when does ansible-playbook write to stdout?

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1

Hey guys,

Since using Ansible >= 1.3.0 I’ve noticed that when provisioning a Vagrant VM the output of ansible-playbook is not shown until it has finished (whether it be an error or a successful provision).

I’ve had a look in the Vagrant source code and in https://github.com/mitchellh/vagrant/blob/master/plugins/provisioners/ansible/provisioner.rb the following can be seen:


result = Vagrant::Util::Subprocess.execute(*command) do |type, data|
  if type == :stdout || type == :stderr
    @machine.env.ui.info(data, :new_line => false, :prefix => false)
  end
end

This looks to me like it’s just redirecting stdout/err from ansible-playbook to the host machine’s terminal. I have raised a ticket with Vagrant (https://github.com/mitchellh/vagrant/issues/2194).

If I run ansible-playbook by hand in the terminal I get ‘realtime’ feedback of task execution rather than solely at the end of the run, e.g.

ansible-playbook
~/Development/playbook.yml
-i ~/Development/inventory
-u vagrant
–private-key=~/.vagrant.d/insecure_private_key

My question is, when does Ansible write to stdout? Did this change at all between 1.2.x → 1.3?

Many thanks :slight_smile:

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2

In order to replicate I have created a simple node.js script:

#!/usr/bin/env node
var spawn = require(‘child_process’).spawn;
var args = [
‘/Users/jake/Development/playbook.yml’,
‘-i’, ‘/Users/jake/Development/inventory’,
‘-u’, ‘vagrant’,
‘–private-key’, ‘/Users/jake/.vagrant.d/insecure_private_key’
];

var proc = spawn(‘ansible-playbook’, args, {
cwd: process.cwd()
});

proc.stdout.on(‘data’, function(data) {
console.log(data.toString());
});

proc.stderr.on(‘data’, function(data) {
console.error(data.toString());
});

3

Yes, ansible obviously writes to stdout.

I’m pretty sure you have a problem with vagrant here, and this should be reported on the vagrant bug tracker.

4

Thanks for the reply.

I agree it looks like a Vagrant issue. It does seem strange that if I use Ansible 1.2.x with the same version of Vagrant (1.3.3) I get the output on a task-by-task basis.

With the node.js example would you expect that just to trigger the ‘data’ event of the stdout at the end or after each task?

5

Yes I noticed the same after upgrade to 1.3 Ansible.
export PYTHONUNBUFFERED=1
This fixes the issue if ansible execution is wrapped with some other process

6

So weird that I’ve never heard of that environment variable until now.

7

Thanks Dmitry, that solved the problem :slight_smile:

8

Have submitted a PR to Vagrant for this:

https://github.com/mitchellh/vagrant/pull/2275

Thanks all for your help :slight_smile:

9

Thanks very much!

We have lots of vagrant users so this will definitely continue to keep them happy.

10

Thanks for this fix! I ran into this issue when running ansible-playbook as part of a shell provisioning script in Vagrant. In other words, Vagrant is just running a shell script, and the shell script is running “sudo ansible-playbook” in local mode. However, I just wanted to point out that in this case, the following doesn’t work as I expected:

export PYTHONUNBUFFERED=1
sudo ansible-playbook /vagrant/provisioning/playbook.yml --connection=local -i “[database]127.0.0.1,”

Of course, I’m a Linux noobie, and it took me a while to realize I needed to do this instead:
sudo PYTHONUNBUFFERED=1 ansible-playbook …

Or this:
sudo python -u which ansible-playbook …

The “PYTHONUNBUFFERED” env variable didn’t survive the call to sudo, which makes sense in hindsight. Anyway, in case anyone else is running into this instead of using Vagrant’s built-in Ansible provisioner, I wanted to post the solution here since this thread is a likely place to stumble.

Taylor

11

Did this ever get addressed in Vagrant?

12

Yep, it was resolved in Vagrant 1.3.4.