Molecule: Add error checking to extra hosts links keys

[TomaszKlosinski]

Issue Type

• Bug report

Molecule and Ansible details

$ ansible --version && molecule --version
ansible 2.7.8
  config file = None
  configured module search path = [u'/Users/tomasz/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /Users/tomasz/Library/Python/2.7/lib/python/site-packages/ansible
  executable location = /Users/tomasz/Library/Python/2.7/bin/ansible
  python version = 2.7.15 (default, Feb 12 2019, 12:27:02) [GCC 4.2.1 Compatible Apple LLVM 10.0.0 (clang-1000.11.45.5)]
molecule, version 2.19.0

Molecule installation method:

• pip

Ansible installation method:

• pip

Detail any linters or test runners used:

• No linters and tests, problem occurs when creating $MOLECULE_EPHEMERAL_DIRECTORY directory.

Desired Behavior

I'm trying to configure symlinks to inventory file (hosts), group_vars and host_vars of my prod environment:

---

dependency:
  name: galaxy
driver:
  name: docker
lint:
  name: yamllint
platforms:
  - name: instance1
    image: ubuntu:18.04
    groups:
      - haproxy-group
  - name: instance2
    image: ubuntu:18.04
    groups:
      - haproxy-group
provisioner:
  name: ansible
  log: true
  inventory:
    links:
      hosts: ../../../../env/live/inventory/hosts
      group_vars: ../../../../env/live/inventory/group_vars
      host_vars: ../../../../env/live/inventory/host_vars
  env:
    ANSIBLE_ROLES_PATH: ../../../../roles/
  playbooks:
    converge: ../../haproxy.yml
  lint:
    name: ansible-lint
scenario:
  name: default
verifier:
  name: testinfra
  lint:
    name: flake8

Actual Behaviour

$ molecule --debug converge
--> Validating schema /Users/tomasz/ansible-playbooks/haproxy/molecule/default/molecule.yml.
Validation completed successfully.
--> Test matrix

└── default
    ├── dependency
    ├── create
    ├── prepare
    └── converge

--> Inventory /Users/tomasz/ansible-playbooks/haproxy/molecule/default/../../../../env/live/inventory/group_vars linked to /var/folders/1r/bt9yc5vd7fd0k8sqvw73xs900000gn/T/molecule/haproxy/default/group_vars
--> Inventory /Users/tomasz/ansible-playbooks/haproxy/molecule/default/../../../../env/live/inventory/hosts linked to /var/folders/1r/bt9yc5vd7fd0k8sqvw73xs900000gn/T/molecule/haproxy/default/hosts
Traceback (most recent call last):
  File "/Users/tomasz/Library/Python/2.7/bin/molecule", line 10, in <module>
    sys.exit(main())
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/click/core.py", line 1066, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/molecule/command/converge.py", line 112, in converge
    base.execute_subcommand(scenario.config, action)
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/molecule/command/base.py", line 100, in execute_subcommand
    return command(config).execute()
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/molecule/command/base.py", line 51, in __init__
    self._setup()
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/molecule/command/base.py", line 93, in _setup
    self._config.provisioner.manage_inventory()
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/molecule/provisioner/ansible.py", line 633, in manage_inventory
    self._link_or_update_vars()
  File "/Users/tomasz/Library/Python/2.7/lib/python/site-packages/molecule/provisioner/ansible.py", line 718, in _link_or_update_vars
    os.symlink(source, target)
OSError: [Errno 17] File exists
````

However, the symlink is actually created in $MOLECULE_EPHEMERAL_DIRECTORY:

$ ll $MOLECULE_EPHEMERAL_DIRECTORY
total 32
-rw-r--r-- 1 tomasz staff 151B Mar 18 11:00 Dockerfile_ubuntu_18_04
-rw-r--r-- 1 tomasz staff 239B Mar 18 11:03 ansible.cfg
-rw-r--r-- 1 tomasz staff 713B Mar 18 11:03 ansible_inventory.yml
lrwxr-xr-x 1 tomasz staff 117B Mar 18 11:03 group_vars -> /Users/tomasz/ansible-playbooks/haproxy/molecule/default/../../../../env/live/inventory/group_vars
lrwxr-xr-x 1 tomasz staff 112B Mar 18 11:02 hosts -> /Users/tomasz/ansible-playbooks/haproxy/molecule/default/../../../../env/live/inventory/hosts
-rw-r--r-- 1 tomasz staff 85B Mar 18 11:03 state.yml

Everything works fine when I comment out:

hosts: ../../../../env/live/inventory/hosts
```

[decentral1se]

Thanks for the report @TomaszKlosinski!

Looks like something related to the recent https://github.com/ansible/molecule/pull/1774.

cc @beenje

[TomaszKlosinski]

One more interesting discovery - the same error happens when I try to create a random symlink:

provisioner:
  name: ansible
  inventory:
    links:
      whatever: ../../../../env/live/inventory/whatever

But the link gets created:

$ ll $MOLECULE_EPHEMERAL_DIRECTORY | grep whatever
lrwxr-xr-x  1 tomasz  staff   115B Mar 18 11:38 whatever -> /Users/tomasz/ansible-playbooks/haproxy/molecule/default/../../../../env/live/inventory/whatever

[beenje]

Just by reading this, what is strange is that the links should be created under $MOLECULE_EPHEMERAL_DIRECTORY/inventory not directly under $MOLECULE_EPHEMERAL_DIRECTORY.
I'll try to look more into it.

[TomaszKlosinski]

Do I understand correctly that the fix is merged into 2.20? When will you release that version and make it available via pip?

[decentral1se]

There's no fix yet AFAIK @TomaszKlosinski and the release date for v2.20 is still not clear.

[beenje]

I didn't react but using hosts in links is not supported in molecule 2.19.0.
It was added in 2.20 which isn't released yet.

One thing that could be done is checking the keys passed to links.
There is no check today. So as you noticed, you can pass whatever. This should raise an error.

[TomaszKlosinski]

Thanks for the information. I'll test this tomorrow with 2.20 or devel.

[TomaszKlosinski]

I've upgraded to 2.20 and it seems to work fine. Thanks for the help.

[decentral1se]

That's great :+1:

Leaving open to track for https://github.com/ansible/molecule/issues/1845#issuecomment-474604047.