Add configuration entrypoint for ECS

judoscale/core/config.py

@@ -3,6 +3,8 @@
 from collections import UserDict
 from typing import Mapping
 
+import requests
+
 from judoscale.core.logger import logger
 
 DEFAULTS = {"REPORT_INTERVAL_SECONDS": 10, "LOG_LEVEL": "WARN"}
@@ -49,6 +51,8 @@ def initialize(cls, env: Mapping = os.environ):
             return cls.for_heroku(env)
         elif env.get("RENDER_INSTANCE_ID"):
             return cls.for_render(env)
+        elif env.get("ECS_CONTAINER_METADATA_URI_V4"):
+            return cls.for_ecs(env)
         else:
             return cls(None, "", env)
 
@@ -71,6 +75,18 @@ def for_render(cls, env: Mapping):
         api_base_url = f"https://adapter.judoscale.com/api/{service_id}"
         return cls(runtime_container, api_base_url, env)
 
+    @classmethod
+    def for_ecs(cls, env: Mapping):
+        container_metadata = requests.get(env["ECS_CONTAINER_METADATA_URI_V4"]).json()
+        service_name = container_metadata["DockerName"]
+        instance = container_metadata["DockerId"]
+
+        # All ECS containers have to be manually assigned as web instances,
+        # because ECS does not distinguish between web and worker instances.
+        runtime_container = RuntimeContainer(service_name, instance, "web")
+        api_base_url = env.get("JUDOSCALE_URL")
+        return cls(runtime_container, api_base_url, env)
+
     @property
     def is_enabled(self) -> bool:
         return bool(self["API_BASE_URL"])

pyproject.toml

@@ -31,6 +31,7 @@ black = "^22.12.0"
 isort = "^5.11.2"
 flake8 = { version = "^6.0.0", python = ">=3.8.1,<4.0.0" }
 pytest = "^7.2.2"
+responses = "^0.23.1"
 
 [tool.poetry.extras]
 django = ["django"]

tests/test_config.py

@@ -1,5 +1,19 @@
+import pytest
+import responses
+
 from judoscale.core.config import Config, RuntimeContainer
 
+ecs_response = {
+    "DockerId": "b25c2505a33f4b3ab8673c3200c2f245-2750272591",
+    "DockerName": "backend",
+}
+
+
+@pytest.fixture
+def mocked_responses():
+    with responses.RequestsMock() as rsps:
+        yield rsps
+
 
 class TestConfig:
     def test_on_heroku(self):
@@ -31,6 +45,29 @@ def test_on_render(self):
         assert config["LOG_LEVEL"] == "WARN"
         assert config["API_BASE_URL"] == "https://adapter.judoscale.com/api/srv-123"
 
+    def test_on_ecs(self, mocked_responses):
+        mocked_responses.get(
+            "https://127.0.0.1/api/123456",
+            status=200,
+            json=ecs_response,
+        )
+
+        fake_env = {
+            "ECS_CONTAINER_METADATA_URI_V4": "https://127.0.0.1/api/123456",
+            "JUDOSCALE_URL": "https://adapter.judoscale.com/api/srv-123",
+            "LOG_LEVEL": "WARN",
+        }
+        config = Config.for_ecs(fake_env)
+
+        assert config["RUNTIME_CONTAINER"].service_name == "backend"
+        assert (
+            config["RUNTIME_CONTAINER"].instance
+            == "b25c2505a33f4b3ab8673c3200c2f245-2750272591"
+        )
+        assert config["RUNTIME_CONTAINER"].service_type == "web"
+        assert config["LOG_LEVEL"] == "WARN"
+        assert config["API_BASE_URL"] == "https://adapter.judoscale.com/api/srv-123"
+
     def test_is_enabled(self):
         config = Config(None, "", {})
         assert not config.is_enabled