ConstReadonlyCOST_OPTIMIZED: "COST_OPTIMIZED"COST_OPTIMIZED to prefer spot instance.
ReadonlyPOLICY_UNSPECIFIED: "POLICY_UNSPECIFIED"UNSPECIFIED if no value is set by the caller. Consult endpoint docs to learn about the defaults that kick in if UNSPECIFIED.
Protobuf enums should start with INVALID/UNSPECIFIED=0 (https://github.com/uber/prototool/tree/dev/style#enums), but since proto enum values must be unique within a proto package so protobuf recommends prefixing enum with enum name (https://buf.build/docs/lint-checkers/#enum_value_prefix). We do not want to do that because it makes for unergonomic customer facing JSON api {"spot_instance_policy": "ENDPOINT_SPOT_INSTANCE_POLICY_UNSPECIFIED"}.
As a compromise between protobuf rules (i.e., package unique enum values) and JSON friendliness, we prevent UNSPECIFIED collision but hope that the rest of the enums do not collide.
This follows Google APIs: https://cloud.google.com/apis/design/design_patterns#enum_default_value.
ReadonlyRELIABILITY_OPTIMIZED: "RELIABILITY_OPTIMIZED"RELIABILITY_OPTIMIZED to prefer on demand instance.
EndpointSpotInstancePolicy configures whether the endpoint should use spot instances.
The breakdown of how the EndpointSpotInstancePolicy converts to per cloud configurations is:
+-------+--------------------------------------+--------------------------------+ | Cloud | COST_OPTIMIZED | RELIABILITY_OPTIMIZED | +-------+--------------------------------------+--------------------------------+ | AWS | On Demand Driver with Spot Executors | On Demand Driver and Executors | | AZURE | On Demand Driver and Executors | On Demand Driver and Executors | +-------+--------------------------------------+--------------------------------+