Support optional BOTO specification with --no_auth.

download_from_google_storage.py

Index: download_from_google_storage.py
diff --git a/download_from_google_storage.py b/download_from_google_storage.py
index 09be339d452bbaefbafd2055ecfe1458aa607e2d..d56ad1d25e530e1d88b224189701a84023876843 100755
--- a/download_from_google_storage.py
+++ b/download_from_google_storage.py
@@ -384,7 +384,15 @@ def main(args):
 
   # Set the boto file to /dev/null if we don't need auth.
   if options.no_auth:
-    options.boto = os.devnull
+    if (os.environ.get('BOTO_CONFIG') and not
+        os.environ.get('NO_AUTH_BOTO_CONFIG')):

[hinoka, 2015/01/14 18:50:15]

Lets only trigger this if proxy settings are detected.  Otherwise this message
will show up literally everywhere.

[Michael Moss, 2015/01/14 20:04:05]

Everyone exports BOTO_CONFIG? The case I'm concerned about it somebody exporting
BOTO_CONFIG, expecting proxying to work, and wonder why it's not. This should
make it pretty clear what's going on.

+      print >> sys.stderr, ('NOTICE: You have BOTO_CONFIG set in your '
+                            'environment, but the "--no_auth" flag prevents '
+                            'it from being used.\n'

[hinoka, 2015/01/14 18:50:15]

Split this into two print statements. '\n' isn't technically windows friendly.

[Michael Moss, 2015/01/14 21:05:44]

Done.

+                            'If you need boto configs even when using '
+                            '--no_auth (e.g. proxy settings), export your '
+                            'BOTO_CONFIG as NO_AUTH_BOTO_CONFIG instead.')

[hinoka, 2015/01/14 18:50:15]

s/instead/also/

[Michael Moss, 2015/01/14 21:05:44]

Done.

+    options.boto = os.environ.get('NO_AUTH_BOTO_CONFIG', os.devnull)
 
   # Make sure gsutil exists where we expect it to.
   if os.path.exists(GSUTIL_DEFAULT_PATH):