Flowfile 绝对路径 Nifi

问题描述

我正在尝试使用批量加载选项将流文件加载到 MySQL 数据库中.下面是我在 UpdateAttribute 处理器中使用的查询，并在更新参数以执行批量加载后将该查询传递给 PutSQL.

LOAD DATA INFILE '${absolute.path}${filename}' INTO TABLE ${dest.database}.${db.table.name} FIELDS TERMINATED BY ', LINES TERMINATED BY '\n'

当我运行流程时，它没有说文件未找到异常.

这里 MySQL 服务器和 Nifi 在不同的节点上，所以我不能使用 LOAD DATA LOCAL INFILE 查询.

即使我在 SQL 查询中提到了流文件的完整绝对路径，我也不知道为什么会出现文件未找到异常.

当我使用带有硬编码文件名的查询并在 nifi 节点中提供文件的绝对路径时，它按预期工作.

工作:

LOAD DATA LOCAL INFILE '/path/in/nifi/node/to/file/data.csv' INTO TABLE ${dest.database}.${db.table.name} FIELDS TERMINATED BY ',' 以 '\n'} 结尾的行

问题是如何获取流文件的绝对路径并将相同的流文件加载到mysql中.

流程:

• 停止 PutSQL 处理器并让流文件排队.
• 一旦他们排队，右键单击success关系
  UpdateAttribute 和 PutSQL 之间并选择 List Queue.
• 选择任意一个流文件并导航到 Attributes 选项卡并查看如果属性absolute.path 和flowfilename 存在并且如果
  它们确实存在，请验证它们是否具有预期值集.在你的情况下 absolute.path 应该有值 /path/in/nifi/node/to/file 和 flowfilename 应该有值 <代码>/data.csv

问题:您是否使用 UpdateAttribute 自己设置这些属性，原因是，NiFi 不会生成名为 flowfilename 的属性，而是生成名为 <代码>文件名.

还有一点，请确保 absolute.path 的值以 / 结尾或 flowfilename 的值开始带有 /.如果没有，它们将被附加，结果将是 /path/in/nifi/node/to/filedata.csv.您可以尝试@Mahendra 建议的 append 函数，否则您可以简单地使用 ${absolute.path}/${flowfilename}.

更新

我刚刚意识到absolute.path 是一个核心属性，如filename、filesize、mime.type等.有些处理器使用所有核心属性，而有些处理器使用很少的必要属性.GenerateTableFetch 写入 absolute.path 但没有为它设置任何东西.这就是为什么它有 ./ 这是默认值.

所以我对您的工作方法的建议是，您可以使用 UpdateAttribute 手动设置/覆盖 absolute.path 属性(就像您覆盖了 filename) 并设置所需的值，即 /path/in/nifi/node/to/file

I'm trying to load the flow files into MySQL database using bulk load option. Below is the query I'm using as part of the UpdateAttribute processor and passing that query to PutSQL after updating the parameters to do bulk load.

LOAD DATA INFILE '${absolute.path}${filename}' INTO TABLE ${dest.database}.${db.table.name} FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n'

When I ran the flow it's failing saying file not found exception.

. There were a total of 1 FlowFiles that failed, 0 that succeeded, and 0 that were not execute and will be routed to retry; : java.sql.BatchUpdateException: Unable to open file 'data.csv'for 'LOAD DATA INFILE command.Due to underlying IOException:`

** BEGIN NESTED EXCEPTION ** 

java.io.FileNotFoundException
MESSAGE: data.csv (No such file or directory)
java.io.FileNotFoundException: data.csv (No such file or directory).

Here MySQL Server and Nifi are on different nodes so I can't use LOAD DATA LOCAL INFILE query.

I'm not sure why I'm getting file not found exception even though I mentioned the complete absolute path of the flow file in the SQL Query.

When I use query with hard coded file name and providing the absolute path of the file in nifi node, it's working as expected.

Working:

LOAD DATA LOCAL INFILE '/path/in/nifi/node/to/file/data.csv' INTO TABLE ${dest.database}.${db.table.name} FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n'}

Question is how to get the absolute path of the flow file and load the same flow file into mysql.

Flow:

• Stop the PutSQL processor and let the flowfiles queue up.
• Once they are queued up, right click on the success relationship
  between UpdateAttribute and PutSQL and select List Queue.
• Select any one flowfile and navigate to the Attributes tab and see if the attributes absolute.path and flowfilename exists and if
  they do exist, verify if they have the expected value set. In your case absolute.path should have the value /path/in/nifi/node/to/file and flowfilename should have the value /data.csv

Question for you: Are you setting these attributes yourself using UpdateAttribute, reason is, NiFi doesn't generate an attribute named flowfilename, it generates one with the name filename.

One more thing, make sure either the value for absolute.path ends with a / in the end or the value of flowfilename begins with a /. If not, they will be appended and the result will be /path/in/nifi/node/to/filedata.csv. You can try the append function that @Mahendra suggested, else you can simply use ${absolute.path}/${flowfilename}.

Update

I just realized that absolute.path is a core attribute like filename, filesize, mime.type, etc. Some processors use all the core attributes while some use very few which are needed. GenerateTableFetch writes absolute.path but doesn't set anything for it. That's why it has ./ which is the default value.

So my suggestion for your approach to work is, you can manually set/overwrite absolute.path attribute using UpdateAttribute (just like you have overwritten filename) and set the desired value which is /path/in/nifi/node/to/file

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