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本文主要研究一下PowerJob的AliOssService
DFsService
tech/powerjob/server/extension/dfs/DFsService.java
public interface DFsService {/*** 存储文件* @param storeRequest 存储请求* @throws IOException 异常*/void store(StoreRequest storeRequest) throws IOException;/*** 下载文件* @param downloadRequest 文件下载请求* @throws IOException 异常*/void download(DownloadRequest downloadRequest) throws IOException;/*** 获取文件元信息* @param fileLocation 文件位置* @return 存在则返回文件元信息* @throws IOException 异常*/Optional<FileMeta> fetchFileMeta(FileLocation fileLocation) throws IOException;/*** 清理 powerjob 认为“过期”的文件* 部分存储系统自带生命周期管理（如阿里云OSS，则不需要单独实现该方法）* @param bucket bucket* @param days 天数，需要清理超过 X 天的文件*/default void cleanExpiredFiles(String bucket, int days) {}
}
DFsService接口定义了store、download、fetchFileMeta、cleanExpiredFiles方法
AbstractDFsService
tech/powerjob/server/persistence/storage/AbstractDFsService.java
@Slf4j
public abstract class AbstractDFsService implements DFsService, ApplicationContextAware, DisposableBean {protected ApplicationContext applicationContext;public AbstractDFsService() {log.info("[DFsService] invoke [{}]'s constructor", this.getClass().getName());}abstract protected void init(ApplicationContext applicationContext);protected static final String PROPERTY_KEY = "oms.storage.dfs";protected static String fetchProperty(Environment environment, String dfsType, String key) {String pKey = String.format("%s.%s.%s", PROPERTY_KEY, dfsType, key);return environment.getProperty(pKey);}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;log.info("[DFsService] invoke [{}]'s setApplicationContext", this.getClass().getName());init(applicationContext);}
}
AbstractDFsService声明实现DFsService、ApplicationContextAware、DisposableBean接口，它在setApplicationContext方法执行了init
AliOssService
tech/powerjob/server/persistence/storage/impl/AliOssService.java
@Slf4j
@Priority(value = Integer.MAX_VALUE - 1)
@Conditional(AliOssService.AliOssCondition.class)
public class AliOssService extends AbstractDFsService {private static final String TYPE_ALI_OSS = "alioss";private static final String KEY_ENDPOINT = "endpoint";private static final String KEY_BUCKET = "bucket";private static final String KEY_CREDENTIAL_TYPE = "credential_type";private static final String KEY_AK = "ak";private static final String KEY_SK = "sk";private static final String KEY_TOKEN = "token";private OSS oss;private String bucket;private static final int DOWNLOAD_PART_SIZE = 10240;private static final String NO_SUCH_KEY = "NoSuchKey";//......void initOssClient(String endpoint, String bucket, String mode, String ak, String sk, String token) throws Exception {log.info("[AliOssService] init OSS by config: endpoint={},bucket={},credentialType={},ak={},sk={},token={}", endpoint, bucket, mode, ak, sk, token);if (StringUtils.isEmpty(bucket)) {throw new IllegalArgumentException("'oms.storage.dfs.alioss.bucket' can't be empty, please creat a bucket in aliyun oss console then config it to powerjob");}this.bucket = bucket;CredentialsProvider credentialsProvider;CredentialType credentialType = CredentialType.parse(mode);switch (credentialType) {case PWD:credentialsProvider = new DefaultCredentialProvider(ak, sk, token);break;case SYSTEM_PROPERTY:credentialsProvider = CredentialsProviderFactory.newSystemPropertiesCredentialsProvider();break;default:credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();}this.oss = new OSSClientBuilder().build(endpoint, credentialsProvider);log.info("[AliOssService] initialize successfully, THIS_WILL_BE_THE_STORAGE_LAYER.");}//......
