Support Amazon S3 Dual-Stack Endpoints in aws_module (#43403)

* Use https:// for docs.aws.amazon.com in aws_s3 module

* Support Amazon S3 Dual-Stack Endpoints in aws_module

The default S3 endpoint only resolves to IPv4 addresses. By enabling
the dual-stack endpoint IPv6 too get added as an option.

lib/ansible/modules/cloud/amazon/aws_s3.py

@@ -114,7 +114,7 @@ options:
         Boolean or one of [always, never, different], true is equal to 'always' and false is equal to 'never', new in 2.0.
         When this is set to 'different', the md5 sum of the local file is compared with the 'ETag' of the object/key in S3.
         The ETag may or may not be an MD5 digest of the object data. See the ETag response header here
-        U(http://docs.aws.amazon.com/AmazonS3/latest/API/RESTCommonResponseHeaders.html)
+        U(https://docs.aws.amazon.com/AmazonS3/latest/API/RESTCommonResponseHeaders.html)
     default: 'always'
     aliases: ['force']
     version_added: "1.2"
@@ -133,6 +133,13 @@ options:
     description:
       - S3 URL endpoint for usage with Ceph, Eucalypus, fakes3, etc.  Otherwise assumes AWS
     aliases: [ S3_URL ]
+  dualstack:
+    description:
+      - Enables Amazon S3 Dual-Stack Endpoints, allowing S3 communications using both IPv4 and IPv6.
+      - Requires at least botocore version 1.4.45.
+    type: bool
+    default: "no"
+    version_added: "2.7"
   rgw:
     description:
       - Enable Ceph RGW S3 support. This option requires an explicit url via s3_url.
@@ -649,6 +656,12 @@ def get_s3_connection(module, aws_connect_kwargs, location, rgw, s3_url, sig_4=F
             params['config'] = botocore.client.Config(signature_version='s3v4')
         elif module.params['mode'] in ('get', 'getstr') and sig_4:
             params['config'] = botocore.client.Config(signature_version='s3v4')
+        if module.params['dualstack']:
+            dualconf = botocore.client.Config(s3={'use_dualstack_endpoint': True})
+            if 'config' in params:
+                params['config'] = params['config'].merge(dualconf)
+            else:
+                params['config'] = dualconf
     return boto3_conn(**params)
 
 
@@ -673,6 +686,7 @@ def main():
             prefix=dict(default=""),
             retries=dict(aliases=['retry'], type='int', default=0),
             s3_url=dict(aliases=['S3_URL']),
+            dualstack=dict(default='no', type='bool'),
             rgw=dict(default='no', type='bool'),
             src=dict(),
             ignore_nonexistent_bucket=dict(default=False, type='bool'),
@@ -706,6 +720,7 @@ def main():
     prefix = module.params.get('prefix')
     retries = module.params.get('retries')
     s3_url = module.params.get('s3_url')
+    dualstack = module.params.get('dualstack')
     rgw = module.params.get('rgw')
     src = module.params.get('src')
     ignore_nonexistent_bucket = module.params.get('ignore_nonexistent_bucket')
@@ -744,6 +759,12 @@ def main():
     if not s3_url and 'S3_URL' in os.environ:
         s3_url = os.environ['S3_URL']
 
+    if dualstack and s3_url:
+        module.fail_json(msg='dualstack only applies to AWS S3')
+
+    if dualstack and not module.botocore_at_least('1.4.45'):
+        module.fail_json(msg='dualstack requires botocore >= 1.4.45')
+
     # rgw requires an explicit url
     if rgw and not s3_url:
         module.fail_json(msg='rgw flavour requires s3_url')