Re: [Fab-user] How do I combine "local" with "remote" tasks in fabric 2?

[Brandon Whaley]

Have you tried instantiating a context with the config from Fabric's
connection?  I haven't mixed invoke tasks and fabric tasks in the same
module before, I'm surprised the same task decorator will work for
both using `inv` on the command line and `fab` as well.  If you have a
task that only does local work inside your fabfile module, I'd
recommend using conn.local instead of making it an invoke task.  If
you have an existing invoke task codebase, I would import that module
from my fabfile module and run tasks with a locally created context,
since you're not calling the task from the invoke cli.

```
tasks.py
====
from invoke.tasks import task

@task
def build(ctx):
   ctx.run('make artifact')

fabfile.py
====
from fabric.tasks import task
from invoke.context import Context
from tasks import build

@task(hosts=PROD)
def deploy(conn):
    ctx = Context(config=conn.config)
    build(ctx)
    conn.put('artifact', '/app')
```

On Tue, Apr 2, 2019 at 2:04 AM Michel Albert <address@hidden> wrote:
>
> I understand the differences. The only traceback I  got was the one I sent 
> earlier. This traceback is correct, only maybe a bit cryptic.
>
> So far, I managed to get some basic tasks ported to fabric2.
>
> However, this morning I ran into a new problem:
>
> I have a remote task (deploy) which depends on a local task (build) and I 
> want to be able to call the build step separately. But now I don't know how 
> to call "build" from the "deploy" task. The docs state to simply call the 
> function and forward the connection/context. But when calling from the 
> "deploy" task, I have a "Connection" instance, but I need a "Context" 
> instance to pass into the "build" task. Is there a way to get the Invoke 
> context from the Connection instance? Example:
>
> @task
> def build(ctx):
>    ctx.run('make artifact')
>
> @task(hosts=PROD)
> def deploy(conn):
>     build(?)  # <- what do I need to pass onto build? "conn" won't work
>     conn.put('artifact', '/app')
>
> On Mon, Apr 1, 2019 at 9:33 PM Brandon Whaley <address@hidden> wrote:
>>
>> There is no local attribute on invoke contexts, only on fabric
>> connections (which inherits from invoke contexts).  If this isn't what
>> you're trying to do, could you provide some code examples that give
>> you the traceback you're seeing?
>>
>> On Mon, Apr 1, 2019 at 1:07 PM Michel Albert <address@hidden> wrote:
>> >
>> > Ok. I think I will get it to work like that.
>> >
>> > But after fiddling around with it I found out that the type of the first 
>> > argument depends on whether a "hosts" argument was passed into the task 
>> > decorator or not. This was quite confusing. And the error is a bit 
>> > cryptic. When calling "local" on an invoke context, the following 
>> > AttributeError is thrown:
>> >
>> > Traceback (most recent call last):
>> >   File "/usr/lib/python3.7/site-packages/invoke/config.py", line 113, in 
>> > __getattr__
>> >     return self._get(key)
>> >   File "/usr/lib/python3.7/site-packages/invoke/config.py", line 178, in 
>> > _get
>> >     value = self._config[key]
>> >   File "/usr/lib/python3.7/site-packages/invoke/config.py", line 169, in 
>> > __getitem__
>> >     return self._get(key)
>> >   File "/usr/lib/python3.7/site-packages/invoke/config.py", line 178, in 
>> > _get
>> >     value = self._config[key]
>> > KeyError: 'local'
>> >
>> > During handling of the above exception, another exception occurred:
>> >
>> > Traceback (most recent call last):
>> >   File "/home/exhuma/.local/bin/fab", line 10, in <module>
