Hi,
I think your example would work if your task is called this way (link
<http://docs.fabfile.org/en/1.10/usage/execution.html#globally-via-env>):
fab PickHosts DoTheUpdates
A faster approach that also avoids the concatention of tasks, could be
this, if you don't mind to have the host list hardcoded:
# Fabric modules
from fabric.api import env,run,local,hosts, task, settings, hide, parallel
@parallel
def PickHosts():
host_list = ['host1', 'host2']
hosts_alive = []
with (settings(hide('everything'), warn_only = True)):
for host in host_list:
PickAttempt = local('ping -c 1 {host}'.format(host = host), capture = True)
if PickAttempt.succeeded:
hosts_alive.append(host)
return hosts_alive
@task
@hosts(PickHosts())
def DoTheUpdates():
run('echo')
Be aware that PickHost will be executed every time you run fab, as it
executes PickHost() when importing. Anyway, there are workarounds; append
this:
if __name__ == '__main__':
def PickHosts():
return []
If you prefer to pass the host/roles list via command-line, maybe the best
approach is to use execute
<http://docs.fabfile.org/en/1.10/api/core/tasks.html?highlight=execute#fabric.tasks.execute>,
creating the host list prior to the execute() call. I haven't tested,
though.
Regards
2015-09-17 1:46 GMT+02:00 Paul Hoffman <[email protected]>:
> --hide hides *all* warnings, not just host-unreachable warnings, correct?
> That is certainly not what I want.
>
> To recap: I want to do an initial silent check for the host list to see
> which are not up, and then only run the main procedures on the hosts known
> to be up. Is this possible with Fabric?
>
> On Wed, Sep 16, 2015 at 9:33 AM, Carlos García <
> [email protected]> wrote:
>
>> Hi Paul,
>>
>> if you want to hide this kind of output, you can use --hide
>>
>> fab DoTheUpdates --skip-bad-hosts --hide=warnings -H <comma-separated
>> list of hosts>
>>
>> Check this out if you want to hide other kinds of output messages [
>> http://docs.fabfile.org/en/1.10/usage/output_controls.html]
>>
>>
>> Regards
>>
>>
>>
>> 2015-09-16 18:21 GMT+02:00 Paul Hoffman <[email protected]>:
>>
>>> --skip-bad-hosts (or env.skip_bad_hosts) doesn't seem to work for this.
>>> That is, using either (or both), DoTheUpdates says:
>>>
>>> Warning: Timed out trying to connect to host2 (tried 1 time)
>>> Underlying exception:
>>> timed out
>>>
>>> That doesn't seem like "skipping". What else do I need to do here to
>>> make bad hosts skipped silently?
>>>
>>> On Wed, Sep 16, 2015 at 12:52 AM, Carlos García <
>>> [email protected]> wrote:
>>>
>>>> I think --skip-bad-hosts would do the work.
>>>>
>>>> Try:
>>>>
>>>> fab DoTheUpdates --skip-bad-hosts -H <comma-separated list of hosts>
>>>>
>>>> Regards
>>>>
>>>> 2015-09-16 1:52 GMT+02:00 Paul Hoffman <[email protected]>:
>>>>
>>>>> Greetings. I want a script to do an update to all of the hosts that
>>>>> are alive, but not spend time on ones that aren't. I tried the following
>>>>> as
>>>>> a way of filling env.hosts:
>>>>>
>>>>> @hosts("me@host1", "me@host2")
>>>>> def PickHosts():
>>>>> PickAttempt = run("echo")
>>>>> if PickAttempt.succeeded:
>>>>> (env.hosts).append(env.host_string)
>>>>> print("Adding {}".format(env.host_string))
>>>>> PickHosts()
>>>>>
>>>>> def DoTheUpdates(): ...
>>>>>
>>>>> However, running this with a command line of "fab DoTheUpdates",
>>>>> prompts:
>>>>> No hosts found. Please specify (single) host string for connection:
>>>>>
>>>>> How can I get the above code to work? Or if this is too much of a
>>>>> kludge, what is the proper way to have DoTheUpdates try a bunch of hosts
>>>>> but gracefully stop each time it can't log into one?
>>>>>
>>>>> --Paul Hoffman
>>>>>
>>>>> _______________________________________________
>>>>> Fab-user mailing list
>>>>> [email protected]
>>>>> https://lists.nongnu.org/mailman/listinfo/fab-user
>>>>>
>>>>>
>>>>
>>>>
>>
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