[V1][Metrics] add support for kv event publishing (#16750)

Signed-off-by: alec-flowers <aflowers@nvidia.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Co-authored-by: Mark McLoughlin <markmc@redhat.com>

examples/online_serving/kv_events.sh

@@ -0,0 +1,86 @@
+#!/bin/bash
+# This file demonstrates the KV cache event publishing
+# We will launch a vllm instances configured to publish KV cache
+# events and launch a simple subscriber to log those events.
+
+set -xe
+
+echo "🚧🚧 Warning: The usage of KV cache events is experimental and subject to change 🚧🚧"
+sleep 1
+
+MODEL_NAME=${HF_MODEL_NAME:-meta-llama/Meta-Llama-3.1-8B-Instruct}
+
+# Trap the SIGINT signal (triggered by Ctrl+C)
+trap 'cleanup' INT
+
+# Cleanup function
+cleanup() {
+    echo "Caught Ctrl+C, cleaning up..."
+    # Cleanup commands
+    pgrep python | xargs kill -9
+    pkill -f python
+    echo "Cleanup complete. Exiting."
+    exit 0
+}
+
+export VLLM_HOST_IP=$(hostname -I | awk '{print $1}')
+
+# a function that waits vLLM server to start
+wait_for_server() {
+  local port=$1
+  timeout 1200 bash -c "
+    until curl -s localhost:${port}/v1/completions > /dev/null; do
+      sleep 1
+    done" && return 0 || return 1
+}
+
+vllm serve $MODEL_NAME \
+    --port 8100 \
+    --max-model-len 100 \
+    --enforce-eager \
+    --gpu-memory-utilization 0.8 \
+    --trust-remote-code \
+    --kv-events-config \
+    '{"enable_kv_cache_events": true, "publisher": "zmq", "topic": "kv-events"}' &
+
+wait_for_server 8100
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
+python3 "$SCRIPT_DIR/kv_events_subscriber.py" &
+sleep 1
+
+# serve two example requests
+output1=$(curl -X POST -s http://localhost:8100/v1/completions \
+-H "Content-Type: application/json" \
+-d '{
+"model": "'"$MODEL_NAME"'",
+"prompt": "Explain quantum computing in simple terms a 5-year-old could understand.",
+"max_tokens": 80,
+"temperature": 0
+}')
+
+output2=$(curl -X POST -s http://localhost:8100/v1/completions \
+-H "Content-Type: application/json" \
+-d '{
+"model": "'"$MODEL_NAME"'",
+"prompt": "Explain quantum computing in simple terms a 50-year-old could understand.",
+"max_tokens": 80,
+"temperature": 0
+}')
+
+# Cleanup commands
+pkill -9 -u "$USER" -f python
+pkill -9 -u "$USER" -f vllm
+
+sleep 1
+
+echo "Cleaned up"
+
+# Print the outputs of the curl requests
+echo ""
+echo "Output of first request: $output1"
+echo "Output of second request: $output2"
+
+echo "🎉🎉 Successfully finished 2 test requests! 🎉🎉"
+echo ""