feat: Allow MongoDb module configuration without credentials

[the-avid-engineer]

What does this PR do?

1. Do not require a username/password for mongodb
2. Allow for disabling default credentials for mongodb

Why is it important?

This addresses a regression on #547 as well as adding the ability to not use default credentials; when using credentials in replica set mode, there are additional set up pieces that are tedious; it's 1000x easier to run in replica set mode without credentials. Replica set mode allows users to use transactions

Related issues

• Closes [Enhancement]: Explicit no-authentication mode for MongoDb #982

---

I would love to add a test to prevent another regression, but on my last PR I wasn't able to run the tests locally, and I suspect I still cannot run them

[netlify]

✅ Deploy Preview for testcontainers-dotnet ready!

Name	Link
🔨 Latest commit	f470e4b
🔍 Latest deploy log	https://app.netlify.com/sites/testcontainers-dotnet/deploys/64ef8d53ebdaca0008edc9ed
😎 Deploy Preview	https://deploy-preview-983--testcontainers-dotnet.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[HofmeisterAn]

Thanks for your PR 👍.

This addresses a regression on #547 as well as adding the ability to not use default credentials;

Oh, looks like I missed that requirement during the migration to dedicated modules, thanks.

[HofmeisterAn]

We must ensure that the tests also pass (_ = new MongoDbBuilder(false).Build()). The container instance is capable of executing a MongoDB shell command that relies on the credentials, too. Perhaps we can replace a null string with an empty one.

testcontainers-dotnet/tests/Testcontainers.MongoDb.Tests/MongoDbContainerTest.cs

Lines 36 to 49 in 27611d1

	[Fact]
	[Trait(nameof(DockerCli.DockerPlatform), nameof(DockerCli.DockerPlatform.Linux))]
	public async Task ExecScriptReturnsSuccessful()
	{
	// Given
	const string scriptContent = "printjson(db.adminCommand({listDatabases:1,nameOnly:true,filter:{\"name\":/^admin/}}));";
	// When
	var execResult = await _mongoDbContainer.ExecScriptAsync(scriptContent)
	.ConfigureAwait(false);
	// When
	Assert.True(0L.Equals(execResult.ExitCode), execResult.Stderr);
	}

[the-avid-engineer]

We must ensure that the tests also pass (_ = new MongoDbBuilder(false).Build()). The container instance is capable of executing a MongoDB shell command that relies on the credentials, too. Perhaps we can replace a null string with an empty one.

I don't have a Linux box (I'm assuming it only works on Linux because the test has a Linux trait), so I went with the best bet that not passing those options when username/password are null will certainly work as expected, and I'm not opposed to passing empty strings if that works

[HofmeisterAn]

I extended the tests and executed them against MongoDbBuilder(false), resulting in failures. Afterward, I made some adjustments to the implementation. It appears that we can keep non-nullable while achieving a configuration with no authentication by utilizing empty strings. Kindly share your thoughts on this matter. I am not a MongoDB expert, but curious why MongoDB logs different messages according to the configuration (user vs. w/o user). Probably something you ran into.

We can add something like WithNoAuth() to offer a more explicit API.

[the-avid-engineer]

I do know that mongodb://:@localhost:12345 is not a valid connection string, so it won't work there

I will check the other changes against replica set mode

[HofmeisterAn]

I do know that mongodb://:@localhost:12345 is not a valid connection string, so it won't work there

That's not what GetConnectionString() returns. If you run the MongoDbNoAuthConfiguration test you will see it returns

mongodb://127.0.0.1:56789/

If the username and password is empty it will not be included in the connection string.

[HofmeisterAn]

I will check the other changes against replica set mode

@the-avid-engineer have you had the chance to test the changes in replica set mode? I would like to prepare a new release, and ideal include the changes from this pull request.

[the-avid-engineer]

Sorry, I was preoccupied and not able to test yet. I will do so later tonight

That is good that the connection string is correct, I only assumed it would not handle empty string the same as null

[the-avid-engineer]

@HofmeisterAn I can confirm the empty strings work fine with replica set mode :)

[HofmeisterAn]

Thanks for taking the time 🙏.

[ConMD]

Hi everyone,

hope this is the right place to ask this question:
When will this PR be merged into main?

Would be highly appreciated, if it happens soon :)

[HofmeisterAn]

This has already been merged into the main branch and is released.

testcontainers-dotnet/tests/Testcontainers.MongoDb.Tests/MongoDbContainerTest.cs

Lines 61 to 67 in c0932f2

	public sealed class MongoDbNoAuthConfiguration : MongoDbContainerTest
	{
	public MongoDbNoAuthConfiguration()
	: base(new MongoDbBuilder().WithUsername(string.Empty).WithPassword(string.Empty).Build())
	{
	}
	}