持久化 h2o mojo 时出错（版本 3.20.0.1）答案

【问题标题】：error while persisting h2o mojo (version 3.20.0.1)持久化 h2o mojo 时出错（版本 3.20.0.1）
【发布时间】：2018-06-20 04:41:56
【问题描述】：

我在最新的 h2o 版本中持续存在 mojos 的问题。该代码在旧版本（3.10）上运行良好

这是一个示例代码和正在抛出的异常。

   public static Schema[] getAllSchemas() {
        ServiceLoader<Schema> schemaLoader = 
        ServiceLoader.load(Schema.class);
        List<Schema> allSchemas = new ArrayList<>();
        for (Schema schema : schemaLoader) {
            allSchemas.add(schema);
        }
        return allSchemas.toArray(new Schema[allSchemas.size()]);
   }

   public static byte[] extractIce(Model model) throws IOException {
       final UUID uuid = UUID.randomUUID();
       String tempFile = "/tmp/" + uuid;
       model.exportMojo(tempFile, true);
       final byte[] bytes = IOUtils.toByteArray(new 
                                   FileInputStream(tempFile)); 
       return bytes; 
    }


   public static void main (String []args) {
      H2OApp.main();
      SchemaServer.registerAllSchemasIfNecessary(getAllSchemas());
      // get the model that needs to be persisted
      // Model model = getH2OModel();
      byte[] extractIce(model);
   }

这是被抛出的异常。

Caused by: java.lang.IllegalArgumentException: Cannot find Builder for algo url name drf
   at hex.ModelBuilder.ensureBuilderIndex(ModelBuilder.java:141) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]
   at hex.ModelBuilder.havePojo(ModelBuilder.java:120) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]
   at hex.Model.havePojo(Model.java:118) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]
   at water.api.schemas3.ModelSchemaV3.fillFromImpl(ModelSchemaV3.java:73) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]
   at water.api.schemas3.ModelSchemaV3.fillFromImpl(ModelSchemaV3.java:21) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]
   at hex.ModelMojoWriter.writeModelDetails(ModelMojoWriter.java:277) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]
   at hex.ModelMojoWriter.writeTo(ModelMojoWriter.java:178) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]
   at hex.ModelMojoWriter.writeTo(ModelMojoWriter.java:169) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]
   at hex.ModelMojoWriter.writeTo(ModelMojoWriter.java:161) ~[xyz-platform-all-7.9.0-SNAPSHOT.jar:7.9.0-SNAPSHOT]

【问题讨论】：

标签： h2o

【解决方案1】：

以防万一有人遇到同样的问题。在 H2OApp 启动后，我可以通过调用以下方法 (registerSchemasAndAlgos) 来保持 mojos。

import hex.api.RegisterAlgos;
import water.api.RequestServer;
import water.api.Schema;
import water.api.SchemaServer;
import java.util.ArrayList;
import java.util.List;
import java.util.ServiceLoader;

public void registerSchemasAndAlgos() {
    // schemas
    SchemaServer.registerAllSchemasIfNecessary(getAllSchemas());

    // algos
    RegisterAlgos algos = new RegisterAlgos();
    algos.registerEndPoints(new RequestServer.DummyRestApiContext());
}

public void registerAlgos() {
    RegisterAlgos algos = new RegisterAlgos();
    algos.registerEndPoints(new RequestServer.DummyRestApiContext());
}

public Schema[] getAllSchemas() {
    ServiceLoader<Schema> schemaLoader = ServiceLoader.load(Schema.class);
    List<Schema> allSchemas = new ArrayList<>();
    for (Schema schema : schemaLoader) {
        allSchemas.add(schema);
    }
    return allSchemas.toArray(new Schema[allSchemas.size()]);
}

【讨论】：