add connection by URL endpoint when region not specified

[eric-belhomme]

SUMMARY

The ec2_vol module connects to AWS endpoint using legacy boto Python library (instead of newer boto3 Python lib) and require to specify the AWS region because it uses boto.ec2.connect_to_region() method

Altrough this is not an issue when operation with official Amazon Web Services this will irremebiably fail with alternate cloud providers that propose an AWS-compliant API, like Outscale
In such case, we require to specify an API endpoint instead of an AWS region, and use boto.connect_ec2_endpoint() in place of boto.ec2.connect_to_region()

This PR adds an alternate EC2 connection method when region parameter is not set:

    if region:
        try:
            ec2 = connect_to_aws(boto.ec2, region, **aws_connect_params)
        except (boto.exception.NoAuthHandlerFound, AnsibleAWSError) as e:
            module.fail_json(msg=str(e))
    elif ec2_url:
        try:
            ec2 = boto.connect_ec2_endpoint(ec2_url, **aws_connect_params)
        except (boto.exception.NoAuthHandlerFound, AnsibleAWSError, boto.provider.ProfileNotFoundError) as e:
            module.fail_json(msg=str(e))
    else:
        module.fail_json(msg="Either region or ec2_url must be specified")

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

ec2_vol

ADDITIONAL INFORMATION

Without this patch, ec2_vol will fail with an erroneous error message:

 ansible localhost -vv -m ec2_vol -a "ec2_url=https://fcu.eu-west-2.outscale.com region=eu-west-2 volume_type=gp2 volume_size=5 zone=eu-west-2a"
ansible 2.9.6
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/rico/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /opt/ansible-lint/lib/python3.7/site-packages/ansible
  executable location = /opt/ansible-lint/bin/ansible
  python version = 3.7.3 (default, Dec 20 2019, 18:57:59) [GCC 8.3.0]
Using /etc/ansible/ansible.cfg as config file
META: ran handlers
localhost | FAILED! => {
    "changed": false,
    "msg": "AuthFailure: AWS was not able to validate the provided access credentials"
}

With the patch, things got better:

$ ansible localhost -vv -m ec2_vol -a "ec2_url=https://fcu.eu-west-2.outscale.com volume_type=gp2 volume_size=5 zone=eu-west-2a"
Wed 01 Apr 2020 10:31:36 PM CEST
ansible 2.9.6
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/rico/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /opt/ansible-lint/lib/python3.7/site-packages/ansible
  executable location = /opt/ansible-lint/bin/ansible
  python version = 3.7.3 (default, Dec 20 2019, 18:57:59) [GCC 8.3.0]
Using /etc/ansible/ansible.cfg as config file
META: ran handlers
localhost | CHANGED => {
    "changed": true,
    "device": null,
    "volume": {
        "attachment_set": {
            "attach_time": null,
            "device": null,
            "instance_id": null,
            "status": null
        },
        "create_time": "2020-04-01T20:31:38.620Z",
        "encrypted": null,
        "id": "vol-29e31b6d",
        "iops": 100,
        "size": 5,
        "snapshot_id": "",
        "status": "available",
        "tags": {},
        "type": "gp2",
        "zone": "eu-west-2a"
    },
    "volume_id": "vol-29e31b6d",
    "volume_type": "gp2"
}

[tremble]

We have a helper for this.
https://github.com/ansible-collections/amazon.aws/blob/master/plugins/module_utils/ec2.py#L370

Rather than copy and paste you should be able to do

from ansible_collections.amazon.aws.plugins.module_utils.ec2 import ec2_connect

and then replace from line 544 through 553 (original line numbers) with just

    ec2 = ec2_connect(module)

[tremble]

If this isn't merged first, then this would be fixed by the boto3 migration:

resolved_by #53

[ansibullbot]

cc @jillr @lwade @s-hertel @wimnat
click here for bot help

[tremble]

Thanks for taking the time to submit this PR. With the migration to boto3 (#53) support for specifying the EC2 endpoint should now be in place.