New Linux CosmosDb image much better but not ready when using Testcontainers

[diegosasw]

Microsoft has released a new docker image which fixes many of the many issues they had.

https://devblogs.microsoft.com/cosmosdb/introducing-the-new-linux-based-azure-cosmos-db-emulator-preview/

I gave it a try manually and it works better, it loads way faster.
However I tried to use it as a test container by providing a .WithImage(imageNameAndTag)

And it doesn't work. It is as if test containers couldn't know when the container is up and running and it's stuck waiting.

I checked logs within container and its traces are very different than the previous versions' traces.

Does the current code need to change to support this image? Could it be changed to ensure it's backwards compatible?

[HofmeisterAn]

It is as if test containers couldn't know when the container is up and running and it's stuck waiting.

If the current wait strategy is not compatible with the new (preview) tag, this is exactly what you’ll notice.

Does the current code need to change to support this image?

Yes, if the upcoming version contains breaking changes.

Could it be changed to ensure it's backwards compatible?

I think the best we can do is figure out what changes are needed to be compatible with the upcoming update and are ready to publish a fix as soon as possible (at least provide guidance as a workaround, like overriding the default builder configuration).

[AButler]

This is how to get the container running:

_container = new CosmosDbBuilder()
                .WithImage("mcr.microsoft.com/cosmosdb/linux/azure-cosmos-emulator:vnext-preview")
                .WithCommand("--protocol", "https")
                .WithEnvironment("ENABLE_EXPLORER", "false")
                .WithWaitStrategy(Wait.ForUnixContainer().AddCustomWaitStrategy(new WaitUntil()))
                .Build();

The WaitUtil class is defined here (it is slightly different URL than the one in the Testcontainers repo):

private sealed class WaitUntil : IWaitUntil
{
    public async Task<bool> UntilAsync(IContainer container)
    {
        // CosmosDB's preconfigured HTTP client will redirect the request to the container.
        const string requestUri = "https://localhost";

        var httpClient = ((CosmosDbContainer)container).HttpClient;

        try
        {
            using var httpResponse = await httpClient.GetAsync(requestUri).ConfigureAwait(false);

            return httpResponse.IsSuccessStatusCode;
        }
        catch (Exception)
        {
            return false;
        }
        finally
        {
            httpClient.Dispose();
        }
    }
}

Note: this new emulator doesn't yet support everything the old one does.

[HofmeisterAn]

Cool, thanks. Did you check if rewriting the HTTP request is still necessary?

[AButler]

@HofmeisterAn Yes, the rewriting is still necessary.

[AButler]

To clarify the commands above,

.WithCommand("--protocol", "https")

is required to use the emulator with the .NET SDK (see https://learn.microsoft.com/en-gb/azure/cosmos-db/emulator-linux#running)

.WithEnvironment("ENABLE_EXPLORER", "false")

is optional as it doesn't start the UI for the Cosmos Explorer, so it speeds up startup time.

The different WaitUntil class is only different in that is checking https://localhost rather than https://localhost/_explorer/emulator.pem. This is because the Cosmos Explorer is no longer hosted at /_explorer and the certificate isn't exposed.