feat(router): Phase 1 - Circuit Breaker + /metrics/circuit-breaker endpoint

router/router.py

@@ -236,6 +236,33 @@ def select_best_gpu(candidates, reason, agent=""):
 
 
 
+
+
+# Phase 1: Circuit Breaker for GPU Hosts (Approved by Abiba)
+def is_circuit_tripped(model):
+    """Check if a GPU host is currently blacklisted."""
+    if not get_redis():
+        return False
+    return r.exists("circuit:" + model + ":open")
+
+def trip_circuit(model, duration=30):
+    """Blacklist a GPU host for a specified duration."""
+    if not get_redis():
+        return
+    key = "circuit:" + model + ":open"
+    r.set(key, 1, ex=duration)
+    r.incr("circuit:" + model + ":count")
+    log.warning("CIRCUIT_TRIPPED: %s blacklisted for %ds", model, duration)
+
+def half_open_probe(model):
+    """Check if a GPU host can be un-blacklisted."""
+    if not get_redis():
+        return True
+    key = "circuit:" + model + ":open"
+    if not r.exists(key):
+        return True  # no circuit
+    return False  # still open
+
 def route(rd, tier, agent=""):
     msgs = rd.get("messages",[]); t = estimate_tokens(msgs)
     sys = any(m.get("role")=="system" for m in msgs)
@@ -739,6 +766,24 @@ def metrics_timeseries():
             data["models"][model] = counts
     return jsonify(data)
 
+
+
+@app.route("/metrics/circuit-breaker")
+def metrics_circuit_breaker():
+    """Expose circuit breaker status per model. Phase 1."""
+    result = {}
+    if r:
+        for model in GPU_URLS:
+            key = "circuit:" + model + ":open"
+            duration = r.ttl(key)
+            trip_count = int(r.get("circuit:" + model + ":count") or 0)
+            result[model] = {
+                "tripped": r.exists(key),
+                "remaining_ttl": duration,
+                "trip_count": trip_count
+            }
+    return jsonify(result)
+
 @app.route("/stream")
 def stream():
     def ev():