feat(ec2): dry run connection script to surface errors earlier.

[Hweinstock]

Problem

Follow up to #6018 (comment)

Solution

• Run ssh within the same env as it will be run on real connection.
• Log any resulting errors, and inform user where the process failed.
• Also part of this PR is moving some functions to remoteSession.ts that are general enough to be there.

Error msg:

---

License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
  • Confirm whether tests should be added or ensure the PR description explains why tests are not required.
• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
  • Note: beta or "experiment" features that have active users should announce fixes in the changelog.
  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.

[justinmk3]

not a blocker: for connecting to a Windows machine would we need a different test command? or does this command work on powershell?

[Hweinstock]

Since we directly invoke the sshPath I believe this should still work. However, once I add some tests for this function I will hopefully have a better idea.

[justinmk3]

Awesome

[justinmk3]

can we capture the output of this process invocation and include it in the logs?

we may even want to use a similar approach as collectSamErrors (which should probably be lifted into errors.ts, and generalized a bit) to collect errors, and include them in the user-facing message.

aws-toolkit-vscode/packages/core/src/shared/sam/cli/samCliInvokerUtils.ts

Line 75 in 3d46b7b

export function collectSamErrors(samOutput: string): string[] {

[Hweinstock]

I believe the output is already in the logs because we bind a logger to the process:

aws-toolkit-vscode/packages/core/src/awsService/ec2/model.ts

Lines 248 to 252 in 823a0e3

	const SessionProcess = createBoundProcess(envProvider).extend({
	onStdout: logger,
	onStderr: logger,
	rejectOnErrorCode: true,
	})

Do you think its worth filtering the logs? I agree that collectSamErrors method could definitely be generalized and potentially applied here as a filter, but unsure what to filter for.