TelemetryFactoryHostedService.cs

// <copyright file="TelemetryFactoryHostedService.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 OpenTelemetry.Extensions.Hosting.Implementation
{
    using System;
    using System.Threading;
    using System.Threading.Tasks;
    using Microsoft.Extensions.DependencyInjection;
    using Microsoft.Extensions.Hosting;
    using OpenTelemetry.Trace;

    internal class TelemetryFactoryHostedService : IHostedService
    {
        private readonly IServiceProvider serviceProvider;

        public TelemetryFactoryHostedService(IServiceProvider serviceProvider)
        {
            this.serviceProvider = serviceProvider;
        }

        public Task StartAsync(CancellationToken cancellationToken)
        {
            // Ensure the factory was created when the app starts.
            // This will create and start any configured instrumentations.
            this.serviceProvider.GetRequiredService<TracerFactoryBase>();

            return Task.CompletedTask;
        }

        public Task StopAsync(CancellationToken cancellationToken)
        {
            return Task.CompletedTask;
        }
    }
}