Use charmcraft remote-build for all platforms

[Copilot]

Simplified Implementation: Use charmcraft remote-build for All Platforms

• Revert changes to _charm-quality-checks.yaml (complexity not needed)
• Refactor _charm-release.yaml to use only remote-build
  • Remove runners matrix input
  • Remove platform detection logic
  • Use remote-build for all platforms
  • Add LAUNCHPAD_TOKEN as required secret
  • Simplify to single build job
  • Fix charms output in pack step
  • Set up Launchpad credentials properly with secure permissions
• Code review and security checks completed

Summary

Simplified approach:

• No more matrix builds: Everything uses charmcraft remote-build
• No platform detection: Remote-build handles all platforms defined in charmcraft.yaml
• Cleaner workflow: Single job that builds and releases all platforms
• Two secrets required: CHARMHUB_TOKEN (for publishing) and LAUNCHPAD_TOKEN (for remote-build)
• Secure credential setup: LAUNCHPAD_TOKEN is safely written to ~/.local/share/charmcraft/launchpad-credentials with 600 permissions

This approach is simpler and more maintainable than the previous version.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Use charmcraft remote-build for s390x and ppc64el</issue_title>
<issue_description>Currently, to pack a charm, we take runner name as input,

observability/.github/workflows/_charm-release.yaml

Lines 15 to 21 in c13b2b9

	runners:
	description: |
	Json matrix of the runners to use to build and release the charm.
	Example: ["ubuntu-latest","Ubuntu_ARM64_4C_16G_03"]
	type: string
	required: false
	default: '["ubuntu-latest"]'

and currently the workflow is limited to packing for amd64 and arm64, because those are the runners available from github.

observability/.github/workflows/_charm-release.yaml

Lines 87 to 96 in c13b2b9

	- name: Pack charm(s)
	id: pack
	run: |
	cd "${{ inputs.charm-path }}"
	charmcraft pack -v
	charms="$(basename -a ./*.charm | jq -R -s -c 'split("\n")[:-1]')"
	echo "charms=$charms"
	echo "charms=$charms" >> "$GITHUB_OUTPUT"
	- name: Store charm(s)
	uses: actions/upload-artifact@v4

To pack for s390x and ppc64el, we can use charmcraft remote-build.
Currently, the absence of this blocks:

• Add more platforms grafana-agent-operator#337

In this centralized CI, packing charms for s390x and ppc64el should be done also as part of PR quality checks, but as the last step only after integration tests succeed.

observability/.github/workflows/_charm-quality-checks.yaml

Lines 165 to 166 in c13b2b9

	pack-charm:
	name: Pack the charm

Since charmcraft remote-build does not yet support --build-for, the CI should attempt a remote build only if the .platforms section is not empty after removing arm64 and amd64.

References:

• Do not remote-build amd64, arm64 opentelemetry-collector-snap#50
• Retryable, parallel build grafana-agent-snap#98</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Use charmcraft remote-build for s390x and ppc64el #404

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[sed-i]

@copilot let's simplify things.

[sinapah]

@copilot
Let's make sure we set and use LAUNCHPAD_TOKEN correctly. We need to do echo -e "${LAUNCHPAD_TOKEN}" > ~/.local/share/charmcraft/launchpad-credentials so that we have it in the environment before we attempt to do charmcraft remote-build

[Copilot]

@copilot
Let's make sure we set and use LAUNCHPAD_TOKEN correctly. We need to do echo -e "${LAUNCHPAD_TOKEN}" > ~/.local/share/charmcraft/launchpad-credentials so that we have it in the environmen...

Added Launchpad credentials setup in commits 1642421 and 8474c82. The token is now written to ~/.local/share/charmcraft/launchpad-credentials with secure 600 permissions using printf instead of echo -e for safer handling.

[sed-i]

Reminder.