Question

我需要创建AVRO文件，但为此我需要两件事：

1）JSON

2）Avro Schema

根据这两个要求 - 我有JSON：

{"web-app": {
  "servlet": [   
    {
      "servlet-name": "cofaxCDS",
      "servlet-class": "org.cofax.cds.CDSServlet",
      "init-param": {
        "configGlossary:installationAt": "Philadelphia, PA",
        "configGlossary:adminEmail": "ksm@pobox.com",
        "configGlossary:poweredBy": "Cofax",
        "configGlossary:poweredByIcon": "/images/cofax.gif",
        "configGlossary:staticPath": "/content/static",
        "templateProcessorClass": "org.cofax.WysiwygTemplate",
        "templateLoaderClass": "org.cofax.FilesTemplateLoader",
        "templatePath": "templates",
        "templateOverridePath": "",
        "defaultListTemplate": "listTemplate.htm",
        "defaultFileTemplate": "articleTemplate.htm",
        "useJSP": false,
        "jspListTemplate": "listTemplate.jsp",
        "jspFileTemplate": "articleTemplate.jsp",
        "cachePackageTagsTrack": 200,
        "cachePackageTagsStore": 200,
        "cachePackageTagsRefresh": 60,
        "cacheTemplatesTrack": 100,
        "cacheTemplatesStore": 50,
        "cacheTemplatesRefresh": 15,
        "cachePagesTrack": 200,
        "cachePagesStore": 100,
        "cachePagesRefresh": 10,
        "cachePagesDirtyRead": 10,
        "searchEngineListTemplate": "forSearchEnginesList.htm",
        "searchEngineFileTemplate": "forSearchEngines.htm",
        "searchEngineRobotsDb": "WEB-INF/robots.db",
        "useDataStore": true,
        "dataStoreClass": "org.cofax.SqlDataStore",
        "redirectionClass": "org.cofax.SqlRedirection",
        "dataStoreName": "cofax",
        "dataStoreDriver": "com.microsoft.jdbc.sqlserver.SQLServerDriver",
        "dataStoreUrl": "jdbc:microsoft:sqlserver://LOCALHOST:1433;DatabaseName=goon",
        "dataStoreUser": "sa",
        "dataStorePassword": "dataStoreTestQuery",
        "dataStoreTestQuery": "SET NOCOUNT ON;select test='test';",
        "dataStoreLogFile": "/usr/local/tomcat/logs/datastore.log",
        "dataStoreInitConns": 10,
        "dataStoreMaxConns": 100,
        "dataStoreConnUsageLimit": 100,
        "dataStoreLogLevel": "debug",
        "maxUrlLength": 500}},
    {
      "servlet-name": "cofaxEmail",
      "servlet-class": "org.cofax.cds.EmailServlet",
      "init-param": {
      "mailHost": "mail1",
      "mailHostOverride": "mail2"}},
    {
      "servlet-name": "cofaxAdmin",
      "servlet-class": "org.cofax.cds.AdminServlet"},

    {
      "servlet-name": "fileServlet",
      "servlet-class": "org.cofax.cds.FileServlet"},
    {
      "servlet-name": "cofaxTools",
      "servlet-class": "org.cofax.cms.CofaxToolsServlet",
      "init-param": {
        "templatePath": "toolstemplates/",
        "log": 1,
        "logLocation": "/usr/local/tomcat/logs/CofaxTools.log",
        "logMaxSize": "",
        "dataLog": 1,
        "dataLogLocation": "/usr/local/tomcat/logs/dataLog.log",
        "dataLogMaxSize": "",
        "removePageCache": "/content/admin/remove?cache=pages&id=",
        "removeTemplateCache": "/content/admin/remove?cache=templates&id=",
        "fileTransferFolder": "/usr/local/tomcat/webapps/content/fileTransferFolder",
        "lookInContext": 1,
        "adminGroupID": 4,
        "betaServer": true}}],
  "servlet-mapping": {
    "cofaxCDS": "/",
    "cofaxEmail": "/cofaxutil/aemail/*",
    "cofaxAdmin": "/admin/*",
    "fileServlet": "/static/*",
    "cofaxTools": "/tools/*"},

  "taglib": {
    "taglib-uri": "cofax.tld",
    "taglib-location": "/WEB-INF/tlds/cofax.tld"}}}

但是如何基于它创建AVRO Schema？

寻找编程方式，因为它将有许多模式，并且不能每次手动创建Avro Schema。

我检查了avro-tools-1.8.1.jar＆＃39;但是这不能直接从JSON创建Avro Schema。

寻找可以创建JSON的Jar或Python代码 - ＆gt; Avro架构。如果数据类型不完美就可以了（字符串，整数和浮点数足以开始）。

Answer 1

您可以使用Kite SDK util从json输入中推断出avro架构。

https://github.com/kite-sdk/kite/blob/master/kite-data/kite-data-core/src/main/java/org/kitesdk/data/spi/JsonUtil.java#L539

示例：

    String json = "{\n" +
            "    \"id\": 1,\n" +
            "    \"name\": \"A green door\",\n" +
            "    \"price\": 12.50,\n" +
            "    \"tags\": [\"home\", \"green\"]\n" +
            "}\n"
            ;
    String avroSchema = JsonUtil.inferSchema(JsonUtil.parse(json), "myschema").toString();
    System.out.println(avroSchema);

结果：

{  
   "type":"record",
   "name":"myschema",
   "fields":[  
      {  
         "name":"id",
         "type":"int",
         "doc":"Type inferred from '1'"
      },
      {  
         "name":"name",
         "type":"string",
         "doc":"Type inferred from '\"A green door\"'"
      },
      {  
         "name":"price",
         "type":"double",
         "doc":"Type inferred from '12.5'"
      },
      {  
         "name":"tags",
         "type":{  
            "type":"array",
            "items":"string"
         },
         "doc":"Type inferred from '[\"home\",\"green\"]'"
      }
   ]
}

您可以找到maven依赖关系here

Answer 2

如果要避免为每种JSON格式创建专用的AVRO模式，可以使用rec-avro包。

它允许您采用任何python数据结构，包括已解析的XML或JSON，并将其存储在Avro中，而无需专用的架构。

我在python 3上对其进行了测试。

您可以将其安装为pip3 install rec-avro或在https://github.com/bmizhen/rec-avro上查看代码和文档

我在这里将json转换为avro示例代码：https://stackoverflow.com/a/55444481/6654219

Answer 3

这个简单的复制和粘贴avro模式的作品很酷。

https://toolslick.com/generation/metadata/avro-schema-from-json

Answer 4

试一试。 http://www.dataedu.ca/avro

它基本上可以推断出接受JSON的Avro模式。

您甚至可以给它 JSON数组。它将生成与数组中的所有 JSON文档兼容的Avro模式。

还有其他工具可以验证结果。

有没有办法以编程方式将JSON转换为AVRO Schema？

4 个答案: