Spark iterate HDFS directory

Question

I have a directory of directories on HDFS, and I want to iterate over the directories. Is there any easy way to do this with Spark using the SparkContext object?

Solution 1

You can use org.apache.hadoop.fs.FileSystem. Specifically, FileSystem.listFiles([path], true)

And with Spark...

FileSystem.get(sc.hadoopConfiguration).listFiles(..., true)

Edit

It's worth noting that good practice is to get the FileSystem that is associated with the Path's scheme.

path.getFileSystem(sc.hadoopConfiguration).listFiles(path, true)

Solution 2

Here's PySpark version if someone is interested:

    hadoop = sc._jvm.org.apache.hadoop

    fs = hadoop.fs.FileSystem
    conf = hadoop.conf.Configuration() 
    path = hadoop.fs.Path('/hivewarehouse/disc_mrt.db/unified_fact/')

    for f in fs.get(conf).listStatus(path):
        print(f.getPath(), f.getLen())

In this particular case I get list of all files that make up disc_mrt.unified_fact Hive table.

Other methods of FileStatus object, like getLen() to get file size are described here:

Class FileStatus

Solution 3

import  org.apache.hadoop.fs.{FileSystem,Path}

FileSystem.get( sc.hadoopConfiguration ).listStatus( new Path("hdfs:///tmp")).foreach( x => println(x.getPath ))

This worked for me.

Spark version 1.5.0-cdh5.5.2

Solution 4

this did the job for me

FileSystem.get(new URI("hdfs://HAservice:9000"), sc.hadoopConfiguration).listStatus( new Path("/tmp/")).foreach( x => println(x.getPath ))

Solution 5

@Tagar didn't say how to connect remote hdfs, but this answer did:

URI           = sc._gateway.jvm.java.net.URI
Path          = sc._gateway.jvm.org.apache.hadoop.fs.Path
FileSystem    = sc._gateway.jvm.org.apache.hadoop.fs.FileSystem
Configuration = sc._gateway.jvm.org.apache.hadoop.conf.Configuration


fs = FileSystem.get(URI("hdfs://somehost:8020"), Configuration())

status = fs.listStatus(Path('/some_dir/yet_another_one_dir/'))

for fileStatus in status:
    print(fileStatus.getPath())

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Comments

[JimLohse]

really nice! I had this question, granted, I guess this wouldn't work in the original spark-submit call

[horatio1701d]

How can I create a list of the files using the RemoteIterator this creates?

[Shrinivas Deshmukh]

an upvote for pyspark version! worked perfectly! thanks!

[ASH]

This worked fine for me, for a single folder. Is there some way to get this to run at the level of the parent folder, and get all files in all subfolders? That would be VERY helpful/useful for me.

[Denis Ka]

thank U! was wondering how to make it in python