Add scheduled tasks to run tests with race detection (#2814)

Needs https://github.com/matrix-org/sytest/pull/1308 to be actually
useful.
Not sure if we need to run Sytest in all combinations with enabled race
detection.

Closes https://github.com/matrix-org/dendrite/issues/491

.github/workflows/schedules.yaml

@@ -0,0 +1,128 @@
+name: Scheduled
+
+on:
+  schedule:
+    - cron: '0 0 * * *'  # every day at midnight
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  # run go test with different go versions
+  test:
+    timeout-minutes: 20
+    name: Unit tests (Go ${{ matrix.go }})
+    runs-on: ubuntu-latest
+    # Service containers to run with `container-job`
+    services:
+      # Label used to access the service container
+      postgres:
+        # Docker Hub image
+        image: postgres:13-alpine
+        # Provide the password for postgres
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_DB: dendrite
+        ports:
+          # Maps tcp port 5432 on service container to the host
+          - 5432:5432
+        # Set health checks to wait until postgres has started
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+    strategy:
+      fail-fast: false
+      matrix:
+        go: ["1.18", "1.19"]
+    steps:
+      - uses: actions/checkout@v3
+      - name: Setup go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{ matrix.go }}
+      - uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cache/go-build
+            ~/go/pkg/mod
+          key: ${{ runner.os }}-go${{ matrix.go }}-test-race-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-go${{ matrix.go }}-test-race-
+      - run: go test -race ./...
+        env:
+          POSTGRES_HOST: localhost
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_DB: dendrite
+
+  # Dummy step to gate other tests on without repeating the whole list
+  initial-tests-done:
+    name: Initial tests passed
+    needs: [test]
+    runs-on: ubuntu-latest
+    if: ${{ !cancelled() }} # Run this even if prior jobs were skipped
+    steps:
+      - name: Check initial tests passed
+        uses: re-actors/alls-green@release/v1
+        with:
+          jobs: ${{ toJSON(needs) }}
+
+  # run Sytest in different variations
+  sytest:
+    timeout-minutes: 60
+    needs: initial-tests-done
+    name: "Sytest (${{ matrix.label }})"
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - label: SQLite
+
+          - label: SQLite, full HTTP APIs
+            api: full-http
+
+          - label: PostgreSQL
+            postgres: postgres
+
+          - label: PostgreSQL, full HTTP APIs
+            postgres: postgres
+            api: full-http
+    container:
+      image: matrixdotorg/sytest-dendrite:latest
+      volumes:
+        - ${{ github.workspace }}:/src
+      env:
+        POSTGRES: ${{ matrix.postgres && 1}}
+        API: ${{ matrix.api && 1 }}
+        SYTEST_BRANCH: ${{ github.head_ref }}
+        RACE_DETECTION: 1
+    steps:
+      - uses: actions/checkout@v2
+      - name: Run Sytest
+        run: /bootstrap.sh dendrite
+        working-directory: /src
+      - name: Summarise results.tap
+        if: ${{ always() }}
+        run: /sytest/scripts/tap_to_gha.pl /logs/results.tap
+      - name: Sytest List Maintenance
+        if: ${{ always() }}
+        run: /src/show-expected-fail-tests.sh /logs/results.tap /src/sytest-whitelist /src/sytest-blacklist
+        continue-on-error: true # not fatal
+      - name: Are We Synapse Yet?
+        if: ${{ always() }}
+        run: /src/are-we-synapse-yet.py /logs/results.tap -v
+        continue-on-error: true # not fatal
+      - name: Upload Sytest logs
+        uses: actions/upload-artifact@v2
+        if: ${{ always() }}
+        with:
+          name: Sytest Logs - ${{ job.status }} - (Dendrite, ${{ join(matrix.*, ', ') }})
+          path: |
+            /logs/results.tap
+            /logs/**/*.log*