@Slf4j
@Service
public class GridFsManager implements InitializingBean {
    private final Environment environment;
    private final MongoDatabase db;
    private boolean available;
    private final Map<String, GridFSBucket> bucketCache = Maps.newConcurrentMap();
    public static final String LOG_BUCKET = "log";
    public static final String CONTAINER_BUCKET = "container";
    public GridFsManager(Environment environment, @Autowired(required = false) MongoTemplate mongoTemplate) {
        this.environment = environment;
        if (mongoTemplate != null) {
            this.db = mongoTemplate.getDb();
        } else {
            this.db = null;
        }
    }
    /**
     * 是否可用
     * @return true：可用；false：不可用
     */
    public boolean available() {
        return available;
    }
    //......
    private GridFSBucket getBucket(String bucketName) {
        return bucketCache.computeIfAbsent(bucketName, ignore -> GridFSBuckets.create(db, bucketName));
    }
    @Override
    public void afterPropertiesSet() throws Exception {
        String enable = environment.getProperty(PowerJobServerConfigKey.MONGODB_ENABLE, Boolean.FALSE.toString());
        available = Boolean.TRUE.toString().equals(enable) && db != null;
        log.info("[GridFsManager] available: {}, db: {}", available, db);
    }
}

/**
     * 存儲(chǔ)文件到 GridFS
     * @param localFile 本地文件
     * @param bucketName 桶名稱
     * @param fileName GirdFS中的文件名稱
     * @throws IOException 異常
     */
    public void store(File localFile, String bucketName, String fileName) throws IOException {
        if (available()) {
            GridFSBucket bucket = getBucket(bucketName);
            try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream(localFile))) {
                bucket.uploadFromStream(fileName, bis);
            }
        }
    }

/**
     * 從 GridFS 下載文件
     * @param targetFile 下載的目標(biāo)文件（本地文件）
     * @param bucketName 桶名稱
     * @param fileName GirdFS中的文件名稱
     * @throws IOException 異常
     */
    public void download(File targetFile, String bucketName, String fileName) throws IOException {
        if (available()) {
            GridFSBucket bucket = getBucket(bucketName);
            try (GridFSDownloadStream gis = bucket.openDownloadStream(fileName);
                 BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(targetFile))
            ) {
                byte[] buffer = new byte[1024];
                int bytes = 0;
                while ((bytes = gis.read(buffer)) != -1) {
                    bos.write(buffer, 0, bytes);
                }
                bos.flush();
            }
        }
    }

/**
     * 刪除幾天前的文件
     * @param bucketName 桶名稱
     * @param day 日期偏移量，單位 天
     */
    public void deleteBefore(String bucketName, int day) {
        Stopwatch sw = Stopwatch.createStarted();
        Date date = DateUtils.addDays(new Date(), -day);
        GridFSBucket bucket = getBucket(bucketName);
        Bson filter = Filters.lt("uploadDate", date);
        // 循環(huán)刪除性能很差？我猜你肯定沒(méi)看過(guò)官方實(shí)現(xiàn)[狗頭]：org.springframework.data.mongodb.gridfs.GridFsTemplate.delete
        bucket.find(filter).forEach((Consumer<GridFSFile>) gridFSFile -> {
            ObjectId objectId = gridFSFile.getObjectId();
            try {
                bucket.delete(objectId);
                log.info("[GridFsManager] deleted {}#{}", bucketName, objectId);
            }catch (Exception e) {
                log.error("[GridFsManager] deleted {}#{} failed.", bucketName, objectId, e);
            }
        });
        log.info("[GridFsManager] clean bucket({}) successfully, delete all files before {}, using {}.", bucketName, date, sw.stop());
    }

public boolean exists(String bucketName, String fileName) {
        GridFSBucket bucket = getBucket(bucketName);
        GridFSFindIterable files = bucket.find(Filters.eq("filename", fileName));
        try {
            GridFSFile first = files.first();
            return first != null;
        }catch (Exception ignore) {
        }
        return false;
    }

@Async(PJThreadPool.BACKGROUND_POOL)
    public void sync(Long instanceId) {
        Stopwatch sw = Stopwatch.createStarted();
        try {
            // 先持久化到本地文件
            File stableLogFile = genStableLogFile(instanceId);
            // 將文件推送到 MongoDB
            if (gridFsManager.available()) {
                try {
                    gridFsManager.store(stableLogFile, GridFsManager.LOG_BUCKET, genMongoFileName(instanceId));
                    log.info("[InstanceLog-{}] push local instanceLogs to mongoDB succeed, using: {}.", instanceId, sw.stop());
                }catch (Exception e) {
                    log.warn("[InstanceLog-{}] push local instanceLogs to mongoDB failed.", instanceId, e);
                }
            }
        }catch (Exception e) {
            log.warn("[InstanceLog-{}] sync local instanceLogs failed.", instanceId, e);
        }
        // 刪除本地?cái)?shù)據(jù)庫(kù)數(shù)據(jù)
        try {
            instanceId2LastReportTime.remove(instanceId);
            CommonUtils.executeWithRetry0(() -> localInstanceLogRepository.deleteByInstanceId(instanceId));
            log.info("[InstanceLog-{}] delete local instanceLog successfully.", instanceId);
        }catch (Exception e) {
            log.warn("[InstanceLog-{}] delete local instanceLog failed.", instanceId, e);
        }
    }