molecule_vagrant/modules/vagrant.py: Improve error handling (#80)

- Make sure that up() is exiting with either exit_json() or fail_json()
- Catch errors for calls to vagrant.conf() and vagrant.status()

- Now that the functions up/destroy/halt of the VagrantClient class
should all be exiting with proper fail/exit_json, but in the case of
the last line of main() is still reached, change the code to use
VagrantClient result to avoid the following exception:

AttributeError: 'AnsibleModule' object has no attribute 'result'

Signed-off-by: Arnaud Patard <apatard@hupstream.com>

molecule_vagrant/modules/vagrant.py

@@ -448,17 +448,17 @@ def up(self):
  # passes the actual error as a no-argument ContextManager.
  pass
 
-  # NOTE(retr0h): Ansible wants only one module return `fail_json`
-  # or `exit_json`.
-  if not self._has_error:
-  self._module.exit_json(
-  changed=changed, log=self._get_stdout_log(), **self._conf()
-  )
- else:
-  msg = "ERROR: See log file '{}'".format(self._get_stderr_log())
-  with io.open(self._get_stderr_log(), "r", encoding="utf-8") as f:
-  self.result["stderr"] = f.read()
-  self._module.fail_json(msg=msg, **self.result)
+ # NOTE(retr0h): Ansible wants only one module return `fail_json`
+ # or `exit_json`.
+ if not self._has_error:
+ self._module.exit_json(
+ changed=changed, log=self._get_stdout_log(), **self._conf()
+ )
+
+ msg = "Failed to start the VM: See log file '{}'".format(self._get_stderr_log())
+ with io.open(self._get_stderr_log(), "r", encoding="utf-8") as f:
+ self.result["stderr"] = f.read()
+ self._module.fail_json(msg=msg, **self.result)
 
  def destroy(self):
  changed = False
@@ -481,18 +481,29 @@ def halt(self):
  def _conf(self):
  instance_name = self._module.params["instance_name"]
 
- return self._vagrant.conf(vm_name=instance_name)
+ try:
+ return self._vagrant.conf(vm_name=instance_name)
+ except Exception:
+ msg = "Failed to get vagrant config for {}: See log file '{}'".format(
+ instance_name, self._get_stderr_log()
+ )
+ with io.open(self._get_stderr_log(), "r", encoding="utf-8") as f:
+ self.result["stderr"] = f.read()
+ self._module.fail_json(msg=msg, **self.result)
 
  def _status(self):
  instance_name = self._module.params["instance_name"]
  try:
  s = self._vagrant.status(vm_name=instance_name)[0]
 
  return {"name": s.name, "state": s.state, "provider": s.provider}
- except AttributeError:
- pass
- except subprocess.CalledProcessError:
- pass
+ except Exception:
+ msg = "Failed to get status for {}: See log file '{}'".format(
+ instance_name, self._get_stderr_log()
+ )
+ with io.open(self._get_stderr_log(), "r", encoding="utf-8") as f:
+ self.result["stderr"] = f.read()
+ self._module.fail_json(msg=msg, **self.result)
 
  def _created(self):
  status = self._status()
@@ -632,7 +643,7 @@ def main():
  if module.params["state"] == "halt":
  v.halt()
 
- module.exit_json(**module.result)
+ module.fail_json(msg="Unknown error", **v.result)
 
 
 if __name__ == "__main__":