GitHub - canimus/aiowebhdfs: A modern and async implementation of the WebHDFS API in python

2 min read Original article ↗

aiowebhdfs

I know, nobody uses Hadoop anymore, but for those who do, here is a library that handles large files with async features for web requests using the httpx library and aiofiles for streaming data from HDFS

Features

  • Implements retries and timeout windows with retry_async from opnieuw library
  • Implements streaming through the aiofiles library
  • Implments async requests through the httpx library
  • Fully tested for core subset of operations in WebHDFS v3.2.1

CREATE = Write File

from aiowebhdfs import WebHdfsAsyncClient
client = WebHdfsAsyncClient(host='namenode.local', port=8443, user='spark', kerberos_token=token)
await client.create('c:\\temp\\bigfile.txt', '/data/agg/bigfile.txt', overwrite=False)

OPEN = Read File

from aiowebhdfs import WebHdfsAsyncClient
client = WebHdfsAsyncClient(host='namenode.local', port=8443, user='spark', kerberos_token=token)
await client.open('/data/agg/bigfile.txt')
Content of the file

GETFILESTATUS = File Info

from aiowebhdfs import WebHdfsAsyncClient
client = WebHdfsAsyncClient(host='namenode.local', port=8443, user='spark', kerberos_token=token)
await client.get_file_status('/data/agg/bigfile.txt')
{
  "FileStatus":
  {
    "accessTime"      : 0,
    "blockSize"       : 0,
    "group"           : "supergroup",
    "length"          : 0,             //in bytes, zero for directories
    "modificationTime": 1320173277227,
    "owner"           : "webuser",
    "pathSuffix"      : "",
    "permission"      : "777",
    "replication"     : 0,
    "type"            : "DIRECTORY"    //enum {FILE, DIRECTORY}
  }
}

LISTSTATUS = List Directory

from aiowebhdfs import WebHdfsAsyncClient
client = WebHdfsAsyncClient(host='namenode.local', port=8443, user='spark', kerberos_token=token)
await client.list_directory('/tmp')
{
  "FileStatuses":
  {
    "FileStatus":
    [
      {
        "accessTime"      : 1320171722771,
        "blockSize"       : 33554432,
        "group"           : "supergroup",
        "length"          : 24930,
        "modificationTime": 1320171722771,
        "owner"           : "webuser",
        "pathSuffix"      : "a.patch",
        "permission"      : "644",
        "replication"     : 1,
        "type"            : "FILE"
      },
      {
        "accessTime"      : 0,
        "blockSize"       : 0,
        "group"           : "supergroup",
        "length"          : 0,
        "modificationTime": 1320895981256,
        "owner"           : "szetszwo",
        "pathSuffix"      : "bar",
        "permission"      : "711",
        "replication"     : 0,
        "type"            : "DIRECTORY"
      },
      ...
    ]
  }
}

GETCONTENTSUMMARY = Summary of Directory

from aiowebhdfs import WebHdfsAsyncClient
client = WebHdfsAsyncClient(host='namenode.local', port=8443, user='spark', kerberos_token=token)
await client.list_directory('/tmp')
{
  "FileStatuses":
  {
    "FileStatus":
    [
      {
        "accessTime"      : 1320171722771,
        "blockSize"       : 33554432,
        "group"           : "supergroup",
        "length"          : 24930,
        "modificationTime": 1320171722771,
        "owner"           : "webuser",
        "pathSuffix"      : "a.patch",
        "permission"      : "644",
        "replication"     : 1,
        "type"            : "FILE"
      },
      {
        "accessTime"      : 0,
        "blockSize"       : 0,
        "group"           : "supergroup",
        "length"          : 0,
        "modificationTime": 1320895981256,
        "owner"           : "szetszwo",
        "pathSuffix"      : "bar",
        "permission"      : "711",
        "replication"     : 0,
        "type"            : "DIRECTORY"
      },
      ...
    ]
  }
}