CLOUDP-295785 - move away from GHA variables (#388)

# Summary

GitHub Variables cannot be accessed from forks. Forks are used by
engineers to create PRs in this repo, but due to previously mentioned
limitation some GitHub Actions fail.

This PR moves the variables from GitHub to `root-context` file.
Additionally to make contexts work in GitHub Actions I had to create
`gha-private-context` file similar to `evg-private-context`, otherwise
the switch command would fail.

After this change all GitHub variables can be removed.

## Proof of Work

Passing evg CI and GitHub Checks.

## Checklist

- [x] Have you linked a jira ticket and/or is the ticket in the title?
- [x] Have you checked whether your jira ticket required DOCSP changes?
- [x] Have you added changelog file?
    - use `skip-changelog` label if not needed
- refer to [Changelog files and Release
Notes](https://github.com/mongodb/mongodb-kubernetes/blob/master/CONTRIBUTING.md#changelog-files-and-release-notes)
section in CONTRIBUTING.md for more details

Author: MaciejKaras

.github/actions/setup-ubuntu-host/action.yml

@@ -9,7 +9,7 @@ runs:
     - name: setup python
       uses: actions/setup-python@v5
       with:
-        python-version: ${{inputs.python-version}}
+        python-version: '${{ inputs.python-version }}'
         cache: 'pip' # caching pip dependencies
     - name: Install dependencies
       shell: bash

.github/actions/switch-context/action.yml

@@ -0,0 +1,18 @@
+name: 'Switch context and export all environment variables'
+inputs:
+  context-name:
+    description: 'Context name to switch to'
+    required: true
+runs:
+  using: "composite"
+  steps:
+    - name: Switch context
+      shell: bash
+      run: |
+        echo "Initializing context files"
+        cp scripts/dev/contexts/gha-private-context scripts/dev/contexts/private-context
+        scripts/dev/switch_context.sh ${{inputs.context-name}}
+        echo "Finished initializing to the ${{inputs.context-name}}"
+        while read line; do
+          echo "$line" >> $GITHUB_ENV
+        done < <(tail -n +5 .generated/context.env | sed 's/\"//g')

.github/workflows/preview_release_notes.yml

@@ -21,18 +21,22 @@ jobs:
         uses: actions/checkout@v4
         with:
           fetch-depth: '0'
+      - name: Switch to root context
+        id: switch_context
+        uses: ./.github/actions/switch-context
+        with:
+          context-name: 'root-context'
       - name: Setup host
         uses: ./.github/actions/setup-ubuntu-host
         with:
-          python-version: '${{ vars.PYTHON_VERSION }}'
+          python-version: ${{ env.PYTHON_VERSION }}
       - name: Generate Release Notes
-        id: generate_release_notes
         run: python -m scripts.release.release_notes -s $INITIAL_COMMIT_SHA -v $INITIAL_VERSION -o release_notes_tmp.md
         env:
           # We can not use environments set via GitHub UI because they will
           # not be available in the pull requests running from forks.
-          INITIAL_COMMIT_SHA: 9ed5f98fc70c5b3442f633d2393265fb8a2aba0c
-          INITIAL_VERSION: 1.3.0
+          INITIAL_COMMIT_SHA: ${{ env.INITIAL_COMMIT_SHA }}
+          INITIAL_VERSION: ${{ env.INITIAL_VERSION }}
       - name: Add disclaimer to release notes preview
         run: |
           echo -e "_:warning: (this preview might not be accurate if the PR is not rebased on current master branch)_\n" > release_notes_preview.md

.github/workflows/require_changelog.yml

@@ -22,10 +22,15 @@ jobs:
         uses: actions/checkout@v4
         with:
           fetch-depth: '0'
+      - name: Switch to root context
+        id: switch_context
+        uses: ./.github/actions/switch-context
+        with:
+          context-name: 'root-context'
       - name: Setup host
         uses: ./.github/actions/setup-ubuntu-host
         with:
-          python-version: '${{ vars.PYTHON_VERSION }}'
+          python-version: ${{ env.PYTHON_VERSION }}
       - name: Check if changelog entry file was added in this PR
         run: |
           set -o pipefail

scripts/dev/contexts/gha-private-context

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+set -Eeou pipefail
+
+export NAMESPACE=""
+export CLUSTER_NAME=""
+export LOCAL_OPERATOR="false"
+export BASE_REPO_URL=""

scripts/dev/contexts/root-context

@@ -129,3 +129,7 @@ fi
 # but we can unify once we are done with unified operator
 # installation for both multicluster and single cluster setups.
 export OPERATOR_NAME="mongodb-kubernetes-operator"
+
+# Variables used for release process
+export INITIAL_COMMIT_SHA="9ed5f98fc70c5b3442f633d2393265fb8a2aba0c"
+export INITIAL_VERSION="1.3.0"

scripts/dev/switch_context.sh

@@ -67,7 +67,7 @@ else
   fi
   # Execute the command in a clean environment and capture exported variables
   # Let's use our PATH as a base to have utilities available.
-  current_envs=$(env -i PATH="${PATH}" CURRENT_VARIANT_CONTEXT="${context}" bash -c "${base_command} && export -p")
+  current_envs=$(env -i PWD="${PWD}" PATH="${PATH}" CURRENT_VARIANT_CONTEXT="${context}" bash -c "${base_command} && export -p")
 
   # `export -p` instead of `env` ensures we can safely re-source variables which we rely on further
   # below like our operator.print.env script
@@ -76,7 +76,8 @@ else
 fi
 
 # convert declare -x key=value into key=value
-current_envs=$(echo "${current_envs[@]}" | sed 's/^declare -x //g' | sed 's/=/=/'| sort | uniq)
+# filter out variables that don't have value (missing '=')
+current_envs=$(echo "${current_envs[@]}" | grep '=' | sed 's/^declare -x //g' | sed 's/=/=/'| sort | uniq)
 
 echo -e "## This file is automatically generated by switch_context.sh\n## Do not edit it!" > "${destination_envs_file}.env"
 # shellcheck disable=SC2129