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

88 lines
3.4 KiB
C#

// <copyright file="WeatherForecastController.cs" company="OpenTelemetry Authors">
// Copyright The OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// </copyright>
namespace Examples.AspNetCore.Controllers;
using System.Diagnostics;
using System.Diagnostics.Metrics;
using Examples.AspNetCore;
using Microsoft.AspNetCore.Mvc;
[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
private static readonly string[] Summaries = new[]
{
"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, Instrumentation instrumentation)
{
this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
ArgumentNullException.ThrowIfNull(instrumentation);
this.activitySource = instrumentation.ActivitySource;
this.freezingDaysCounter = instrumentation.FreezingDaysCounter;
}
[HttpGet]
public IEnumerable<WeatherForecast> Get()
{
using var scope = this.logger.BeginScope("{Id}", Guid.NewGuid().ToString("N"));
// Making an 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("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 Acitivty.Current?.SetTag()
using var activity = this.activitySource.StartActivity("calculate forecast");
var rng = new Random();
var forecast = Enumerable.Range(1, 5).Select(index => new WeatherForecast
{
Date = DateTime.Now.AddDays(index),
TemperatureC = rng.Next(-20, 55),
Summary = Summaries[rng.Next(Summaries.Length)],
})
.ToArray();
// Optional: Count the freezing days
this.freezingDaysCounter.Add(forecast.Count(f => f.TemperatureC < 0));
this.logger.LogInformation(
"WeatherForecasts generated {count}: {forecasts}",
forecast.Length,
forecast);
return forecast;
}
}