CodeWithSaar.Extensions.ContainerId 0.0.1

Get the container id

Getting container id is sort of important for diagnostic / logging. It has been working by fetching /proc/self/cgroup for container id until lately, cGroupV2 rolls out, and there need to be new ways to get it.

This repo is a yield of the investigation to aggregate various ways to get container ids for both cGroupV1 or cGroupV2. Shall be able to extend to support other cases as time goes by.

Get Started

docker pull saars/cid
docker run saars/cid

Output:

Container Id: 7f1477ac7aa29f3e52d8d4f25632e9df461a3855cc8cd8ad071ad94181381215

See inspect logs from the worker

• Deploy saars/cid-worker into a Kubernetes cluster.
• Check the logs of the pod: kubectl logs <podName>

info: CodeWithSaar.Extensions.ContainerId.CGroupV1ContainerIdProvider[0] No container id matched.
info: CodeWithSaar.Extensions.ContainerId.CGroupV2ContainerIdProvider[0] Matched. Value: 01d1ad1a7b528295f2d03619b35f995be9ddddcfd2a83c013df129aa6cc4d332
info: CodeWithSaar.ContainerId.Worker.Worker[0] Container Id: 01d1ad1a7b528295f2d03619b35f995be9ddddcfd2a83c013df129aa6cc4d332. Wait for 10 seconds.

• Notice that the first provider missed the container since it doesn't exist. But the second provider got it.

Use the NuGet Package

Add reference

dotnet add package CodeWithSaar.Extensions.ContainerId --prerelease

Use static class

string containerId = await ContainerService.GetContainerIdAsync();

Or use it with dependency injection

1. Register the services:

   services.TryAddContainerIdServices();
   

2. Call inject and use the service:

   private readonly IContainerService _containerService;
   class Consumer(IContainerService containerService)
   {
       _containerService = containerService ?? throw new ArgumentNullException(nameof(containerService));
   }
   
   public Task ShowContainerIdAsync()
   {
       Console.WriteLine(await _containerService.GetContainerIdAsync());
   }