feat(telemetry): add portable local telemetry plane

tests/test_telemetry_plane_prepare.py

@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+import importlib.util
+import stat
+from pathlib import Path
+from types import ModuleType
+
+import pytest
+
+
+def _prepare_module() -> ModuleType:
+    path = (
+        Path(__file__).resolve().parents[1]
+        / "deploy"
+        / "telemetry-plane"
+        / "prepare.py"
+    )
+    specification = importlib.util.spec_from_file_location(
+        "mission_core_telemetry_prepare",
+        path,
+    )
+    assert specification is not None
+    assert specification.loader is not None
+    module = importlib.util.module_from_spec(specification)
+    specification.loader.exec_module(module)
+    return module
+
+
+prepare = _prepare_module()
+
+
+def test_initialize_environment_generates_private_unique_secrets(
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    env_path = tmp_path / ".env"
+    monkeypatch.setattr(prepare, "ENV_PATH", env_path)
+
+    prepare._initialize_environment("192.0.2.15")
+
+    values = dict(
+        line.split("=", 1)
+        for line in env_path.read_text(encoding="utf-8").splitlines()
+    )
+    assert values["MISSIONCORE_MQTT_BIND_ADDRESS"] == "192.0.2.15"
+    secrets = {
+        values["MISSIONCORE_DB_PASSWORD"],
+        values["MISSIONCORE_MQTT_INGEST_PASSWORD"],
+        values["MISSIONCORE_MQTT_WORKER_006_PASSWORD"],
+    }
+    assert len(secrets) == 3
+    assert all(len(secret) >= 40 for secret in secrets)
+    assert stat.S_IMODE(env_path.stat().st_mode) == 0o600
+
+
+def test_initialize_environment_refuses_to_replace_credentials(
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    env_path = tmp_path / ".env"
+    env_path.write_text("existing=true\n", encoding="utf-8")
+    monkeypatch.setattr(prepare, "ENV_PATH", env_path)
+
+    with pytest.raises(RuntimeError, match="refusing to overwrite"):
+        prepare._initialize_environment("127.0.0.1")
+
+    assert env_path.read_text(encoding="utf-8") == "existing=true\n"