Merge pull request #106 from aarcro/103_ec2_roles

#103 Create roles with no policies

stacker_blueprints/iam_roles.py

@@ -0,0 +1,108 @@
+from stacker.blueprints.base import Blueprint
+
+from troposphere import (
+    GetAtt,
+    Output,
+    Ref,
+    iam,
+)
+
+from awacs.aws import Policy
+from awacs.helpers.trust import (
+    get_default_assumerole_policy,
+    get_lambda_assumerole_policy
+)
+
+
+class Roles(Blueprint):
+    VARIABLES = {
+        "Ec2Roles": {
+            "type": list,
+            "description": "names of ec2 roles to create",
+            "default": [],
+        },
+        "LambdaRoles": {
+            "type": list,
+            "description": "names of lambda roles to create",
+            "default": [],
+        },
+    }
+
+    def __init__(self, *args, **kwargs):
+        super(Roles, self).__init__(*args, **kwargs)
+        self.roles = []
+        self.policies = []
+
+    def create_role(self, name, assumerole_policy):
+        t = self.template
+
+        role = t.add_resource(
+            iam.Role(
+                name,
+                AssumeRolePolicyDocument=assumerole_policy,
+            )
+        )
+
+        t.add_output(
+            Output(name + "RoleName", Value=Ref(role))
+        )
+        t.add_output(
+            Output(name + "RoleArn", Value=GetAtt(role.title, "Arn"))
+        )
+
+        self.roles.append(role)
+        return role
+
+    def create_ec2_role(self, name):
+        return self.create_role(name, get_default_assumerole_policy())
+
+    def create_lambda_role(self, name):
+        return self.create_role(name, get_lambda_assumerole_policy())
+
+    def generate_policy_statements(self):
+        """Should be overridden on a subclass to create policy statements.
+
+        By subclassing this blueprint, and overriding this method to generate
+        a list of :class:`awacs.aws.Statement` types, a
+        :class:`troposphere.iam.PolicyType` will be created and attached to
+        the roles specified here.
+
+        If not specified, no Policy will be created.
+        """
+
+        return []
+
+    def create_policy(self, name):
+        statements = self.generate_policy_statements()
+        if not statements:
+            return
+
+        t = self.template
+        policy_prefix = self.context.get_fqn(self.name)
+
+        policy = t.add_resource(
+            iam.PolicyType(
+                "{}Policy".format(name),
+                PolicyName="{}-{}-policy".format(policy_prefix, name),
+                PolicyDocument=Policy(
+                    Statement=statements,
+                ),
+                Roles=[Ref(role) for role in self.roles],
+            )
+        )
+
+        t.add_output(
+            Output(name + "PolicyName", Value=Ref(policy))
+        )
+        self.policies.append(policy)
+
+    def create_template(self):
+        variables = self.get_variables()
+
+        for role in variables['Ec2Roles']:
+            self.create_ec2_role(role)
+
+        for role in variables['LambdaRoles']:
+            self.create_lambda_role(role)
+
+        self.create_policy()