}
AliOssService继承了AbstractDFsService
store
@Overridepublic void store(StoreRequest storeRequest) throws IOException {ObjectMetadata objectMetadata = new ObjectMetadata();PutObjectRequest putObjectRequest = new PutObjectRequest(bucket, parseFileName(storeRequest.getFileLocation()), storeRequest.getLocalFile(), objectMetadata);oss.putObject(putObjectRequest);}
store方法创建PutObjectRequest，使用oss.putObject进行上传
download
@Overridepublic void download(DownloadRequest downloadRequest) throws IOException {FileLocation dfl = downloadRequest.getFileLocation();DownloadFileRequest downloadFileRequest = new DownloadFileRequest(bucket, parseFileName(dfl), downloadRequest.getTarget().getAbsolutePath(), DOWNLOAD_PART_SIZE);try {FileUtils.forceMkdirParent(downloadRequest.getTarget());oss.downloadFile(downloadFileRequest);} catch (Throwable t) {ExceptionUtils.rethrow(t);}}
download方法则根据DownloadRequest指定的FileLocation创建DownloadFileRequest，然后通过oss.downloadFile(downloadFileRequest)进行下载
fetchFileMeta
@Overridepublic Optional<FileMeta> fetchFileMeta(FileLocation fileLocation) throws IOException {try {ObjectMetadata objectMetadata = oss.getObjectMetadata(bucket, parseFileName(fileLocation));return Optional.ofNullable(objectMetadata).map(ossM -> {Map<String, Object> metaInfo = Maps.newHashMap();metaInfo.putAll(ossM.getRawMetadata());if (ossM.getUserMetadata() != null) {metaInfo.putAll(ossM.getUserMetadata());}return new FileMeta().setLastModifiedTime(ossM.getLastModified()).setLength(ossM.getContentLength()).setMetaInfo(metaInfo);});} catch (OSSException oe) {String errorCode = oe.getErrorCode();if (NO_SUCH_KEY.equalsIgnoreCase(errorCode)) {return Optional.empty();}ExceptionUtils.rethrow(oe);}return Optional.empty();}
fetchFileMeta方法通过oss.getObjectMetadata获取ObjectMetadata
cleanExpiredFiles
@Overridepublic void cleanExpiredFiles(String bucket, int days) {/*阿里云 OSS 自带生命周期管理，请参考文档进行配置，代码层面不进行实现（浪费服务器资源）https://help.aliyun.com/zh/oss/user-guide/overview-54阿里云 OSS 自带生命周期管理，请参考文档进行配置，代码层面不进行实现（浪费服务器资源）https://help.aliyun.com/zh/oss/user-guide/overview-54阿里云 OSS 自带生命周期管理，请参考文档进行配置，代码层面不进行实现（浪费服务器资源）https://help.aliyun.com/zh/oss/user-guide/overview-54*/}
cleanExpiredFiles则是空操作
init
protected void init(ApplicationContext applicationContext) {Environment environment = applicationContext.getEnvironment();String endpoint = fetchProperty(environment, TYPE_ALI_OSS, KEY_ENDPOINT);String bkt = fetchProperty(environment, TYPE_ALI_OSS, KEY_BUCKET);String ct = fetchProperty(environment, TYPE_ALI_OSS, KEY_CREDENTIAL_TYPE);String ak = fetchProperty(environment, TYPE_ALI_OSS, KEY_AK);String sk = fetchProperty(environment, TYPE_ALI_OSS, KEY_SK);String token = fetchProperty(environment, TYPE_ALI_OSS, KEY_TOKEN);try {initOssClient(endpoint, bkt, ct, ak, sk, token);} catch (Exception e) {ExceptionUtils.rethrow(e);}}
init则是通过environment获取相关属性，然后执行initOssClient
小结
DFsService接口定义了store、download、fetchFileMeta、cleanExpiredFiles方法；AbstractDFsService声明实现DFsService、ApplicationContextAware、DisposableBean接口，它在setApplicationContext方法执行了init；AliOssService继承了AbstractDFsService，通过ossClient实现了store、download、fetchFileMeta方法。
