net: get missing config variables from config_2g3g

Don't ask the user to copy config_2g3g and manually keep it in sync with
config_2g3g with each change anymore. Instead, let the user config be a
diff on top of config_2g3g.

This is in preparation to adding new variables for use with OsmoBSCNAT.

Change-Id: I5870d39aee8be84c2024f8a2a71ee4a734a4fc7c

net/README

@@ -10,28 +10,55 @@ contributions of any improvements you may have!
 
 === Quick Start
 
-cp config_2g3g config_mine
-$EDITOR config_mine
-# update IP addresses and device names as required
+* Open config_2g3g in a text editor (original config)
+* Open a new file in a text editor (your config)
+* Copy over all lines you want to change in your config and edit them there
+* Your resulting minimal config could look like this:
 
-mkdir my_network
-cd my_network
-../fill_config.py ../config_mine ../templates
+  TERMINAL="tmux"
 
-./run.sh
-# Launches numerous x-terminals with one component running in each.
-# Logs and pcap traces are being taken automatically.
+  ETH_DEV=enp0s25
 
-# hit enter in the original first terminal to tear down all programs.
-# Enter a name to save logs, otherwise all logging will be stored
-# under autolog/<timestamp>
+  TO_RAN_IP="192.168.1.123"
+  TO_RAN_IU_IP="192.168.1.42"
 
-Then possibly modify the config and refresh:
+  MCC=999
+  MNC=99
 
-# tweak config?
-$EDITOR ../config_mine
-../fill_config.py
-# picks up same ../config_mine and ../templates from last time
+  BTS0_IPA_UNIT="1234 0"
+  BTS0_ARFCN=800
+
+* Create a network directory and generate configs:
+
+  $ mkdir my_network
+  $ cd my_network
+  $ ../fill_config.py ../config_mine ../templates
+
+* Run the network:
+
+  $ ./run.sh
+
+  This launches numerous terminals with one component running in each.
+  Logs and pcap traces are being taken automatically.
+
+* Tear down:
+
+  Hit enter in the original first terminal to tear down all programs.
+  Enter a name to save logs, otherwise all logging will be stored
+  under autolog/<timestamp>.
+
+* Regenerate configs:
+
+  Modify your config and regenerate the network configs as follows, the same
+  original config, your config and templates will be used as last time.
+
+  $ $EDITOR ../config_mine
+  $ ../fill_config.py
+
+  ('make regen' also works)
+
+
+=== Advanced usage / more examples
 
 # own templates?
 cp -r ../templates ../templates_mine
@@ -67,7 +94,7 @@ A *directory* contains template files that are filled with specific values by th
 fill_config.py script. See e.g. templates/.
 
 A *file* contains local config items as name=val pairs that are put into the
-templates. See e.g. config_2g3g.
+templates. It is usually a subset of config_2g3g.
 
 The fill_config.py script helps to fill the templates with the config values. Simply
 invoke fill_config.py with a dir argument (templates dir) and a file argument (specific
@@ -77,6 +104,11 @@ temporary files (sockets etc.) should be placed inside this folder.
 If one or both are omitted, the script tries to re-use the most recent paths,
 they were stored in local files '.last_config' and '.last_templates'.
 
+The -o parameter of fill_config.py can be used to supply a different original
+config file than config_2g3g. If it is omitted, the path is read from a
+'.last_config_orig' file inside the network directory if present, and config_2g3g
+is used otherwise.
+
 The result is a complete set of .cfg files that match your local machine and
 network config.
 

net/fill_config.py

@@ -8,7 +8,9 @@ import argparse
 def file_newer(path_a, than_path_b):
   return os.path.getmtime(path_a) > os.path.getmtime(than_path_b)
 
