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本文主要研究一下PowerJob的AliOssService
DFsService
tech/powerjob/server/extension/dfs/DFsService.java
代码语言：javascript复制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
代码语言：javascript复制@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);
}
@Override
public 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
代码语言：javascript复制@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
代码语言：javascript复制 @Override
public 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
代码语言：javascript复制 @Override
public 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
代码语言：javascript复制 @Override
public 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
代码语言：javascript复制 @Override
public 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
代码语言：javascript复制 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。
