infra/go: Adding setup instructions and quick setup script.

go/bootstrap.py

 #!/usr/bin/env python
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Prepares a local hermetic Go installation.
 
 - Downloads and unpacks the Go toolset in ../../golang.
 - Downloads and installs Glide (used by deps.py).
 - Fetches code dependencies via deps.py.
@@ skipping 412 matching lines @@
 
   # APPENGINE_DEV_APPSERVER is used by "appengine/aetest" package. If it's
   # missing, aetest will scan PATH looking for dev_appserver.py, possibly
   # finding it in some other place.
   if go_appengine_path:
     env['APPENGINE_DEV_APPSERVER'] = os.path.join(
         go_appengine_path, 'dev_appserver.py')
   else:
     env.pop('APPENGINE_DEV_APPSERVER', None)
 
+  # Add a tag to the prompt
+  prompt = env.get('PS1')
+  if prompt:
+    if not prompt.startswith('[cr-infra-go-area] '):

[Vadim Sh., 2016/06/18 16:12:09]

nit: '[cr-infra-go-area]' not in prompt

(I can imagine there can be other PS1 modifications on top of this one).

[mithro, 2016/06/20 14:19:26]

Done.

+      env['PS1'] = '[cr-infra-go-area] ' + prompt

[Vadim Sh., 2016/06/18 16:12:09]

good enough, though I'm very tempted to bikeshed and ask to rename it to just
[go env] to save space... It is okay?)

[mithro, 2016/06/20 14:19:26]

I'd like the prompt to match the script you run...

We could make it a command line flag?

[Eric Burnett, 2016/06/20 14:32:09]

Command line flag sounds hard - users don't generally run this program directly
(it's run via env.py, which is run via quickstart), so you'd have to pass it
through all of them, no?

Also, if a user hasn't run the quickstart script, does 'cr-infra-go-area' make
any sense? I think this is the first place they'd see that, so it wouldn't be
super meaningful for the prompt in the first place. So I'd vote for something
small and clear in context -- [go env] or [cr go env].

(I'm also somewhat against prompt changes as a whole, speaking as someone with a
complicated prompt already that would look stupid with this prefixed onto it.
But I'm the kind of person who will manually export the right variables printed
by env.py instead of going through the scripts each time, so my opinion may not
matter here :) ).

[mithro, 2016/06/21 06:55:05]

If I make it a command line argument I can set it to something shorter by
default and then have the quickstart script override it to the longer name....

[M-A Ruel, 2016/06/21 12:21:44]

My bikeshed color would be '\033[33;1mcit\033[0m ' + prompt but I don't mind
much.

[mithro, 2016/06/22 04:39:20]

Adding a command line flag turned out to be a bigger change than I wanted to go
with, so I used the INFRA_PROMPT_TAG environment variable.

The default value is the short "[cr go] ". If you want nothing, "export
INFRA_PROMPT_TAG=''"

The quicksetup script uses "[cr-infra-go-env] " to match the enter script's
name.

+
   return env
 
 
 def get_go_exe(toolset_root):
   """Returns path to go executable."""
   return os.path.join(toolset_root, 'go', 'bin', 'go' + EXE_SFX)
 
 
 def bootstrap(go_paths, logging_level, toolset=None):
   """Installs all dependencies in default locations.
@@ skipping 126 matching lines @@
         'Linux')
 
   bootstrap([WORKSPACE], logging.DEBUG, toolset=opts.toolset)
   if opts.build_cross:
     build_cross_toolset(opts.toolset)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))