There are too many functions in your function app, they may interact each other. I met similar problem with this, in that case, the timer trigger functions in one function app and did not work. But when i deploy them to different function apps, they work fine. so you can try to deploy your second function to another function app.

And I suggest you report this problem to Microsoft, they can know more information about this problem, and may have a better solution.

AFAIK, There is no specific reason for the timer trigger not firing properly within the given time.

Few of the workaround we can follow,

I have not faced the similar issue yet, would suggest you to please try to restart/refresh your function app. or, It may be due to of the sync issue with the function which is not happening properly.

As suggested by @Anand Sowmithiran the SO THREAD, @MayankBargali-MSFT suggest about singleton lock i,e;

TimerTrigger uses the Singleton feature of the WebJobs SDK to ensurethat only a single instance of your triggered function is running atany given time. When the JobHost starts up, for each of yourTimerTrigger functions a blob lease (the Singleton Lock) is taken. This distributed lock ensures that only a single instance of yourscheduled function is running at any time. If the blob for thatfunction is not currently leased, the function will acquire the leaseand start running on schedule immediately. If the blob lease cannot beacquired, it generally means that another instance of that function isrunning, so the function is not started in the current host.

Also please try to set runonstartup to false to check whether its behaving the same or not as provided the MS DOC in comment.

For more information Please refer the below links :-

• MS Q&A| Azure Timer Trigger not firing

• GitHub | azure timer function not executing all of sudden

Thanks to JaliyaUdagedara for answering to this thread - Azure Function (REST API for Http Trigger & using Timer Trigger with Azure Data Factory) - Microsoft Q&A

So, if I use Timer Trigger and have a logic to pull list of data, how do I move the data to ADF?

As far as I know, ADF cannot directly use Timer trigger function.

But you can create schedule triggers in Azure Data Factory first:

Then create a new Http Trigger Function, and write the logic originally written in Time Trigger Function in Time Trigger Function. Then use the Http trigger function in ADF.

For how to use azure function in ADF, you can refer to this blog.

The logs of azure function is fragile. So sometimes you can not see the logs, but this doesn't mean the azure function is not run.

If you want to know the function is running you need to go to the kudu of your azure function and see the logs file of your function app.(The logs in Application Insights is coming from this place.)

The logs file is in the place:

Open your brower and go to https://yourfunctionappname.scm.azurewebsites.net/DebugConsole, and then click into LogFiles/Application/Functions/Function/yourtriggername . You will find the log file in this place.

I have reproduced in my environment by taking both the HTTP and Timer Trigger Functions in the same Function Class file - Python Version 3.9.13

Local Execution:

Configuration:

1. Created Azure Function App (Python) and Key Vault.
2. Enabled System Assigned Managed Identity in Azure Function App.
3. In Key Vault, Added the Secret with the value and also in Access Configuration > Add Policy > Key and Secret Management, Principal - Function App System Assigned Managed Identity Object Id.
4. Add the Key Vault Name App Setting and Python v2 model app setting called "AzureWebJobsFeatureFlags": "EnableWorkerIndexing" to the Function App Configuration.

Azure Cloud Portal - Function App Execution:

1. Published to Azure Portal Function App using below Command:

func azure functionapp publish <your_FunctionApp_Name_inTheAzurePortal>

1. After Publishing to the Azure Portal Function App, I have added 2 app settings in the Configuration Menu of Azure Function App:

Note: You can add them either before or after publishing to the Azure Portal.

And I can see both the Functions:

Http Trigger Function Run:

Timer Trigger Function Run:

Code Snippets:

function_app.py:

import  azure.functions  as  func
import  logging
import  datetime
import  os
from  azure.keyvault.secrets  import  SecretClient
from  azure.identity  import  DefaultAzureCredential

app = func.FunctionApp()
@app.function_name(name="HttpTrigger1")     #Http_Trigger
@app.route(route="hello")

def  test_function(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request.')

utc_timestamp = datetime.datetime.utcnow().replace(
tzinfo=datetime.timezone.utc).isoformat()

keyVaultName = os.environ["KEY_VAULT_NAME"]
logging.info(f'TestEnvFromKeyVault: {keyVaultName}')
logging.info('Python Http trigger function ran at %s', utc_timestamp)
return  func.HttpResponse("Hello Krishna, This HTTP triggered function executed successfully.",
status_code=200
)

# Timer_Trigger_in_same_function

@app.function_name(name="mytimer")
@app.schedule(schedule="0 */1 * * * *", arg_name="mytimer", run_on_startup=True,
use_monitor=False)
def  test_function(mytimer: func.TimerRequest) -> None:

utc_timestamp = datetime.datetime.utcnow().replace(
tzinfo=datetime.timezone.utc).isoformat()

if  mytimer.past_due:
logging.info('The timer is past due!')
logging.info('Python timer trigger function ran at %s', utc_timestamp)

host.json:

{
    "version": "2.0",
    "logging": {
    "applicationInsights": {
    "samplingSettings": {
    "isEnabled": true,
    "excludedTypes": "Request"
        }
    }
},
"extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[3.15.0, 4.0.0)"
    }
}

requirements.txt file:

azure-functions
azure.keyvault.secrets
azure.identity
azure-keyvault

local.settings.json:

{

"IsEncrypted": false,
"Values": {
    "FUNCTIONS_WORKER_RUNTIME": "python",
    "AzureWebJobsStorage": "DefaultEndpointsProtocol=https;AccountName=krishfunappstorage;AccountKey=<Storage-Account-Access_Key>;EndpointSuffix=core.windows.net",
    "AzureWebJobsFeatureFlags": "EnableWorkerIndexing",
    "KEY_VAULT_NAME":"krishkv4funapp"
}
}

Above parts of code sample taken from the below references:

1. Python Azure Functions Code from this MS Doc.
2. Function App Publish Command from this MS Doc Reference