Add ngrok devcontainer feature with amd64 and arm64 support

[Copilot]

The existing public ngrok devcontainer feature is unmaintained and hardcodes amd64, making it unusable on arm64 hosts. This adds a first-party ngrok feature with proper architecture detection.

Changes

• Architecture detection — uses uname -m to map x86_64 → amd64 and aarch64/arm64 → arm64; exits with a clear error for unsupported architectures
• Dynamic download URL — selects the correct ngrok v3 binary from equinox.io based on detected arch; latest maps to the stable channel
• Error handling — curl --fail and explicit tar error checks surface actionable messages instead of silent failures
• Tests — test/ngrok/test.sh, scenarios.json, and install_latest.sh follow the same pattern as existing features
• CI integration — ngrok added to the feature test jobs in .github/workflows/test.yaml, running against debian:latest and ubuntu:latest
• Path-based CI filtering — a compute-feature-matrix precursor job uses dorny/paths-filter@v3 to detect which feature directories (src/<feature>/**, test/<feature>/**) were modified and outputs a JSON features array; test-autogenerated and test-scenarios consume it via fromJson(needs.compute-feature-matrix.outputs.features) so only features with actual changes are tested; workflow_dispatch always runs all features
• Root README — added ngrok to the feature list with architecture notes and a link to its feature README

Usage

{
    "features": {
        "ghcr.io/tokidoki11/devcontainer-feature/ngrok:1": {
            "version": "latest"  // or e.g. "3.5.0"
        }
    }
}

[tokidoki11]

@copilot add test for ngrok feature in github action

[Copilot]

@copilot add test for ngrok feature in github action

Added ngrok to the test-autogenerated and test-scenarios job matrices in .github/workflows/test.yaml (commit c259476). It will now run the same CI test jobs as cargo-lambda and lambroll — autogenerated tests against debian:latest and ubuntu:latest, plus the scenario defined in test/ngrok/scenarios.json.

[tokidoki11]

@copilot fix the test failure

[Copilot]

@copilot fix the test failure

Fixed in commit 2780cec. The test-scenarios (ngrok) job was failing because the devcontainer CLI expects a test script named after each scenario key — install_latest.sh to match the "install_latest" scenario in scenarios.json. Added that file with the same ngrok version / which ngrok checks.

[tokidoki11]

@copilot I want to run check of feature only when feature related item is changed

[Copilot]

@copilot I want to run check of feature only when feature related item is changed

Done in commit 5df5e5d. Added a changes job using dorny/paths-filter@v3 that detects which feature directories were modified. The test-autogenerated and test-scenarios jobs now need: changes and each matrix element has an if condition so only the feature(s) whose src/<feature>/** or test/<feature>/** files actually changed will have their tests run. workflow_dispatch always runs all tests.

[tokidoki11]

@copilot

[Invalid workflow file: .github/workflows/test.yaml#L1](https://github.com/tokidoki11/devcontainer-feature/actions/runs/23940299311/workflow)
(Line: 49, Col: 9): Unrecognized named-value: 'matrix'. Located at position 46 within expression: github.event_name == 'workflow_dispatch' ||
(matrix.features == 'cargo-lambda' && needs.changes.outputs.cargo-lambda == 'true') ||
(matrix.features == 'lambroll' && needs.changes.outputs.lambroll == 'true') ||
(matrix.features == 'ngrok' && needs.changes.outputs.ngrok == 'true'), (Line: 73, Col: 9): Unrecognized named-value: 'matrix'. Located at position 46 within expression: github.event_name == 'workflow_dispatch' ||
(matrix.features == 'cargo-lambda' && needs.changes.outputs.cargo-lambda == 'true') ||
(matrix.features == 'lambroll' && needs.changes.outputs.lambroll == 'true') ||
(matrix.features == 'ngrok' && needs.changes.outputs.ngrok == 'true')

[Copilot]

@copilot

...

Fixed in commit 46af616. The root cause was that GitHub Actions' job-level if cannot reference the matrix context — that's only available inside steps. Resolved by splitting the combined feature+baseImage matrix into separate per-feature jobs (test-autogenerated-cargo-lambda, test-autogenerated-lambroll, test-autogenerated-ngrok, test-scenarios-cargo-lambda, etc.), each with a simple if: needs.changes.outputs.<feature> == 'true' condition that is valid at the job level.

[tokidoki11]

@copilot revert instead
create a precursor job that outputs a JSON string representing the matrix.

also update the readme at the root

[Copilot]

@copilot revert instead
create a precursor job that outputs a JSON string representing the matrix.

...

Done in commit c487746. Reverted the per-feature job split and replaced it with a compute-feature-matrix precursor job that:

1. Runs dorny/paths-filter to detect which feature directories changed
2. Outputs a JSON array string (e.g. ["cargo-lambda","ngrok"]) — or all three features on workflow_dispatch

The test-autogenerated and test-scenarios jobs consume it via fromJson(needs.compute-feature-matrix.outputs.features), which is the correct GitHub Actions pattern for dynamic matrices and avoids the job-level matrix context issue entirely.

Also updated the root README to add ngrok to the feature list.

[tokidoki11]

@copilot that is an ugly if else
Use shell script, create a map variable

[Copilot]

@copilot that is an ugly if else
Use shell script, create a map variable

Done in commit c520aee. Replaced the if/else with a declare -A changed=(...) associative array mapping each feature to its filter output, and an all_features ordered array to iterate in stable order. A single for loop now handles both workflow_dispatch and push/PR cases — no outer branch needed.

[tokidoki11]

@copilot offload that long matrix creation to a shell script inside .github/ and call it inside the action

[Copilot]

@copilot offload that long matrix creation to a shell script inside .github/ and call it inside the action

Done in commit c8cc5d0. Extracted the matrix logic to .github/compute-feature-matrix.sh. It accepts event_name and the per-feature change flags as positional arguments, and writes features=<json> to $GITHUB_OUTPUT. The workflow step is now just:

run: |
  bash .github/compute-feature-matrix.sh \
    "${{ github.event_name }}" \
    "${{ steps.filter.outputs.cargo-lambda }}" \
    "${{ steps.filter.outputs.lambroll }}" \
    "${{ steps.filter.outputs.ngrok }}"