Setting fabric hosts list from an external hosts file

Question

I need to get fabric to set its hosts list by opening and reading a file to get the hosts. Setting it this way allows me to have a huge list of hosts without needing to edit my fabfile for this data each time. I tried this: ``` def set_hosts(): env.hosts = [line.split(',') for line in open("host_file")] def uname(): run("uname -a") ``` and ``` def set_hosts(): env.hosts = open('hosts_file', 'r').readlines def uname(): run("uname -a") ``` I get the following error each time I try to use the function set_hosts: ``` fab set_hosts uname Traceback (most recent call last): File "/usr/local/lib/python2.7/dist-packages/fabric/main.py", line 712, in main *args, **kwargs File "/usr/local/lib/python2.7/dist-packages/fabric/tasks.py", line 264, in execute my_env['all_hosts'] = task.get_hosts(hosts, roles, exclude_hosts, state.env) File "/usr/local/lib/python2.7/dist-packages/fabric/tasks.py", line 74, in get_hosts return merge(*env_vars) File "/usr/local/lib/python2.7/dist-packages/fabric/task_ut…

Accepted Answer

The problem you're hitting here is that you're setting env.hosts to a function object, not a list or iterable. You need the parens after readlines, to actually call it:

```
def set_hosts():
    env.hosts = open('hosts_file', 'r').readlines()
```

Setting fabric hosts list from an external hosts file

Solution

Problem