ci: remove the CI jobs garnix now runs as flake checks

Garnix builds every flake check and package directly, so the GitHub
Actions wrappers around them are redundant:

  - nix-checks       checks.{build,gotest,golangci-lint,formatting}
  - nix-module-test  checks.headscale (NixOS module test)
  - test-integration the integration-* NixOS-VM check matrix
  - build            packages.headscale (nix build)

Kept are the pipelines garnix cannot reproduce: servertest (excluded
from the flake), integration-legacy (needs real DERP, so it cannot run
hermetically), and the check-generated / check-tests generators that
keep the nix integration matrix and protobuf output in sync.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WxukxKem3HU4i5CqNrvvdj

.github/workflows/build.yml

@@ -1,95 +0,0 @@
-name: Build
-
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-
-concurrency:
-  group: ${{ github.workflow }}-$${{ github.head_ref || github.run_id }}
-  cancel-in-progress: true
-
-defaults:
-  run:
-    shell: nix develop --fallback --command bash -e {0}
-
-jobs:
-  build-nix:
-    runs-on: ubuntu-latest
-    permissions: write-all
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-        with:
-          fetch-depth: 2
-      - name: Get changed files
-        id: changed-files
-        uses: dorny/paths-filter@de90cc6fb38fc0963ad72b210f1f284cd68cea36 # v3.0.2
-        with:
-          filters: |
-            files:
-              - '*.nix'
-              - 'go.*'
-              - '**/*.go'
-              - 'integration_test/'
-              - 'config-example.yaml'
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-        if: steps.changed-files.outputs.files == 'true'
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-        if: steps.changed-files.outputs.files == 'true'
-
-      - name: Check vendor hash
-        id: vendorhash
-        if: steps.changed-files.outputs.files == 'true'
-        run: |
-          go run ./cmd/vendorhash check | tee check-result
-          {
-            grep '^expected_sri=' check-result || true
-            grep '^actual_sri='   check-result || true
-          } >> "$GITHUB_OUTPUT"
-
-      - name: Vendor hash diverging
-        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
-        if: failure() && steps.vendorhash.outcome == 'failure'
-        with:
-          github-token: ${{secrets.GITHUB_TOKEN}}
-          script: |
-            github.rest.pulls.createReviewComment({
-              pull_number: context.issue.number,
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              body: 'Vendor hash in `flakehashes.json` is stale (was `${{ steps.vendorhash.outputs.expected_sri }}`, should be `${{ steps.vendorhash.outputs.actual_sri }}`). Run `go run ./cmd/vendorhash update` and commit the result.'
-            })
-
-      - name: Run nix build
-        if: steps.changed-files.outputs.files == 'true'
-        run: nix build --fallback
-
-      - uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
-        if: steps.changed-files.outputs.files == 'true'
-        with:
-          name: headscale-linux
-          path: result/bin/headscale
-  build-cross:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        env:
-          - "GOARCH=arm64 GOOS=linux"
-          - "GOARCH=amd64 GOOS=linux"
-          - "GOARCH=arm64 GOOS=darwin"
-          - "GOARCH=amd64 GOOS=darwin"
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-
-      - name: Run go cross compile
-        env:
-          CGO_ENABLED: 0
-        run: env ${{ matrix.env }} go build -o "headscale"
-          ./cmd/headscale
-      - uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
-        with:
-          name: "headscale-${{ matrix.env }}"
-          path: "headscale"

.github/workflows/nix-checks.yml

@@ -1,56 +0,0 @@
-name: Nix Flake Checks
-
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-    branches:
-      - main
-
-concurrency:
-  group: ${{ github.workflow }}-$${{ github.head_ref || github.run_id }}
-  cancel-in-progress: true
-
-# Each job only runs `nix build .#checks.<system>.<name>`; the check logic lives
-# in flake.nix via the flake-checks library. The fileset-filtered checks hit the
-# hestia cache when their inputs are unchanged, so no changed-files gating.
-permissions:
-  contents: read
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-      - name: build
-        run: nix build -L .#checks.x86_64-linux.build
-
-  gotest:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-      - name: gotest
-        run: nix build -L .#checks.x86_64-linux.gotest
-
-  golangci-lint:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-      - name: golangci-lint
-        run: nix build -L .#checks.x86_64-linux.golangci-lint
-
-  formatting:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-      - name: formatting
-        run: nix build -L .#checks.x86_64-linux.formatting

