Azure Sphere logging

Kiran Pradeep 106

For Sphere devices, we can vscode/cli to deploy, debug and see logs of the application [1]. But later (say I kept it running for 24 hours and comes back), if I wish to see application logs, it looks like, I don't have a way. Is there a way to see application logs on Sphere development boards without initiating the debugger?

To be clear, this is not about monitoring applications deployed in production [2]. This is only about development logs on Azure Sphere development boards. An example is logcat in Android [3]. The intention is to analyse long running application on Azure Sphere. We cannot keep the debugger attached forever.

1 answer

António Sérgio Azevedo 7,661 Reputation points Microsoft Employee

2020-10-29T16:27:45.19+00:00
Hello @Kiran Pradeep ,
Please check the article on Best Practices for high-level applications - Error handling and logging

For your case, where you want to analyse long running application on Azure Sphere without attaching the debugger the best and recommended approach is to send the value of the errno variable through D2C messages to an IoT Hub.

===UPDATE====

Alternatively you can capture/redirect the output stream to a file:
https://learn.microsoft.com/en-us/azure-sphere/app-development/manual-build#debug-the-application

You don’t actually need to use gdb/debugger to access this output stream from a connected device. A terminal client reading that stream can save/redirect their output to file.

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2 people found this answer helpful.
Kiran Pradeep 106 Reputation points

2020-10-30T16:08:49.103+00:00

Again to confirm, I am not asking for logs of applications running in Production device group. This is only for development testing (device groups: Development/FieldTesting). But even during development testing, I cannot attach debugger for say 72 hours (+ that would result in non production performance). Does the answer remain same? If yes, I will be hugely disappointed. I cannot imagine streaming all logs to IoT Hub as D2C messages!

I like to see how my application behaved over time. Errno is just not sufficient.

António Sérgio Azevedo 7,661 Reputation points Microsoft Employee

2020-11-02T16:06:25.647+00:00

Hi @Kiran Pradeep ,
I have talked with the team and confirmed that you can capture/redirect the output stream to a file:

https://learn.microsoft.com/en-us/azure-sphere/app-development/manual-build#debug-the-application

You don’t actually need to use gdb/debugger to access this output stream from a connected device. A terminal client reading that stream can save/redirect their output to file .

I will update the answer with this info if you accept it.

Thanks

António Sérgio Azevedo 7,661 Reputation points Microsoft Employee

2020-11-19T12:11:20.607+00:00

Hello @Kiran Pradeep please let us know if you have further questions or you can accept the answer?

Thank you!

Kiran Pradeep 106 Reputation points

2020-11-23T06:00:41.04+00:00

Thanks for the answer and the effort. I will try this out later. But I feel that will work. Humbly requesting you to update the answer and I will accept the same.

António Sérgio Azevedo 7,661 Reputation points Microsoft Employee

2020-11-23T12:32:06.46+00:00

Thank you so much @Kiran Pradeep I have updated the answer. Please do follow-up if needed :).

Kiran Pradeep 106 Reputation points

2021-03-03T15:04:04.393+00:00

Unaccepting the answer as just now I tried this out and it did not work. We can get logs output stream only if debugger is attached. I mean if we initiate as azsphere device app start --debug-mode --component-id <ComponentId>, then the target process is put on hold until we connect the debugger and follow until step 7 and issue c. The terminal client does not get log results until we attach the debugger and follow till step 7.

António Sérgio Azevedo 7,661 Reputation points Microsoft Employee

2021-03-10T01:52:16.593+00:00

Hello Kiran,
We have built a sample to help on Obtaining debug output for a device not connected to a development PC -> https://learn.microsoft.com/en-us/azure-sphere/app-notes/debug-output#obtaining-debug-output-for-a-device-not-connected-to-a-development-pc

"If your devices are connected to a network, you might want to send the debug output over the network to an application that can collect and analyze the information. This Azure Sphere Gallery application demonstrates how to override the default Log_Debug behavior to send and receive that output over a UDP socket."

Please can you give it a try and let me know if this is what you were looking for?

Thank you so much!

Kiran Pradeep 106 Reputation points

2021-03-10T06:33:04.32+00:00

Thanks for the reply. I was trying to follow the article you linked above and saw a line as below.

Obtaining debug log information when a device is connected to a development PC is fairly straightforward.

In my case sphere device is connected to development PC. More importantly, this information is actually inline with your above comment on 2/Nov/2020, which is as below

You don’t actually need to use gdb/debugger to access this output stream from a connected device. A terminal client reading that stream can save/redirect their output to file .

So I like to take that route first. So as per your comment, i should not need to attach/start the debugger. I felt that track was more appropriate for me. Am I not advised to follow that route anymore? If not, I will follow the new route suggested

António Sérgio Azevedo 7,661 Reputation points Microsoft Employee

2021-03-13T00:10:17.05+00:00

@Kiran Pradeep sorry for the confusion. Docs have changed so did the location. This is the document I pointed before with some slight changes:

https://learn.microsoft.com/en-us/azure-sphere/app-development/debug-hl-app?tabs=cliv2beta%2Cwindows&pivots=cli - You can see how to do it using CLI. Is this going into the right direction of what you are trying to achieve?

Can you describe better what is step 7 in this new doc and what is your expected outcome? I am afraid I am not fully understanding your scenario and want to be sure I have it more clear.

Thank you so much!

Kiran Pradeep 106 Reputation points

2021-03-15T03:11:23.077+00:00

I am tired of explaining this. I will close this question and re raise a new question so that there is no ambiguiity. Thanks for all your effort.
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