opentelemetry-dotnet/examples/AspNetCore/Controllers/WeatherForecastController.cs

72 lines
2.8 KiB
C#

// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
namespace Examples.AspNetCore.Controllers;
using System.Diagnostics;
using System.Diagnostics.Metrics;
using System.Security.Cryptography;
using Examples.AspNetCore;
using Microsoft.AspNetCore.Mvc;
[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
private static readonly string[] Summaries =
[
"Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
];
private static readonly HttpClient HttpClient = new();
private readonly ILogger<WeatherForecastController> logger;
private readonly ActivitySource activitySource;
private readonly Counter<long> freezingDaysCounter;
public WeatherForecastController(ILogger<WeatherForecastController> logger, InstrumentationSource instrumentationSource)
{
this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
ArgumentNullException.ThrowIfNull(instrumentationSource);
this.activitySource = instrumentationSource.ActivitySource;
this.freezingDaysCounter = instrumentationSource.FreezingDaysCounter;
}
[HttpGet]
public IEnumerable<WeatherForecast> Get()
{
using var scope = this.logger.BeginIdScope(Guid.NewGuid().ToString("N"));
// Making a http call here to serve as an example of
// how dependency calls will be captured and treated
// automatically as child of incoming request.
var res = HttpClient.GetStringAsync(new Uri("http://google.com")).Result;
// Optional: Manually create an activity. This will become a child of
// the activity created from the instrumentation library for AspNetCore.
// Manually created activities are useful when there is a desire to track
// a specific subset of the request. In this example one could imagine
// that calculating the forecast is an expensive operation and therefore
// something to be distinguished from the overall request.
// Note: Tags can be added to the current activity without the need for
// a manual activity using Activity.Current?.SetTag()
using var activity = this.activitySource.StartActivity("calculate forecast");
var forecast = Enumerable.Range(1, 5).Select(index => new WeatherForecast
{
Date = DateTime.Now.AddDays(index),
TemperatureC = RandomNumberGenerator.GetInt32(-20, 55),
Summary = Summaries[RandomNumberGenerator.GetInt32(Summaries.Length)],
})
.ToArray();
// Optional: Count the freezing days
this.freezingDaysCounter.Add(forecast.Count(f => f.TemperatureC < 0));
this.logger.WeatherForecastGenerated(LogLevel.Information, forecast.Length, forecast);
return forecast;
}
}