无法在databricks社区版集群中显示dbfs文件.FileNotFoundError:[错误2]没有这样的文件或目录:

问题描述：

尝试读取 databricks社区版集群中的增量日志文件.(databricks-7.2版)

Trying to read delta log file in databricks community edition cluster. (databricks-7.2 version)

df=spark.range(100).toDF("id")
df.show()
df.repartition(1).write.mode("append").format("delta").save("/user/delta_test")

with open('/user/delta_test/_delta_log/00000000000000000000.json','r')  as f:
  for l in f:
    print(l)

找不到文件错误:

Getting file not found error:

FileNotFoundError: [Errno 2] No such file or directory: '/user/delta_test/_delta_log/00000000000000000000.json'
---------------------------------------------------------------------------
FileNotFoundError                         Traceback (most recent call last)
<command-1759925981994211> in <module>
----> 1 with open('/user/delta_test/_delta_log/00000000000000000000.json','r')  as f:
      2   for l in f:
      3     print(l)

FileNotFoundError: [Errno 2] No such file or directory: '/user/delta_test/_delta_log/00000000000000000000.json'

我尝试添加/dbfs/， dbfs:/都没有结果，仍然出现相同的错误.

I have tried with adding /dbfs/,dbfs:/ nothing got worked out,Still getting same error.

with open('/dbfs/user/delta_test/_delta_log/00000000000000000000.json','r')  as f:
  for l in f:
    print(l)

但是使用 dbutils.fs.head ，我可以读取文件.

But using dbutils.fs.head i was able to read the file.

dbutils.fs.head("/user/delta_test/_delta_log/00000000000000000000.json")

'{"commitInfo":{"timestamp":1598224183331,"userId":"284520831744638","userName":"","operation":"WRITE","operationParameters":{"mode":"Append","partitionBy":"[]"},"notebook":{"","isolationLevel":"WriteSerializable","isBlindAppend":true,"operationMetrics":{"numFiles":"1","numOutputBytes":"1171","numOutputRows":"100"}}}\n{"protocol":{"minReaderVersi...etc

我们如何使用 python打开方法在数据块中读取/捕获 dbfs文件 ?

How can we read/cat a dbfs file in databricks with python open method?

答

默认情况下，此数据位于DBFS上，并且您的代码需要了解如何访问它.Python对此一无所知-这就是它失败的原因.

By default, this data is on the DBFS, and your code need to understand how to access it. Python doesn't know about it - that's why it's failing.

但是有一种解决方法-DBFS安装在/dbfs 的节点上，因此您只需要将DBFS附加到您的文件名:而不是/user/delta_test/_delta_log/00000000000000000000.json ，使用/dbfs/user/delta_test/_delta_log/00000000000000000000.json

But there is a workaround - DBFS is mounted to the nodes at /dbfs, so you just need to append it to your file name: instead of /user/delta_test/_delta_log/00000000000000000000.json, use /dbfs/user/delta_test/_delta_log/00000000000000000000.json

更新:在社区版中，在DBR 7+中，此安装被禁用.解决方法是使用 dbutils.fs.cp 命令将文件从DBFS复制到本地目录，例如/tmp 或/var/tmp ，然后从中读取.

update: on community edition, in DBR 7+, this mount is disabled. The workaround would be to use dbutils.fs.cp command to copy file from DBFS to local directory, like, /tmp, or /var/tmp, and then read from it.

无法在databricks社区版集群中显示dbfs文件.FileNotFoundError:[错误2]没有这样的文件或目录:

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