add buildbot extension for autoscaling nix builders

buildbot-ext/buildbot_autoscale_ext/telemetry.py

@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+import logging
+
+
+def get_logger(name: str) -> logging.Logger:
+    return logging.getLogger(name)
+
+
+def event(logger: logging.Logger, level: int, name: str, **fields: object) -> None:
+    logger.log(level, "%s %s", name, " ".join(f"{key}={value!r}" for key, value in fields.items()))
+
+
+def phase_message(phase: str | None, reason: str | None) -> str:
+    details: list[str] = []
+    if phase:
+        details.append(f"phase={phase}")
+    if reason:
+        details.append(f"reason={reason}")
+    return " ".join(details) if details else "no daemon details"