
+def main():
+
+    r"""
+    This is the "main" function.  The advantage of having this function vs
+    just doing this in the true mainline is that you can:
+    - Declare local variables
+    - Use "return" instead of "exit".
+    - Indent 4 chars like you would in any function.
+    This makes coding more consistent, i.e. it's easy to move code from here
+    into a function and vice versa.
+    """
+
+    if not gen_get_options(parser, stock_list):
+        return False
+
+    if not validate_parms():
+        return False
+
+    qprint_pgm_header()
+
+    # Your code here.
+
+    return True
+
+###############################################################################
+
+
+###############################################################################
+# Main
+
+if not main():
+    exit(1)
+
+###############################################################################