==== Azure function ====

=== Setting up IDE: Visual Studio Code ===

  * Set up IDE https://learn.microsoft.com/de-de/azure/azure-functions/functions-develop-vs-code?tabs=node-v4%2Cpython-v2%2Cisolated-process&pivots=programming-language-python
  * Core Tools installieren https://learn.microsoft.com/de-de/azure/azure-functions/functions-run-local?tabs=windows%2Cisolated-process%2Cnode-v4%2Cpython-v2%2Chttp-trigger%2Ccontainer-apps&pivots=programming-language-python#install-the-azure-functions-core-tools

Use to reload the env variables after installing
<sxh python>
$env:Path = `
[System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + `
[System.Environment]::GetEnvironmentVariable("Path","User")
</sxh>


Install packages locally, to make imports succeed

<sxh python>
pip install -r .\requirements.txt
</sxh>

Make sure you select the right python version, for which you executed the "pip install"

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Then even under windows one can run "func start" to test linux functions

<sxh python>
func start
</sxh>

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=== Debugging Azure functions ===


== Validate Triggers==

Often, if the "Azure Function" code has invalid imports,
then the triggers are missing after the deployment.

You can validate, **if the triggers were recognized successfully**, by starting the Azure Function locally.

The recognized triggers will be listed as following:

{{https://s3.eu-central-1.amazonaws.com/alf-digital-wiki-pics/sharex/4HLTFBqBlR.png}}



== Validate Files ==

Often the files of Azure Function - are not deployed or lost after the terraform-update.

Check if the files are available and up to date.

Maybe teh reason why the trigger isnt there - is because you have not deplyoed the app?

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== Test execute and see output ==

You can execute the Azure functions from the portal.

And you can validate the behavior via "Portal > Azure Function > Log Stream"

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== Validate Imports ==

Just do, to see if the imports are understood correctly:

<sxh python>
pip install -r .\requirements.txt
</sxh>


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=== Azure functions in Azure Portal ===

The runtime
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The trigger and code.

Only available after uploading the code into the function, via 

''az functionapp deployment source config-zip -g $resourceg -n $functionname --src app.zip''

which uploads the ''app.zip'' into the associated blob-container,
from where it automatically is executed by the azure_function.

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Here the function ''http_trigger'' was recognized.

{{https://s3.eu-central-1.amazonaws.com/alf-digital-wiki-pics/sharex/KAkOMqgCRq.png}}

The Function URL
{{https://s3.eu-central-1.amazonaws.com/alf-digital-wiki-pics/sharex/bYSSoOXd9R.png}}

The URL response
{{https://s3.eu-central-1.amazonaws.com/alf-digital-wiki-pics/sharex/TRJIKVCUQ4.png}}


=== Limitations of Azure functions ===


   * Azure functions - are NOT only serverless. 
     * You can choose a premium subscription and deploy your **Azure function**  as an always running instance into your network
     * You CAN'T use a serverless function - in a private network
   * You **CAN'T have multiple triggers** for a function. ONly one of
     * http_trigger
     * Blob trigger
     * CosmosDB trigger
     * EventHub trigger
     * Queue trigger
     * ServiceBus Queue trigger
     * ServiceBus Topic trigger
     * Timer Trigger

=== Serverless Azure functions ===

https://learn.microsoft.com/en-us/azure/azure-functions/functions-proxies



=== Python linux functions ===

https://learn.microsoft.com/en-us/azure/azure-functions/create-first-function-cli-python?tabs=linux%2Cbash%2Cazure-cli%2Cbrowser


Run like https://learn.microsoft.com/en-us/azure/azure-functions/create-first-function-cli-python?tabs=linux%2Cbash%2Cazure-cli%2Cbrowser#run-the-function-locally

<sxh shell>

func start

</sxh>

IN general read about developing locally:
https://learn.microsoft.com/en-us/azure/azure-functions/functions-develop-local



=== Azure Service Bus Pub/Sub ===

Publishing function
<sxh python>
import logging
import azure.functions as func

app = func.FunctionApp()

# vs output into queue for python
# https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-service-bus-output?tabs=python-v2%2Cisolated-process%2Cnodejs-v4%2Cextensionv5&pivots=programming-language-python

@app.route(route="http_trigger_queue", auth_level=func.AuthLevel.ANONYMOUS)
@app.service_bus_queue_output(arg_name="message",
                              connection="ServiceBusConnection",
                              queue_name="alfdevapi5servicebusqueue")
def http_trigger_queue(req: func.HttpRequest, message: func.Out[str]) -> func.HttpResponse:
    logging.info('Python HTTP trigger function processed a request.')

