#!/bin/bash
# /opt/topfans/loadtest/monitor/sample.sh
# 后台采样,写到 metrics-feed.jsonl
set -e

OUT="/opt/topfans/loadtest/metrics-feed.jsonl"
INTERVAL=${INTERVAL:-5}
PG_CONTAINER=$(docker ps --filter 'name=postgres' --format '{{.Names}}' | grep -v exporter | head -1)
[ -z "$PG_CONTAINER" ] && { echo "❌ 找不到 postgres 容器"; exit 1; }
export PGPASSWORD="${DB_PASSWORD:-postgres123}"

echo "📊 sampling to $OUT every ${INTERVAL}s, pid $$"
: > "$OUT"
while true; do
    TS=$(date +%s)
    PG_ACTIVE=$(docker exec -e PGPASSWORD="$PGPASSWORD" "$PG_CONTAINER" psql -U postgres -d topfans -tA -c "SELECT count(*) FROM pg_stat_activity WHERE state='active'" 2>/dev/null || echo 0)
    DISK_FREE=$(df -B1G /opt | tail -1 | awk '{print $4}')
    OOM=$(docker events --filter event=oom --since 5s --until 0s --format '{{.Actor.Attributes.name}}' 2>/dev/null | head -1)
    if [ -n "$OOM" ]; then
        OOM_FLAG="true"
        OOM_NAME="$OOM"
    else
        OOM_FLAG="false"
        OOM_NAME=""
    fi
    echo "$TS pg_active=$PG_ACTIVE disk_free=$DISK_FREE oom=$OOM_FLAG oom_container=$OOM_NAME" >> "$OUT"
    sleep "$INTERVAL"
done