This repository was archived by the owner on Mar 17, 2020. It is now read-only.
forked from GoogleCloudPlatform/python-docs-samples
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathmain.py
More file actions
123 lines (104 loc) · 4.35 KB
/
Copy pathmain.py
File metadata and controls
123 lines (104 loc) · 4.35 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
#!/usr/bin/env python
# Copyright 2016 Google Inc.
#
# Licensed 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.
"""Demonstrates how to connect to Cloud Bigtable and run some basic operations.
Prerequisites:
- Create a Cloud Bigtable cluster.
https://cloud.google.com/bigtable/docs/creating-cluster
- Set your Google Application Default Credentials.
https://developers.google.com/identity/protocols/application-default-credentials
"""
import argparse
import datetime
from google.cloud import bigtable
from google.cloud.bigtable import column_family
from google.cloud.bigtable import row_filters
def main(project_id, instance_id, table_id):
# [START connecting_to_bigtable]
# The client must be created with admin=True because it will create a
# table.
client = bigtable.Client(project=project_id, admin=True)
instance = client.instance(instance_id)
# [END connecting_to_bigtable]
# [START creating_a_table]
print('Creating the {} table.'.format(table_id))
table = instance.table(table_id)
print('Creating column family cf1 with Max Version GC rule...')
# Create a column family with GC policy : most recent N versions
# Define the GC policy to retain only the most recent 2 versions
max_versions_rule = column_family.MaxVersionsGCRule(2)
column_family_id = 'cf1'
column_families = {column_family_id: max_versions_rule}
if not table.exists():
table.create(column_families=column_families)
else:
print("Table {} already exists.".format(table_id))
# [END creating_a_table]
# [START writing_rows]
print('Writing some greetings to the table.')
greetings = ['Hello World!', 'Hello Cloud Bigtable!', 'Hello Python!']
rows = []
column = 'greeting'.encode()
for i, value in enumerate(greetings):
# Note: This example uses sequential numeric IDs for simplicity,
# but this can result in poor performance in a production
# application. Since rows are stored in sorted order by key,
# sequential keys can result in poor distribution of operations
# across nodes.
#
# For more information about how to design a Bigtable schema for
# the best performance, see the documentation:
#
# https://cloud.google.com/bigtable/docs/schema-design
row_key = 'greeting{}'.format(i).encode()
row = table.row(row_key)
row.set_cell(column_family_id,
column,
value,
timestamp=datetime.datetime.utcnow())
rows.append(row)
table.mutate_rows(rows)
# [END writing_rows]
# [START getting_a_row]
print('Getting a single greeting by row key.')
key = 'greeting0'.encode()
# Only retrieve the most recent version of the cell.
row_filter = row_filters.CellsColumnLimitFilter(1)
row = table.read_row(key, row_filter)
print(row.cell_value(column_family_id, column))
# [END getting_a_row]
# [START scanning_all_rows]
print('Scanning for all greetings:')
partial_rows = table.read_rows(filter_=row_filter)
for row in partial_rows:
cell = row.cells[column_family_id][column][0]
print(cell.value.decode('utf-8'))
# [END scanning_all_rows]
# [START deleting_a_table]
print('Deleting the {} table.'.format(table_id))
table.delete()
# [END deleting_a_table]
if __name__ == '__main__':
parser = argparse.ArgumentParser(
description=__doc__,
formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument('project_id', help='Your Cloud Platform project ID.')
parser.add_argument(
'instance_id', help='ID of the Cloud Bigtable instance to connect to.')
parser.add_argument(
'--table',
help='Table to create and destroy.',
default='Hello-Bigtable')
args = parser.parse_args()
main(args.project_id, args.instance_id, args.table)