Add CI pipeline #1

	name: Build Postgres Replica Image

	on:
	pull_request:
	paths:
	- 'postgres_replica.dockerfile'

	jobs:
	export_variables:
	runs-on: ubuntu-latest

	outputs:
	replica_image: ${{ steps.compute_container_registry_name.outputs.CR_NAME }}/postgres_replica:${{ steps.calculate_replica_sha.outputs.REPLICA_SHA }}

	steps:
	- name: Checkout repository
	uses: actions/checkout@v4

	- name: Compute container registry name
	id: compute_container_registry_name
	run: echo "CR_NAME=$(echo ghcr.io/${{ github.repository }} \| tr '[:upper:]' '[:lower:]')" >> $GITHUB_OUTPUT

	- name: Calculate SHA256 for postgres_replica.dockerfile
	id: calculate_replica_sha
	run: echo "REPLICA_SHA=$(sha256sum postgres_replica.dockerfile \| awk '{ print substr($1, 1, 12) }')" >> $GITHUB_OUTPUT

	prebuild_replica:
	needs: export_variables
	runs-on: ubuntu-latest

	steps:
	- name: Checkout repository
	uses: actions/checkout@v4

	- name: Log in to GitHub Container Registry
	uses: docker/login-action@v2
	with:
	registry: ghcr.io
	username: ${{ github.actor }}
	password: ${{ secrets.GITHUB_TOKEN }}

	- name: Build and tag replica Docker image
	run: docker build -f postgres_replica.dockerfile -t ${{ needs.export_variables.outputs.replica_image }} .

	- name: Push replica Docker image
	run: docker push ${{ needs.export_variables.outputs.replica_image }}

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