reload_modules: True does not reload module dependencies

[klyr]

Hi,

I would like to use the swiftexecution module to install an application.
For the swift execution module to be enabled, one need to install the python-swiftclient library first.

$ salt --versions-report
           Salt: 2015.5.2-120-g1650233
         Python: 2.7.6 (default, Mar 22 2014, 22:59:56)
         Jinja2: 2.7.2
       M2Crypto: 0.21.1
 msgpack-python: 0.4.6
   msgpack-pure: Not Installed
       pycrypto: 2.6.1
        libnacl: Not Installed
         PyYAML: 3.10
          ioflo: Not Installed
          PyZMQ: 14.0.1
           RAET: Not Installed
            ZMQ: 4.0.4
           Mako: Not Installed
        Tornado: Not Installed

Here is a simple SLS file:

python-swiftclient:
  pip.installed:
    - reload_modules: True

python-keystoneclient:
  pip.installed:
    - reload_modules: True

python-dev:
  pkg.installed

download_application:
  module.run:
    - name: swift.get
    - cont: test_container
    - path: test_app
    - local_file: /tmp/test_app
    - require:
      - pip: python-keystoneclient
      - pip: python-swiftclient

The execution of this SLS file fails at the download_application step because it says that the swift module is not present:

     Changes:
----------
          ID: download_application
    Function: module.run
        Name: swift.get
      Result: False
     Comment: Module function swift.get is not available
     Started: 12:42:28.767301
    Duration: 200.984 ms
     Changes:

In order to make it work, I need to restart the minion to be aware of the new python-swiftclient library being installed, and re-run the SLS file.

By looking at the source code, we can see that the python reload() function is called for the modules/swift.py module, so the module is effectively reloaded.

BUT, its dependencies are not (this is not the behaviour of the reload() function)

We can see at https://github.com/saltstack/salt/blob/develop/salt/modules/swift.py#L46 that swift.py imports salt.utils.openstack.swift that is "evaluated" once, on first import (re-importing a library does not mean the library is re-evaluated)

So at https://github.com/saltstack/salt/blob/develop/salt/utils/openstack/swift.py#L22 the following code is only executed once and the variable HAS_SWIFT is still set to False even after the swift.py module is reloaded because reload() does not reload python dependencies.

# Import Swift client libs
HAS_SWIFT = False
try:
    from swiftclient import client

    HAS_SWIFT = True
except ImportError:
    pass

Other modules like docker.io are not affected by this problem because they directly import third-party libraries and upon reloading, they retry to import these libraries. So installing docker-py with reload_modules: True enables the docker.io execution module without restarting the minion.

Adding a reload(suos) call in the virtual() function fixes the problem but this is not a clean solution.

Questions:

• Do I install the third party library the right way ?
• Should I expect that the installation of a third party library is taken into account without restarting the minion ?

Cheers.

[arroyoc]

@klyr Thanks for your report.

[mitar]

We have the same problem with pip:

python-pip:
  pkg.installed:
    - reload_modules: True

So because reload does not work, other states which depend on pip fail with:

State 'pip.installed' found in SLS is unavailable

cc @kostko

[ltsampros]

Is there any update on this? Edit: it seems to be affecting lots of people that are trying to workaround the recent pip issues (#33163).