Azure NodeJS console log

Question

I have a Visual Studio Enterprise MSDN subscription so I decided to move from Heroku to Microsoft Azure because I used to pay: now I don't. My Service Plan is the D1. I wish I can trail the console.log strings of my Node JS application deployed on my Azure platform. My service plan is the shared one named I deployed the app code on BitBucket and linked my repo to the application with a correct destribution. Correct means I see the green check flag. I deployed, on the main folder of the app, a file named IISNode.yml, here is the content:

nodeProcessCommandLine: "D:\Program Files (x86)\nodejs\0.12.6\node.exe"
loggingEnabled: true
debuggingEnabled: false
devErrorsEnabled: false
node_env: production

The firse line I copied from the iisnode.yml created by Azure itselves. The other lines I am not quite sure about the exact meanings of all of them, but I figured they were enough. If I visit the url: http://MY_APP_NAME.scm.azurewebsites.net/DebugConsole I can click on Tools->Log Stream menu but the page remains on loading. I can reach the Azure Portal, enter my node app, Tools -> Application Log and Web Server log. The application log shows this (I think quite interesting) message:

System.ApplicationException: The trace listener AzureBlobTraceListener is disabled. ---> System.InvalidOperationException: The SAS URL for the cloud storage account is not specified. Use the environment variable 'DIAGNOSTICS_AZUREBLOBCONTAINERSASURL' to define it.
   at Microsoft.WindowsAzure.WebSites.Diagnostics.AzureBlobTraceListener.RefreshConfig()

I have not reached informations about this "environment variable", and I can0t guess what the BLOB container has to do with my log application. And: what is the correct value for this variable? And if there is any, why is that one correct?

The Web Servier log is are empty. I can see http activities from the monitor of the app on the same portal, but still no log.

Am I missing something ? I decided to install Visual Studio, maybe this will help? I hope this has tools to be integrated with Azure for good. Meanwhile, where is the console log of my (Extremely Simple) node application?

Answer 1

You can view your logs in real time if you use the azure SCM interface. This can usually be accessed on the following url

https://{{ name of webapp }}.scm.azurewebsites.net/api/logstream

All your console output from your application is redirected here.

You can also use curl:

curl -u {{ deploymentCredentialsUsername:deploymentCredentialsPassword }} https://webapp-name.acm.azurewebsites.net/api/logstream

Otherwise you could use the nodejs azure cli. Install it with

npm install -g azure-cli

Switch to asm mode:

azure config mode asm

Then you can proceed to look at the logs from your terminal:

azure site log tail {{ webapp name }}

Answer 2

You can add an item in iisnode.yml named logDirectory, set the value as iisnode for example, then the application will create a folder in this name in your root directory and store files with stdout and stderr captures in it. You can refer to https://github.com/tjanczuk/iisnode/blob/master/src/samples/configuration/iisnode.yml#L94 for the details for this configuration.

You can store logs in files whatever you need via console.log(), then the application will create a html file index.html in the log folder to provide logs. You can visit the logs via the URL: http://<you_app_name>.azurewebsites.net/<log_file_name>/index.html

Additionally, you can leverage Node.js console class to customize logger, refer to https://nodejs.org/api/console.html#console_new_console_stdout_stderr for the sample