Enable devcontainers in repo.

[mitchdenny]

Description

This is an initial PR to enable devcontainer support in the repo. The goal is to enable the various remote development scenarios (Codespaces, SSH, etc) so that we can test them. This is important because we've added logic to the apphost that can do things like detect it is running in Codespaces and using the Aspire repo under Codespaces is a good way of casually validating everything is working.

Outstanding issues

• Dashboard URL shows as localhost:port/login?t=; whilst Codespaces will automatically remap that URL for us when we click on it, the redirect flow (GitHub auth) looses the token in the URL

Fixes # (issue)

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Link to aspire-docs issue:
  • No

Microsoft Reviewers: Open in CodeFlow

[mitchdenny]

Couple of gotchas. For forwarded ports, it can take some time for Codespaces to generate the TLS cert for the endpoint. You just have to be patient. Part of explicitly forwarding the ports in the .devcontainer.json file is to make sure that its mapped as HTTPS or HTTP as appropriate.

[davidfowl]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[davidfowl]

@mitchdenny one place where we don't detect the codespace and print the right url is here:

We should change this too.

[mitchdenny]

Yeah I was looking at this I made some tweaks last night as an experiment. I can put up a PR.

[davidfowl]

Also it seems like only certain playground examples work?