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# coding: utf-8
# -------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for
# license information.
# --------------------------------------------------------------------------
"""
FILE: sample_conditional_update_async.py
DESCRIPTION:
These samples demonstrate how to update Tables storage table conditionally. The way to update Tables cosmos table is similar.
USAGE:
python sample_conditional_update_async.py
Set the environment variables with your own values before running the sample:
1) TABLES_STORAGE_ENDPOINT_SUFFIX - the Table storage service account URL suffix
2) TABLES_STORAGE_ACCOUNT_NAME - the Tables storage account name
3) TABLES_PRIMARY_STORAGE_ACCOUNT_KEY - the Tables storage account access key
"""
import asyncio
import os
from datetime import datetime
from dotenv import find_dotenv, load_dotenv
from uuid import uuid4
from azure.data.tables.aio import TableClient
from azure.data.tables._models import UpdateMode
from azure.core import MatchConditions
from azure.core.exceptions import ResourceExistsError, ResourceModifiedError
class ConditionalUpdateSamples(object):
def __init__(self):
load_dotenv(find_dotenv())
self.access_key = os.getenv("TABLES_PRIMARY_STORAGE_ACCOUNT_KEY")
self.endpoint_suffix = os.getenv("TABLES_STORAGE_ENDPOINT_SUFFIX")
self.account_name = os.getenv("TABLES_STORAGE_ACCOUNT_NAME")
self.endpoint = "{}.table.{}".format(self.account_name, self.endpoint_suffix)
self.connection_string = (
"DefaultEndpointsProtocol=https;AccountName={};AccountKey={};EndpointSuffix={}".format(
self.account_name, self.access_key, self.endpoint_suffix
)
)
self.table_name_prefix = "SampleConditionalUpdate"
self.entity1 = {
"PartitionKey": "color",
"RowKey": "brand",
"text": "Marker",
"color": "Purple",
"price": 4.99,
"last_updated": datetime.today(),
"product_id": uuid4()
}
self.entity2 = {
"PartitionKey": "color",
"RowKey": "brand",
"color": "Red",
"inventory_count": 42,
"barcode": b"135aefg8oj0ld58" # cspell:disable-line
}
async def conditional_update_basic(self):
async with TableClient.from_connection_string(self.connection_string, self.table_name_prefix + uuid4().hex) as table_client:
await table_client.create_table()
metadata1 = await table_client.create_entity(entity=self.entity1)
print("Entity:")
print(self.entity1)
# Merge properties of an entity with one that already existed in a table.
# This operation will only succeed if the entity has not been modified since we last retrieved the Etag.
try:
metadata2 = await table_client.update_entity(entity=self.entity2, mode=UpdateMode.MERGE, match_condition=MatchConditions.IfNotModified, etag=metadata1["etag"])
except ResourceModifiedError:
print("This entity has been altered and may no longer be in the expected state.")
entity2 = await table_client.get_entity(partition_key=self.entity1["PartitionKey"], row_key=self.entity1["RowKey"])
print("Entity after merge:")
print(entity2)
# Update an existing entity by replacing all of its properties with those specified.
# This operation will only succeed if the entity has not been modified since we last retrieved the Etag.
try:
table_client.update_entity(entity=self.entity2, mode=UpdateMode.REPLACE, match_condition=MatchConditions.IfNotModified, etag=metadata2["etag"])
except ResourceModifiedError:
print("This entity has been altered and may no longer be in the expected state.")
entity3 = await table_client.get_entity(partition_key=self.entity1["PartitionKey"], row_key=self.entity1["RowKey"])
print("Entity after replace:")
print(entity3)
await table_client.delete_table()
async def conditional_update_with_a_target_field(self):
async with TableClient.from_connection_string(self.connection_string, self.table_name_prefix + uuid4().hex) as table_client:
await table_client.create_table()
await table_client.create_entity(entity=self.entity1)
target_field = "barcode"
# In this scenario, will try to create an entity at first. If the entity with the same PartitionKey and RowKey already exists,
# will update the existing entity when target field is missing.
try:
await table_client.create_entity(entity=self.entity2)
except ResourceExistsError:
entity = await table_client.get_entity(partition_key=self.entity2["PartitionKey"], row_key=self.entity2["RowKey"])
if target_field not in entity:
await table_client.update_entity(
entity={"PartitionKey": self.entity2["PartitionKey"], "RowKey": self.entity2["RowKey"], target_field: "foo"},
mode=UpdateMode.MERGE,
match_condition=MatchConditions.IfNotModified,
etag=entity.metadata["etag"]
)
await table_client.delete_table()
async def main():
sample = ConditionalUpdateSamples()
await sample.conditional_update_basic()
await sample.conditional_update_with_a_target_field()
if __name__ == "__main__":
asyncio.run(main())
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