From 7c08b582ded9b74cf8ec62d8996b7f8d80c83402 Mon Sep 17 00:00:00 2001
From: Mehdi Abaakouk <mehdi.abaakouk@enovance.com>
Date: Mon, 8 Sep 2014 07:04:33 +0200
Subject: [PATCH] Checks that docker is installed

The current error when docker is missing is not very helpful:

 ERROR: Operation failed, aborting dox.

The debug one doesn't help more, this change start 'docker version'
command earlier to have a clear error message.

Change-Id: I1e6ac247b0a619915600f604d5f316d5f053e8c1
---
 dox/cmd.py    |  3 +++
 dox/runner.py | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/dox/cmd.py b/dox/cmd.py
index cadde36..3aed150 100644
--- a/dox/cmd.py
+++ b/dox/cmd.py
@@ -15,6 +15,7 @@
 
 import argparse
 import logging
+import sys
 
 import dox.commands
 import dox.config.cmdline
@@ -75,6 +76,8 @@ def main():
 
 
 def run_dox(args):
+    if not dox.runner.Runner(args).is_docker_installed():
+        sys.exit(1)
 
     # Get Image
     image = args.image
diff --git a/dox/runner.py b/dox/runner.py
index b26a268..2264648 100644
--- a/dox/runner.py
+++ b/dox/runner.py
@@ -37,6 +37,18 @@ class Runner(object):
         self.base_image_name = 'dox_%s_base' % self.project
         self.test_image_name = 'dox_%s_test' % self.project
 
+    def is_docker_installed(self):
+        try:
+            self._docker_cmd("version")
+        except OSError as e:
+            msg = 'docker does not seem installed'
+            if e.errno == 2 and not self.args.debug:
+                logger.error(msg)
+            else:
+                logger.exception(msg)
+            return False
+        return True
+
     def _docker_build(self, image, image_dir='.'):
         logger.info('Building image %s' % image)
         self._docker_cmd('build', '-t', image, image_dir)