samtranslator/model/preferences/deployment_preference.py

from collections import namedtuple

from samtranslator.model.exceptions import InvalidResourceException

"""
:param deployment_type: There are two types of deployments at the moment: Linear and Canary.
    There is a default percentage of traffic that is routed to the new function's version for a 30 minute bake
    period after which the alias will 100% be routed to the new function version.
    Linear deployment type means that every 10 minutes 10% more traffic will be routed to the new function
    version.
:param pre_traffic_hook: A lambda function reference that will be used to test the new function version before
    any traffic is shifted to it at all. If his pre_traffic_hook fails the lambda deployment stops leaving
    nothing unchanged for the customer's production traffic (lambda alias still pointed ot the old version)
:param post_traffic_hook: A lambda function reference that will be used to test the new function version after
    all traffic has been shifted for the alias to be 100% pointing to the new function version. If this test
    fails CodeDeploy is in charge of rolling back the deployment meaning 100% shifting traffic back to the old
    version.
:param alarms: A list of Cloudwatch Alarm references that if ever in the alarm state during a deployment (or
    before a deployment starts) cause the deployment to fail and rollback.
:param role: An IAM role ARN that CodeDeploy will use for traffic shifting, an IAM role will not be created if
    this is supplied
:param enabled: Whether this deployment preference is enabled (true by default)
:param trigger_configurations: Information about triggers associated with the deployment group. Duplicates are
    not allowed.
"""
DeploymentPreferenceTuple = namedtuple(
    "DeploymentPreferenceTuple",
    [
        "deployment_type",
        "pre_traffic_hook",
        "post_traffic_hook",
        "alarms",
        "enabled",
        "role",
        "trigger_configurations",
        "condition",
    ],
)


class DeploymentPreference(DeploymentPreferenceTuple):
    """
    The DeploymentPreference object representing the customer's lambda deployment preferences.
    Each parameter controls what happens whenever a customer wants to update their lambda function.
    The data is "immutable".
    """

    @classmethod
    def from_dict(cls, logical_id, deployment_preference_dict, condition=None):  # type: ignore[no-untyped-def]
        """
        :param logical_id: the logical_id of the resource that owns this deployment preference
        :param deployment_preference_dict: the dict object taken from the SAM template
        :param condition: condition on this deployment preference
        :return:
        """
        enabled = deployment_preference_dict.get("Enabled", True)
        enabled = False if enabled in ["false", "False"] else enabled

        if not enabled:
            return DeploymentPreference(None, None, None, None, False, None, None, None)

        if "Type" not in deployment_preference_dict:
            raise InvalidResourceException(logical_id, "'DeploymentPreference' is missing required Property 'Type'")

        deployment_type = deployment_preference_dict["Type"]
        hooks = deployment_preference_dict.get("Hooks", {})
        if not isinstance(hooks, dict):
            raise InvalidResourceException(
                logical_id, "'Hooks' property of 'DeploymentPreference' must be a dictionary"
            )

        pre_traffic_hook = hooks.get("PreTraffic", None)
        post_traffic_hook = hooks.get("PostTraffic", None)
        alarms = deployment_preference_dict.get("Alarms", None)
        role = deployment_preference_dict.get("Role", None)
        trigger_configurations = deployment_preference_dict.get("TriggerConfigurations", None)
        passthrough_condition = deployment_preference_dict.get("PassthroughCondition", False)

        return DeploymentPreference(
            deployment_type,
            pre_traffic_hook,
            post_traffic_hook,
            alarms,
            enabled,
            role,
            trigger_configurations,
            condition if passthrough_condition else None,
        )