Add system test for NATS exporter

tests/test_export_nats.sh

@@ -6,6 +6,29 @@
 # Exit on error
 set -e
 
+# Configuration
+MIN_MESSAGES=10
+NATS_SUBJECT="glances.>"
+MESSAGE_COUNT_FILE=$(mktemp)
+echo "0" > "$MESSAGE_COUNT_FILE"
+
+# Cleanup function
+cleanup() {
+    echo "Cleaning up..."
+    # Kill subscriber if running
+    if [ -n "$SUBSCRIBER_PID" ] && kill -0 "$SUBSCRIBER_PID" 2>/dev/null; then
+        kill "$SUBSCRIBER_PID" 2>/dev/null || true
+    fi
+    # Stop and remove containers
+    docker stop nats-subscriber 2>/dev/null || true
+    docker stop nats-for-glances 2>/dev/null || true
+    docker rm nats-subscriber 2>/dev/null || true
+    docker rm nats-for-glances 2>/dev/null || true
+    # Remove temp file
+    rm -f "$MESSAGE_COUNT_FILE"
+}
+trap cleanup EXIT
+
 echo "Stop previous nats container..."
 docker stop nats-for-glances || true
 docker rm nats-for-glances || true
@@ -18,17 +41,49 @@ docker run -d \
     -p 6222:6222 \
     nats:latest
 
-# Wait for InfluxDB to be ready (5 seconds)
+# Wait for NATS to be ready (5 seconds)
 echo "Waiting for nats to start (~ 5 seconds)..."
 sleep 5
 
+# Start a NATS subscriber in the background using nats-box container
+# The subscriber will count messages received on the glances subject
+echo "Starting NATS subscriber to count messages..."
+docker run --rm --name nats-subscriber \
+    --network host \
+    natsio/nats-box:latest \
+    nats sub "$NATS_SUBJECT" 2>/dev/null | \
+    while read -r line; do
+        if [[ "$line" == *"Received"* ]] || [[ "$line" == "{"* ]]; then
+            count=$(cat "$MESSAGE_COUNT_FILE")
+            echo $((count + 1)) > "$MESSAGE_COUNT_FILE"
+        fi
+    done &
+SUBSCRIBER_PID=$!
+
+# Give the subscriber time to connect
+sleep 2
+
 # Run glances with export to nats, stopping after 10 writes
 # This will run synchronously now since we're using --stop-after
 echo "Glances to export system stats to nats (duration: ~ 20 seconds)"
 .venv/bin/python -m glances --config ./conf/glances.conf --export nats --stop-after 10 --quiet
 
-# Stop and remove the nats container
-echo "Stopping and removing nats container..."
-docker stop nats-for-glances && docker rm nats-for-glances
+# Give some time for final messages to be received
+sleep 2
+
+# Stop the subscriber
+docker stop nats-subscriber 2>/dev/null || true
+kill "$SUBSCRIBER_PID" 2>/dev/null || true
+
+# Check message count
+MESSAGE_COUNT=$(cat "$MESSAGE_COUNT_FILE")
+echo "Received $MESSAGE_COUNT messages from NATS"
+
+if [ "$MESSAGE_COUNT" -ge "$MIN_MESSAGES" ]; then
+    echo "SUCCESS: Received $MESSAGE_COUNT messages (minimum required: $MIN_MESSAGES)"
+else
+    echo "FAILURE: Received only $MESSAGE_COUNT messages (minimum required: $MIN_MESSAGES)"
+    exit 1
+fi
 
 echo "Script completed successfully!"