webhdfs - A client library implementation for Hadoop WebHDFS, and HttpFs, for Ruby
The webhdfs gem is to access Hadoop WebHDFS (EXPERIMENTAL: and HttpFs). WebHDFS::Client is a client class, and WebHDFS::FileUtils is utility like 'fileutils'.
Installation
gem install webhdfs
Usage
WebHDFS::Client
For client object interface:
require 'webhdfs'
client = WebHDFS::Client.new(hostname, port)
# or with pseudo username authentication
client = WebHDFS::Client.new(hostname, port, username)
To create/append/read files:
client.create('/path/to/file', data)
client.create('/path/to/file', data, :overwrite => false, :blocksize => 268435456, :replication => 5, :permission => '0666')
#This does not require whole data in memory, and it can be read chunk by chunk, ex: File data
client.create('/path/to/file', file_IO_handle, :overwrite => false, :permission => 0666)
client.append('/path/to/existing/file', data)
client.read('/path/to/target') #=> data
client.read('/path/to/target' :offset => 2048, :length => 1024) #=> data
To mkdir/rename/delete directories or files:
client.mkdir('/hdfs/dirname')
client.mkdir('/hdfs/dirname', :permission => '0777')
client.rename(original_path, dst_path)
client.delete(path)
client.delete(dir_path, :recursive => true)
To get status or list of files and directories:
client.stat(file_path) #=> key-value pairs for file status
client.list(dir_path) #=> list of key-value pairs for files in dir_path
And, 'content_summary', 'checksum', 'homedir', 'chmod', 'chown', 'replication' and 'touch' methods available.
For known errors, automated retries are available. Set retry_known_errors option as true.
#### To retry for LeaseExpiredException automatically
client.retry_known_errors = true
# client.retry_interval = 1 # [sec], default: 1
# client.retry_times = 1 # [times], default: 1
WebHDFS::FileUtils
require 'webhdfs/fileutils'
WebHDFS::FileUtils.set_server(host, port)
# or
WebHDFS::FileUtils.set_server(host, port, username, doas)
WebHDFS::FileUtils.copy_from_local(localpath, hdfspath)
WebHDFS::FileUtils.copy_to_local(hdfspath, localpath)
WebHDFS::FileUtils.append(path, data)
For HttpFs
For HttpFs instead of WebHDFS:
client = WebHDFS::Client.new('hostname', 14000)
client.httpfs_mode = true
client.read(path) #=> data
# or with webhdfs/filetuils
WebHDFS::FileUtils.set_server('hostname', 14000)
WebHDFS::FileUtils.set_httpfs_mode
WebHDFS::FileUtils.copy_to_local(remote_path, local_path)
For HTTP Proxy servers
client = WebHDFS::Client.new('hostname', 14000, 'proxy.server.local', 8080)
client.proxy_user = 'jack' # if needed
client.proxy_pass = 'secret' # if needed
For SSL
Note that net/https and openssl libraries must be available:
client = WebHDFS::Client.new('hostname', 4443)
client.ssl = true
client.ssl_ca_file = "/path/to/ca_file.pem" # if needed
client.ssl_varify_mode = :peer # if needed (:none or :peer)
client.ssl_version = :TLSv1 # if needed
For Kerberos Authentication
Note that gssapi library must be available:
client = WebHDFS::Client.new('hostname', 14000)
# or if you want to use client delegation token with renewing per 8 hours
client = WebHDFS::Client.new('hostname', 14000, username, nil, nil, nil, {}, 8)
client.kerberos = true
client.kerberos_keytab = "/path/to/project.keytab"
For SSL Client Authentication
Note that openssl libraries must be available:
require 'openssl'
client = WebHDFS::Client.new(host, port)
client.ssl = true
client.ssl_key = OpenSSL::PKey::RSA.new(open('/path/to/key.pem'))
client.ssl_cert = OpenSSL::X509::Certificate.new(open('/path/to/cert.pem'))
AUTHORS
- Kazuki Ohta [email protected]
- TAGOMORI Satoshi [email protected]
LICENSE
- Copyright: Copyright (c) 2012- Fluentd Project
- License: Apache License, Version 2.0
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