+DEFAULT_ORIG_CONFIG = os.path.normpath(os.path.realpath(__file__) + "/../config_2g3g")
 LAST_LOCAL_CONFIG_FILE = '.last_config'
+LAST_ORIG_CONFIG_FILE = '.last_config_orig'
 LAST_TMPL_DIR = '.last_templates'
 
 parser = argparse.ArgumentParser(description=__doc__,
@@ -18,10 +20,14 @@ parser.add_argument('sources', metavar='SRC', nargs='*',
 parser.add_argument('-s', '--check-stale', dest='check_stale', action='store_true',
                     help='only verify age of generated files vs. config and templates.'
                     ' Exit nonzero when any source file is newer. Do not write anything.')
+parser.add_argument('-o', '--original-config',
+                    help='get missing variables from this file, default is config_2g3g'
+                    ' or the file used previously to fill an existing template dir')
 
 args = parser.parse_args()
 
 local_config_file = None
+orig_config_file = args.original_config
 tmpl_dir = None
 
 for src in args.sources:
@@ -37,6 +43,12 @@ for src in args.sources:
 if local_config_file is None and os.path.isfile(LAST_LOCAL_CONFIG_FILE):
   local_config_file = open(LAST_LOCAL_CONFIG_FILE).read().strip()
 
+if orig_config_file is None:
+  if os.path.isfile(LAST_ORIG_CONFIG_FILE):
+    orig_config_file = open(LAST_ORIG_CONFIG_FILE).read().strip()
+  else:
+    orig_config_file = DEFAULT_ORIG_CONFIG
+
 if tmpl_dir is None and os.path.isfile(LAST_TMPL_DIR):
   tmpl_dir = open(LAST_TMPL_DIR).read().strip()
 
@@ -48,47 +60,57 @@ if not local_config_file or not os.path.isfile(local_config_file):
   print("No such config file: %r" % local_config_file)
   exit(1)
 
+if not os.path.isfile(orig_config_file):
+  print("No such config file: %r" % orig_config_file)
+  exit(1)
+
 local_config_file = os.path.realpath(local_config_file)
 tmpl_dir = os.path.realpath(tmpl_dir)
 net_dir = os.path.realpath(".")
 
 print(f'using config file: {local_config_file}')
+print(f'with original:     {orig_config_file}')
 print(f'on templates:      {tmpl_dir}')
 print(f'with NET_DIR:      {net_dir}')
 
 with open(LAST_LOCAL_CONFIG_FILE, 'w') as last_file:
   last_file.write(local_config_file)
+with open(LAST_ORIG_CONFIG_FILE, 'w') as last_file:
+  last_file.write(orig_config_file)
 with open(LAST_TMPL_DIR, 'w') as last_file:
   last_file.write(tmpl_dir)
 
-# read in variable values from config file
+# read in variable values from config files
 # NET_DIR is the folder where fill_config.py was started
 local_config = {"NET_DIR": net_dir}
 
-line_nr = 0
-for line in open(local_config_file):
-  line_nr += 1
-  line = line.strip('\n')
+for config_file in [orig_config_file, local_config_file]:
+  current_config_identifiers = ["NET_DIR"]
+  line_nr = 0
+  for line in open(config_file):
+    line_nr += 1
+    line = line.strip('\n')
 
-  if line.startswith('#'):
-    continue
+    if line.startswith('#'):
+      continue
 
-  if not '=' in line:
-    if line:
-      print("Error: %r line %d: %r" % (local_config_file, line_nr, line))
-      exit(1)
-    continue
+    if not '=' in line:
+      if line:
+        print("Error: %r line %d: %r" % (config_file, line_nr, line))
+        exit(1)
+      continue
 
-  split_pos = line.find('=')
-  name = line[:split_pos]
-  val = line[split_pos + 1:]
+    split_pos = line.find('=')
+    name = line[:split_pos]
+    val = line[split_pos + 1:]
 
-  if val.startswith('"') and val.endswith('"'):
-    val = val[1:-1]
+    if val.startswith('"') and val.endswith('"'):
+      val = val[1:-1]
 
-  if name in local_config:
-    print("Error: duplicate identifier in %r line %d: %r" % (local_config_file, line_nr, line))
-  local_config[name] = val
+    if name in current_config_identifiers:
+      print("Error: duplicate identifier in %r line %d: %r" % (config_file, line_nr, line))
+    local_config[name] = val
+    current_config_identifiers += [name]
 
 # replace variable names with above values recursively
 replace_re = re.compile('\$\{([A-Z_][A-Za-z0-9_]*)\}')
@@ -240,6 +262,7 @@ for tmpl_name in sorted(os.listdir(tmpl_dir)):
 
   if args.check_stale:
     check_stale(local_config_file, dst)
+    check_stale(orig_config_file, dst)
     check_stale(tmpl_src, dst)
 
   local_config['_fname'] = tmpl_name