Output JSON in Azure Function Logs

问题

We'd like to send structured log data from our Azure Functions to Event Hub. So I set up Serilog to log to the console and include all the info I wanted. But now I come to try this in Azure, all of my nice Json formatted data from Serilog is being ignored - and only the standard ILogger output is being shown :(

Here's the config I'm using in Startup.ConfigureServices.

services.AddLogging(loggingBuilder => loggingBuilder.AddSerilog(CreateLogger()));

private static Logger CreateLogger()
{
    var loggerConfig = new LoggerConfiguration()
    .Enrich.FromLogContext()
    .Enrich.WithCorrelationIdHeader("X-Request-Id")
    .WriteTo.Console(new ElasticsearchJsonFormatter())
    .WriteTo.File(new ElasticsearchJsonFormatter(),
        $@"D:\home\LogFiles\Application\{applicationName}.txt",
        fileSizeLimitBytes: 1_000_000,
        rollOnFileSizeLimit: true,
        shared: true,
        flushToDiskInterval: TimeSpan.FromSeconds(1));

}

Then I'm logging using ILogger in my function:

[FunctionName("Health")]
public IActionResult Health([HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "users/health")] 
    HttpRequest req, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a health request.");
    return new OkObjectResult("Users is healthy");
}

And locally I get both logs - the normal text C# HTTP trigger function processed a health request. but also a big JSON blob as expected. However, when running in Azure, when I look in Log Stream, I only see the normal text log :(

I can see the expected output in the file - but I want to be able to use Diagnostic settings to export the logs - and I can't select a log file there! :(

来源：https://stackoverflow.com/questions/62199104/output-json-in-azure-function-logs

标签

azure-functions

azure-eventhub

serilog

ilogger