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# ------------------------------------
# Copyright (c) Microsoft Corporation.
# Licensed under the MIT License.
# ------------------------------------
import os
from typing import Any, MutableMapping, List, cast
import uuid
from azure.identity import DefaultAzureCredential
from azure.core.exceptions import HttpResponseError
from azure.digitaltwins.core import DigitalTwinsClient
# Scenario example of how to:
# - create a DigitalTwins Service Client using the DigitalTwinsClient constructor
# - create digital twin based on a model
# - get digital twin
# - update digital twin using JSON patch
# - delete digital twin
#
# Preconditions:
# - Environment variables have to be set
# - DigitalTwins enabled device must exist on the ADT hub
#
# For the purpose of this example we will create temporary digital twin using random Ids.
# We have to make sure these Ids are unique within the DT instance so we use generated UUIDs.
try:
model_id = 'dtmi:samples:digitaltwinlifecyclemodel;1'
digital_twin_id = 'digitalTwin-' + str(uuid.uuid4())
temporary_model = {
"@id": model_id,
"@type": "Interface",
"@context": "dtmi:dtdl:context;2",
"displayName": "TempModel",
"contents": [
{
"@type": "Property",
"name": "Prop1",
"schema": "double"
}
]
}
temporary_twin = {
"$metadata": {
"$model": model_id
},
"$dtId": digital_twin_id,
"Prop1": 42
}
# DefaultAzureCredential supports different authentication mechanisms and determines
# the appropriate credential type based of the environment it is executing in.
# It attempts to use multiple credential types in an order until it finds a working credential.
# - AZURE_URL: The tenant ID in Azure Active Directory
url = os.getenv("AZURE_URL")
if url is None:
raise ValueError("AZURE_URL environment variable is not set")
# DefaultAzureCredential expects the following three environment variables:
# - AZURE_TENANT_ID: The tenant ID in Azure Active Directory
# - AZURE_CLIENT_ID: The application (client) ID registered in the AAD tenant
# - AZURE_CLIENT_SECRET: The client secret for the registered application
credential = DefaultAzureCredential()
service_client = DigitalTwinsClient(url, credential) # type: ignore
# Create model first from sample dtdl
model = service_client.create_models(cast(List[MutableMapping[str, Any]], [temporary_model]))
print('Created Model:')
print(model)
# Create digital twin based on the created model
created_twin = service_client.upsert_digital_twin(digital_twin_id, temporary_twin)
print('Created Digital Twin:')
print(created_twin)
# Get digital twin
get_twin = service_client.get_digital_twin(digital_twin_id)
print('Get Digital Twin:')
print(get_twin)
# Update digital twin
patch = [
{
"op": "replace",
"path": "/Prop1",
"value": 13
}
]
updated_twin = service_client.update_digital_twin(digital_twin_id, patch)
print('Updated Digital Twin:')
print(updated_twin)
# Delete digital twin
service_client.delete_digital_twin(digital_twin_id)
# Decomission model
service_client.decommission_model(model_id)
# Delete model
service_client.delete_model(model_id)
except HttpResponseError as e:
print("\nThis sample has caught an error. {0}".format(e.message))
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