In an Azure function the run method creates an ILogger which in my main class I can use to log errors and information, however, I am using helper classes to run my Graph API and Cosmos DB queries.
What is the best way to log errors and information in the separate classes, should I be passing the log in all my classes or methods? or is there a better way to make the ILogger available to all classes at runtime?
public class AzureFunction
{
public Task Run([TimerTrigger("0 0 1 * * *")] TimerInfo myTimer, ILogger log)
{
log.LogInformation("This message logs correctly");
GraphHelper graphHelper = new GraphHelper();
graphHelper.GetGraphData();
}
}
public class GraphHelper
{
public void GetGraphData()
{
try
{
asyncTask()
}
catch (Exception ex)
{
log.LogInformation($"{ex.Message} - How can I log this without passing ILogger to every class or method?");
}
}
}
The right way (IMHO) is through dependency injection.
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Text;
namespace FunctionApp1
{
public class HelperClass : IHelperClass
{
private static ILogger<IHelperClass> _logger;
public HelperClass(ILogger<IHelperClass> logger)
{
_logger = logger;
}
public void Dowork()
{
_logger.LogInformation("Dowork: Execution Started");
/* rest of the functionality below
.....
.....
*/
_logger.LogInformation("Dowork: Execution Completed");
}
}
}
host.json
{
"version": "2.0",
"logging": {
"applicationInsights": {
"samplingExcludedTypes": "Request",
"samplingSettings": {
"isEnabled": true
}
},
"logLevel": {
"FunctionApp1.HelperClass": "Information"
}
}
}
Helper class
using System;
using System.Collections.Generic;
using System.Text;
namespace FunctionApp1
{
public interface IHelperClass
{
void Dowork();
}
}
MainFunction
using System;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Host;
using Microsoft.Extensions.Logging;
namespace FunctionApp1
{
public class MainFunction // Ensure class is not static (which comes by default)
{
private IHelperClass _helper;
public MainFunction(IHelperClass helper)
{
_helper = helper;
}
[FunctionName("MainFunction")]
public void Run([TimerTrigger("0 */1 * * * *")]TimerInfo myTimer, ILogger log)
{
log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");
// call helper
_helper.Dowork();
}
}
}
Startup.cs
using Microsoft.Azure.Functions.Extensions.DependencyInjection; // install nuget - "Microsoft.Azure.Functions.Extensions"
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Text;
[assembly: FunctionsStartup(typeof(FunctionApp1.Startup))]
namespace FunctionApp1
{
public class Startup : FunctionsStartup
{
public override void Configure(IFunctionsHostBuilder builder)
{
builder.Services.AddSingleton<IHelperClass,HelperClass>();
}
}
}
A Full sample can be found on https://gist.github.com/nareshnagpal06/82c6b4df2a987087425c32adb58312c2