Selectively skip and fix tests after PR#212

[dliappis]

PR #212 made some changes on main that require the presence of MANIFEST_URL. However, the pipeline is still configured to run the same script when a PR (from an upstream branch) is raised and it currently fails.

This commit skips tests when triggered from another pipeline (unified release), and allows running tests when triggered by PR creation, or branch pushed by picking up a suitable MANIFEST_URL.

[dliappis]

This is ready for review. Because of the multiple ways that this pipeline may run -- via unified release trigger, via branch commits or pr commits -- we need to support a different way of running depending on the occasion:

1. If we open the PR it (e.g. the latest commit here: https://buildkite.com/elastic/elastic-stack-installers/builds/3646) it looks like:

   

2. If the pipeline gets triggered by the unified release it should run as before (and allow to go through the DRA publish).

3. Special handling is done for staging builds:

   • Unified release may trigger the pipeline but only for non main branches and specifically if they target [0-9]+.[0-9]+ matching branches. Tests are skipped.
   • PRs are only allowed to run the steps (including tests) if they target non-main branch (the reason is that there is no https://staging.elastic.co/latest/main.json, so we can't deduce a valid MANIFEST_URL)

4. We've removed runs based on push events -- e.g. cutting a new branch from main -- (which used to be allowed before); this is because it complicates unnecessarily the conditionals. This use case (and more) will be covered in a follow up PR, through a scheduled job that runs at regular intervals.

Example run: https://buildkite.com/elastic/elastic-stack-installers/builds/3718#018d6acc-6f2e-43b8-b8ea-3514dd9f919e using this PR

[dliappis]

@strawgate to implement what we discussed in do you think it would it be enough to just present a variable here (which is the conditional that covers the case that our job/scripts gets triggered from the unified release) and conditionally run tests in

elastic-stack-installers/.buildkite/scripts/build.ps1

Line 185 in d1bdb21

& (Join-Path $PSScriptRoot "test.ps1")

only if the var is present?

[strawgate]

@strawgate to implement what we discussed in do you think it would it be enough to just present a variable here (which is the conditional that covers the case that our job/scripts gets triggered from the unified release) and conditionally run tests in

elastic-stack-installers/.buildkite/scripts/build.ps1

Line 185 in d1bdb21

& (Join-Path $PSScriptRoot "test.ps1")

only if the var is present?

Yes!

[dliappis]

@strawgate to implement what we discussed in do you think it would it be enough to just present a variable here (which is the conditional that covers the case that our job/scripts gets triggered from the unified release) and conditionally run tests in

elastic-stack-installers/.buildkite/scripts/build.ps1

Line 185 in d1bdb21

& (Join-Path $PSScriptRoot "test.ps1")

only if the var is present?

Yes!

@strawgate this has been implemented in b1c05ba . Please take a look.

[dliappis]

close #225 in favor of #235