feat(validate): Add profile and region options (aws#582)

Currently, `sam validate` requires AWS Creds (due to the SAM Translator).
This commits adds the ability to pass in the credientials through a profile
that is configured through `aws configure`.

samcli/commands/validate/validate.py

@@ -4,11 +4,12 @@
 import os
 
 import boto3
+from botocore.exceptions import NoCredentialsError
 import click
 from samtranslator.translator.managed_policy_translator import ManagedPolicyLoader
 
-
-from samcli.cli.main import pass_context, common_options as cli_framework_options
+from samcli.commands.exceptions import UserException
+from samcli.cli.main import pass_context, common_options as cli_framework_options, aws_creds_options
 from samcli.commands.local.cli_common.options import template_common_option as template_option
 from samcli.commands.local.cli_common.user_exceptions import InvalidSamTemplateException, SamTemplateNotFoundException
 from samcli.yamlhelper import yaml_parse
@@ -19,6 +20,7 @@
 @click.command("validate",
                short_help="Validate an AWS SAM template.")
 @template_option
+@aws_creds_options
 @cli_framework_options
 @pass_context
 def cli(ctx, template):
@@ -43,6 +45,8 @@ def do_cli(ctx, template):
     except InvalidSamDocumentException as e:
         click.secho("Template provided at '{}' was invalid SAM Template.".format(template), bg='red')
         raise InvalidSamTemplateException(str(e))
+    except NoCredentialsError as e:
+        raise UserException("AWS Credentials are required. Please configure your credentials.")
 
     click.secho("{} is a valid SAM Template".format(template), fg='green')
 

tests/unit/commands/validate/test_cli.py

@@ -1,6 +1,9 @@
 from unittest import TestCase
 from mock import Mock, patch
 
+from botocore.exceptions import NoCredentialsError
+
+from samcli.commands.exceptions import UserException
 from samcli.commands.local.cli_common.user_exceptions import SamTemplateNotFoundException, InvalidSamTemplateException
 from samcli.commands.validate.lib.exceptions import InvalidSamDocumentException
 from samcli.commands.validate.validate import do_cli, _read_sam_file
@@ -47,6 +50,21 @@ def test_template_fails_validation(self, read_sam_file_patch, click_patch, templ
             do_cli(ctx=None,
                    template=template_path)
 
+    @patch('samcli.commands.validate.validate.SamTemplateValidator')
+    @patch('samcli.commands.validate.validate.click')
+    @patch('samcli.commands.validate.validate._read_sam_file')
+    def test_no_credentials_provided(self, read_sam_file_patch, click_patch, template_valiadator):
+        template_path = 'path_to_template'
+        read_sam_file_patch.return_value = {"a": "b"}
+
+        is_valid_mock = Mock()
+        is_valid_mock.is_valid.side_effect = NoCredentialsError
+        template_valiadator.return_value = is_valid_mock
+
+        with self.assertRaises(UserException):
+            do_cli(ctx=None,
+                   template=template_path)
+
     @patch('samcli.commands.validate.validate.SamTemplateValidator')
     @patch('samcli.commands.validate.validate.click')
     @patch('samcli.commands.validate.validate._read_sam_file')