hbase/examples/thrift/DemoClient.py

#!/usr/bin/python
 
  Licensed to the Apache Software Foundation (ASF) under one
  or more contributor license agreements.  See the NOTICE file
  distributed with this work for additional information
  regarding copyright ownership.  The ASF licenses this file
  to you under the Apache License, Version 2.0 (the
  "License"); you may not use this file except in compliance
  with the License.  You may obtain a copy of the License at
 
     http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
''' 
# Instructions:
# 1. Run Thrift to generate the python module HBase
#    thrift --gen py ../../../src/main/resources/org/apache/hadoop/hbase/thrift/Hbase.thrift
# 2. Create a directory of your choosing that contains:
#     a. This file (DemoClient.py).
#     b. The directory gen-py/hbase (generated by instruction step 1).
#     c. The directory {$THRIFT_HOME}/lib/py/build/lib.{YOUR_SYSTEM}/thrift.
#    Or, modify the import statements below such that this file can access the 
#    directories from steps 3b and 3c.
# 3. Execute {python DemoClient.py}.

import sys
import time

from thrift import Thrift
from thrift.transport import TSocket, TTransport
from thrift.protocol import TBinaryProtocol
from hbase import ttypes
from hbase.Hbase import Client, ColumnDescriptor, Mutation

def printVersions(row, versions):
  print "row: " + row + ", values: ",
  for cell in versions:
    print cell.value + "; ",
  print

def printRow(entry):
  print "row: " + entry.row + ", cols:",
  for k in sorted(entry.columns):
    print k + " => " + entry.columns[k].value,
  print

# Make socket
transport = TSocket.TSocket('localhost', 9090)

# Buffering is critical. Raw sockets are very slow
transport = TTransport.TBufferedTransport(transport)

# Wrap in a protocol
protocol = TBinaryProtocol.TBinaryProtocol(transport)

# Create a client to use the protocol encoder
client = Client(protocol)

# Connect!
transport.open()

t = "demo_table"

#
# Scan all tables, look for the demo table and delete it.
#
print "scanning tables..."
for table in client.getTableNames():
  print "  found: %s" %(table)
  if table == t:
    if client.isTableEnabled(table):
      print "    disabling table: %s"  %(t)
      client.disableTable(table)
    print "    deleting table: %s"  %(t)
    client.deleteTable(table)

columns = []
col = ColumnDescriptor()
col.name = 'entry:'
col.maxVersions = 10
columns.append(col)
col = ColumnDescriptor()
col.name = 'unused:'
columns.append(col)

try:
  print "creating table: %s" %(t)
  client.createTable(t, columns)
except AlreadyExists, ae:
  print "WARN: " + ae.message

cols = client.getColumnDescriptors(t)
print "column families in %s" %(t)
for col_name in cols.keys():
  col = cols[col_name]
  print "  column: %s, maxVer: %d" % (col.name, col.maxVersions)
#
# Test UTF-8 handling
#
invalid = "foo-\xfc\xa1\xa1\xa1\xa1\xa1"
valid = "foo-\xE7\x94\x9F\xE3\x83\x93\xE3\x83\xBC\xE3\x83\xAB";

# non-utf8 is fine for data
mutations = [Mutation(column="entry:foo",value=invalid)]
print str(mutations)
client.mutateRow(t, "foo", mutations)

# try empty strings
mutations = [Mutation(column="entry:", value="")]
client.mutateRow(t, "", mutations)

# this row name is valid utf8
mutations = [Mutation(column="entry:foo", value=valid)]
client.mutateRow(t, valid, mutations)

# non-utf8 is not allowed in row names
try:
  mutations = [Mutation(column="entry:foo", value=invalid)]
  client.mutateRow(t, invalid, mutations)
except ttypes.IOError, e:
  print 'expected exception: %s' %(e.message)

# Run a scanner on the rows we just created
print "Starting scanner..."
scanner = client.scannerOpen(t, "", ["entry:"])

r = client.scannerGet(scanner)
while r:
  printRow(r[0])
  r = client.scannerGet(scanner)
print "Scanner finished"

#
# Run some operations on a bunch of rows.
#
for e in range(100, 0, -1):
    # format row keys as "00000" to "00100"
  row = "%0.5d" % (e)

  mutations = [Mutation(column="unused:", value="DELETE_ME")]
  client.mutateRow(t, row, mutations)
  printRow(client.getRow(t, row)[0])
  client.deleteAllRow(t, row)

  mutations = [Mutation(column="entry:num", value="0"),
               Mutation(column="entry:foo", value="FOO")]
  client.mutateRow(t, row, mutations)
  printRow(client.getRow(t, row)[0]);

  mutations = [Mutation(column="entry:foo",isDelete=True),
               Mutation(column="entry:num",value="-1")]
  client.mutateRow(t, row, mutations)
  printRow(client.getRow(t, row)[0])

  mutations = [Mutation(column="entry:num", value=str(e)),
               Mutation(column="entry:sqr", value=str(e*e))]
  client.mutateRow(t, row, mutations)
  printRow(client.getRow(t, row)[0])

  time.sleep(0.05)

  mutations = [Mutation(column="entry:num",value="-999"),
               Mutation(column="entry:sqr",isDelete=True)]
  client.mutateRowTs(t, row, mutations, 1) # shouldn't override latest
  printRow(client.getRow(t, row)[0])

  versions = client.getVer(t, row, "entry:num", 10)
  printVersions(row, versions)
  if len(versions) != 4:
    print("FATAL: wrong # of versions")
    sys.exit(-1)

  r = client.get(t, row, "entry:foo")
  if not r:
    print "yup, we didn't find entry:foo"
  # just to be explicit, we get lists back, if it's empty there was no matching row.
  if len(r) > 0:
    raise "shouldn't get here!"

columnNames = []
for (col, desc) in client.getColumnDescriptors(t).items():
  print "column with name: "+desc.name
  print desc
  columnNames.append(desc.name+":")

print "Starting scanner..."
scanner = client.scannerOpenWithStop(t, "00020", "00040", columnNames)

r = client.scannerGet(scanner)
while r:
  printRow(r[0])
  r = client.scannerGet(scanner)

client.scannerClose(scanner)
print "Scanner finished"

transport.close()