>> >     sys.exit(program.run())
>> >   File "/usr/lib/python3.7/site-packages/invoke/program.py", line 363, in 
>> > run
>> >     self.execute()
>> >   File "/usr/lib/python3.7/site-packages/invoke/program.py", line 532, in 
>> > execute
>> >     executor.execute(*self.tasks)
>> >   File "/usr/lib/python3.7/site-packages/invoke/executor.py", line 129, in 
>> > execute
>> >     result = call.task(*args, **call.kwargs)
>> >   File "/usr/lib/python3.7/site-packages/invoke/tasks.py", line 128, in 
>> > __call__
>> >     result = self.body(*args, **kwargs)
>> >   File "/home/exhuma/tmp/fabfile.py", line 8, in get_version
>> >     version = ctx.local('python setup.py --version').strip()
>> >   File "/usr/lib/python3.7/site-packages/invoke/config.py", line 125, in 
>> > __getattr__
>> >     raise AttributeError(err)
>> > AttributeError: No attribute or config key found for 'local'
>> >
>> > Valid keys: ['connect_kwargs', 'forward_agent', 'gateway', 
>> > 'inline_ssh_env', 'load_ssh_configs', 'port', 'run', 'runners', 
>> > 'ssh_config_path', 'sudo', 'tasks', 'timeouts', 'user']
>> >
>> > Valid real attributes: ['cd', 'clear', 'config', 'cwd', 'from_data', 
>> > 'pop', 'popitem', 'prefix', 'run', 'setdefault', 'sudo', 'update']
>> >
>> >
>> > On Mon, Apr 1, 2019 at 5:37 PM Brandon Whaley <address@hidden> wrote:
>> >>
>> >> Hi Mich,
>> >>
>> >> The connection object (you're using ctx in your examples) has a .local
>> >> method that is just a pass-through to invoke.run.  It's documented on
>> >> the connection object's page:
>> >> http://docs.fabfile.org/en/2.4/api/connection.html?highlight=local#fabric.connection.Connection.local
>> >>
>> >> On Mon, Apr 1, 2019 at 5:55 AM Michel Albert <address@hidden> wrote:
>> >> >
>> >> > Hi,
>> >> >
>> >> >
>> >> > Consider the following fabric-1 task. For illustration I kept it really 
>> >> > short:
>> >> >
>> >> > @fab.task
>> >> > def sample():
>> >> >     version = fab.local('python setup.py --version')
>> >> >     fab.run('mkdir -p /snapshots/%s' % version.strip())
>> >> >
>> >> > This task needs to run a local and remote command. I am now trying to 
>> >> > port this to fabric-2, and I can't figure out how I can implement this. 
>> >> > If I define the "hosts" variable in the task, then the first line will 
>> >> > be executed on the remote host as well, which I don't want. A naive 
>> >> > aproach which won't work:
>> >> >
>> >> > @task(hosts=PROD)
>> >> > def sample(ctx):
>> >> >     version = ctx.run('python setup.py --version').strip()   # <- this 
>> >> > won't work
>> >> >     ctx.run('mkdir -p /snapshots/%s' % version)
>> >> >
>> >> > At first I thought I would split the task into two, one for just local 
>> >> > commands and one for remote tasks, but then I am forced to pass in the 
>> >> > context, which will in turn cause it again to be run remotely:
>> >> >
>> >> > @task
>> >> > def get_version(ctx):
>> >> >     version = ctx.run('python setup.py --version').strip()
>> >> >     return version
>> >> >
>> >> > @task(hosts=PROD)
>> >> > def sample(ctx):
>> >> >     version = get_version(ctx)  # <- this won't work
>> >> >     ctx.run('mkdir -p /snapshots/%s' % version)
>> >> >
>> >> > How can I accomplish something like this? And where is it noted in the 
>> >> > docs? In the current example on the "Upgrading from 1.x" page does not 
>> >> > have a single task mixing local with remote commands in any way.
>> >> >
>> >> >
>> >> > Regards,
>> >> >
>> >> >
>> >> > Mich
>> >> >
>> >> > _______________________________________________
>> >> > Fab-user mailing list
>> >> > address@hidden
>> >> > https://lists.nongnu.org/mailman/listinfo/fab-user