    logging.info('Python HTTP trigger function processed a request.')
    myMessage = "Hi alf this is my message via the queue to you."
    logging.info(myMessage)
    
    input_msg = req.params.get('message')
    message.set(f"{myMessage} {input_msg}")

    return func.HttpResponse(
        "This function should process queue messages.",
        status_code=200
    )
</sxh>


Subscribing function
<sxh python>
import logging
import azure.functions as func

app = func.FunctionApp()


@app.service_bus_queue_trigger(arg_name="azservicebus", queue_name="alfdevapi5servicebusqueue",
                               connection="ServiceBusConnection") 
def servicebus_trigger(azservicebus: func.ServiceBusMessage):
    logging.warn('Python ServiceBus Queue trigger processed a message: %s',
                azservicebus.get_body().decode('utf-8'))
</sxh>

Here you can see, that when the publishing function is executed, via Test

Then the consuming function is receiving the message from the queue.

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=== Azure Functions Java ===

https://stackoverflow.com/questions/77360325/cannot-create-java-function-in-azure-function-app

<sxh java>
mvn clean install
mvn azure-functions:run
mvn azure-functions:deploy
</sxh>

Java SDK content
  * https://azure.github.io/azure-sdk-for-java/servicebus.html
  * https://learn.microsoft.com/en-us/java/api/com.azure.messaging.servicebus.servicebusclientbuilder?view=azure-java-stable
  * 


=== Azure Service Topic Pub with session ===

requirements.txt
<sxh python>
# DO NOT include azure-functions-worker in this file
# The Python Worker is managed by Azure Functions platform
# Manually managing azure-functions-worker may cause unexpected issues

azure-functions
datetime
azure-servicebus

</sxh>

local.settings.json
<sxh python>

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "",
    "FUNCTIONS_WORKER_RUNTIME": "python",
    "AzureWebJobsFeatureFlags": "EnableWorkerIndexing",
    "ServiceBusConnection": "Endpoint=sb://alfdevapi6sb.servicebus.windows.net/;SharedAccessKeyName=alfdevapi6servicebus_auth_rule;SharedAccessKey=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx="
  }
}

</sxh>


Python V2 app, which uses the Python SDK, to send messages with SessionId

  * [[https://learn.microsoft.com/en-us/azure/developer/python/sdk/azure-sdk-overview?view=azure-python|Use the Azure libraries (SDK) for Python]]
  *  [[https://learn.microsoft.com/en-us/python/api/azure-servicebus/azure.servicebus.servicebusclient?view=azure-python|ServiceBusClient Class]]

<sxh python>
import logging
import azure.functions as func
from datetime import datetime
import json
from azure.servicebus import ServiceBusClient, ServiceBusMessage
import os

app = func.FunctionApp(http_auth_level=func.AuthLevel.ANONYMOUS)

# vs output into queue for python
# https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-service-bus-output?tabs=python-v2%2Cisolated-process%2Cnodejs-v4%2Cextensionv5&pivots=programming-language-python


TOPIC_NAME_A = "alfdevapi6topic" 
CONN_STRING = os.environ['ServiceBusConnection']
SESSION_ID = "008"


@app.route(route="http_trigger")
def http_trigger(req: func.HttpRequest) -> func.HttpResponse:
    logging.info('Python HTTP trigger function processed a request.')
    myMessage = "Hi alf this is my message via the queue to you."

    jsn_message_envelope =  generateMessage(myMessage, SESSION_ID)
    logging.info(f"Will send envelope: {jsn_message_envelope}")

    servicebus_client = ServiceBusClient.from_connection_string(conn_str=CONN_STRING)
    rith_sen = servicebus_client.get_topic_sender(TOPIC_NAME_A)
    rith_msg = ServiceBusMessage(jsn_message_envelope)
    rith_msg.session_id = SESSION_ID
    with rith_sen:
        rith_sen.send_messages(rith_msg)
    servicebus_client.close()


    return func.HttpResponse(
            "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response.",
            status_code=200
    )


def generateMessage(myMessage, mySessionId):
    now = datetime.now()
    print("now =", now)
    logging.info(f"Time stamp: {now}")

    dt_string = now.strftime("%d/%m/%Y %H:%M:%S")

    my_json_string = f"""
    {{
        "body": "{myMessage}",
        "customProperties": {{
            "timePublish": "{dt_string}",
        }},
        "brokerProperties": {{
            "SessionId": "{mySessionId}"
        }}
    }}
    """

    return my_json_string

</sxh>

== Publish a test message ==

Publishing a message

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And see, which session was used during publishing, here ''session1''

{{https://s3.eu-central-1.amazonaws.com/alf-digital-wiki-pics/sharex/AegrzHZAfS.png}}

== Consuming a test message ==

Now a consumer can consume the message

{{https://s3.eu-central-1.amazonaws.com/alf-digital-wiki-pics/sharex/at6eSPYnFS.png}}