Merge lp:~gz/juju-deployer/polite_juju_install_check into lp:juju-deployer

[Martin Packman]

Display a nice error if juju-deployer is run without juju installed.

A new juju-deployer user I was introducing to the tool got a python traceback on first attempt. This branch catches the executable not found exception when looking up the juju version and gives a hint to install it.

As a drive-by, also ignore the build directory created by setup.py script.

[Kapil Thangavelu (hazmat)]

Thanks looks good

review: Approve

=== modified file '.bzrignore'
--- .bzrignore	2013-11-12 14:09:56 +0000
+++ .bzrignore	2013-12-18 10:08:28 +0000
@@ -2,6 +2,7 @@
 .emacs.desktop.lock
 *.egg
 _build
+build
 deployer.sublime-project
 deployer.sublime-workspace
 dist/

=== modified file 'deployer/cli.py'
--- deployer/cli.py	2013-11-21 03:19:56 +0000
+++ deployer/cli.py	2013-12-18 10:08:28 +0000
@@ -8,6 +8,7 @@
 
 
 import argparse
+import errno
 import logging
 import os
 import sys
@@ -138,7 +139,13 @@
     log = logging.getLogger("deployer.cli")
     start_time = time.time()
 
-    env = select_runtime(options.juju_env, options)
+    try:
+        env = select_runtime(options.juju_env, options)
+    except OSError as e:
+        if e.errno != errno.ENOENT:
+            raise
+        log.error("No juju binary found, have you installed juju?")
+        sys.exit(1)
     log.debug('Using runtime %s', env.__class__.__name__)
 
     config = ConfigStack(options.configs or [])