.github/workflows/nix-module-test.yml

@@ -1,51 +0,0 @@
-name: NixOS Module Tests
-
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-    branches:
-      - main
-
-concurrency:
-  group: ${{ github.workflow }}-$${{ github.head_ref || github.run_id }}
-  cancel-in-progress: true
-
-jobs:
-  nix-module-check:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-        with:
-          fetch-depth: 2
-
-      - name: Get changed files
-        id: changed-files
-        uses: dorny/paths-filter@de90cc6fb38fc0963ad72b210f1f284cd68cea36 # v3.0.2
-        with:
-          filters: |
-            nix:
-              - 'nix/**'
-              - 'flake.nix'
-              - 'flake.lock'
-            go:
-              - 'go.*'
-              - '**/*.go'
-              - 'cmd/**'
-              - 'hscontrol/**'
-
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-        if: steps.changed-files.outputs.nix == 'true' || steps.changed-files.outputs.go == 'true'
-
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-        if: steps.changed-files.outputs.nix == 'true' || steps.changed-files.outputs.go == 'true'
-
-      - name: Run NixOS module tests
-        if: steps.changed-files.outputs.nix == 'true' || steps.changed-files.outputs.go == 'true'
-        run: |
-          echo "Running NixOS module integration test..."
-          nix build .#checks.x86_64-linux.headscale -L --fallback

.github/workflows/test-integration.yaml

@@ -1,55 +0,0 @@
-name: integration
-
-on:
-  pull_request:
-    branches:
-      - main
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
-  cancel-in-progress: true
-
-permissions:
-  contents: read
-
-# Each test is a NixOS-VM flake check (full tailscale version matrix, sqlite
-# plus a postgres variant) — one job per check, derived from the checks the
-# flake exposes. The fileset-filtered, content-addressed checks hit the hestia
-# cache when their inputs are unchanged. A prime job builds the shared images +
-# test binary once so the matrix substitutes them instead of each rebuilding.
-jobs:
-  list:
-    runs-on: ubuntu-latest
-    outputs:
-      checks: ${{ steps.list.outputs.checks }}
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-      - id: list
-        run: |
-          checks=$(nix eval --json .#checks.x86_64-linux --apply builtins.attrNames \
-            | jq -c '[.[] | select(startswith("integration-"))]')
-          echo "checks=$checks" >> "$GITHUB_OUTPUT"
-
-  prime:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-      - run: nix build -L --fallback .#packages.x86_64-linux.integration-deps
-
-  integration:
-    needs: [list, prime]
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        check: ${{ fromJson(needs.list.outputs.checks) }}
-    steps:
-      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-      - uses: NixOS/nix-installer-action@6b8548fe06acfb0155a50ab5d561accb215764cc # main
-      - uses: Mic92/hestia/action@ff07bb902a9968ac0c3d0e51d90a606662a375d8 # main
-      - name: ${{ matrix.check }}
-        run: nix build -L --fallback .#checks.x86_64-linux.${{ matrix.check }}

integration/README.md

@@ -21,16 +21,19 @@ go run ./cmd/hi doctor
 go run ./cmd/hi run "TestPingAllByIP"
 ```
 
-Alternatively, [`act`](https://github.com/nektos/act) runs the GitHub
-Actions workflow locally:
+In CI each test also runs as its own hermetic NixOS-VM flake check. Run
+one locally exactly the way CI does:
 
 ```bash
-act pull_request -W .github/workflows/test-integration.yaml
+nix build .#checks.x86_64-linux.integration-TestPingAllByIP
 ```
 
-Each test runs as a separate workflow on GitHub Actions. To add a new
-test, run `go generate` inside `../cmd/gh-action-integration-generator/`
-and commit the generated workflow file.
+The check matrix is generated: after adding or renaming a test, run `go
+generate` in `.github/workflows/` to refresh `integration/tests.nix`,
+`integration/postgres-tests.nix`, and `integration/excluded-tests.json`,
+then commit the result. Tests that need the public internet (real DERP)
+cannot run hermetically; they are listed in `excluded-tests.json` and
+run via the `integration-legacy` workflow instead.
 
 ## Framework overview