ci: Combine the Lint and Benchmark workflows so that the benchmark jo…

…b depends on the lint job in one workflow (sourcenetwork#209)

DESCRIPTION:

- Combine the Lint and Benchmark workflows so that the benchmark job depends on the lint job in one workflow.

- The `GOPATH` and `HOME` directory on the custom GitHub runner was not being set be default. Which was giving me: `error: missing $GOPATH` which is a go bug. You can replicate the same bug on your machine by `HOME='' GOPATH='' go test ./..`

- Set HOME for GO stuff to parent directory where our runner checks out our code. i.e. `/actions-runner/_work`

.github/workflows/lint-then-benchmark.yml

@@ -0,0 +1,155 @@
+name: Lint and then Benchmark
+
+
+on:
+  pull_request:
+
+  push:
+    tags:
+      - v*
+    branches:
+      - master
+      - develop
+
+
+## These are the permissions for the lint check job.
+permissions:
+  # Allow read access to pull request (Required for the `only-new-issues` option.)
+  pull-requests: read
+  contents: read
+
+
+jobs:
+
+
+  # ========================================================= Step-1: Run the lint check.
+  golangci:
+    name: Lint Check
+    strategy:
+      matrix:
+        go-version: [1.17.5]
+        os: [ubuntu-latest]
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Check out code into the directory
+        uses: actions/checkout@v2
+
+      - name: Run the golangci-lint
+        uses: golangci/golangci-lint-action@v2
+
+        with:
+          # Required: the version of golangci-lint is required.
+          # Note: The version should not pick the patch version as the latest patch
+          #  version is what will always be used.
+          version: v1.43
+
+          # Optional: working directory, useful for monorepos or if we wanted to run this
+          #  on a non-root directory.
+          # working-directory: ./
+
+          # Optional: golangci-lint command line arguments.
+          # Note: we can set `--issues-exit-code=0` if we want a successcode always,
+          #  indicating that the linter ran successfully (weather or not linter errors
+          #  exist or not doesn't matter). But the good think is that the annotations
+          #  will still show up. I think this can be useful if we don't want the pipeline
+          #  to stop just because we had some linter errors. 
+          args: --issues-exit-code=1 --config .golangci.sourceinc.yaml
+
+          # Optional: we can set the below to `true` if we only want to see newly
+          #  introduced linter errors, however I found that in practive that option is a
+          #  bit gimmicky, as it passes the linter check despite having new linter errors
+          #  in some cases. So we opt in for all annotations of linter errors to show up,
+          #  this is actually nicer because we suppress our linter errors manually
+          #  anyways so there shouldn't be any linter errors anyways. The enforces us to
+          #  always have a clean lint state.
+          only-new-issues: false
+
+
+  # ================== Step-2: Start the runner and get it registered as a github runner.
+  start-runner:
+    name: Start self-hosted EC2 runner
+    needs: golangci # only run if the linter check passed
+    runs-on: ubuntu-latest
+    outputs:
+      label: ${{ steps.start-ec2-runner.outputs.label }}
+      ec2-instance-id: ${{ steps.start-ec2-runner.outputs.ec2-instance-id }}
+
+    steps:
+
+      - name: Configure AWS credentials
+        uses: aws-actions/configure-aws-credentials@v1
+        with:
+          aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
+          aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+          aws-region: ${{ secrets.AWS_REGION }}
+
+      - name: Start EC2 runner
+        id: start-ec2-runner
+        uses: machulav/ec2-github-runner@v2
+        with:
+          mode: start
+          github-token: ${{ secrets.REPO_SCOPE_PAT }}
+          ec2-image-id: ${{ secrets.EC2_IMAGE_ID }}
+          ec2-instance-type: t3.xlarge
+          subnet-id: ${{ secrets.SUBNET_ID }}
+          security-group-id: ${{ secrets.SECURITY_GROUP_ID }}
+          ## iam-role-name: my-role-name # optional, requires additional permissions
+          ## aws-resource-tags: > # optional, requires additional permissions
+          ##   [
+          ##     {"Key": "Name", "Value": "ec2-github-runner"},
+          ##     {"Key": "GitHubRepository", "Value": "${{ github.repository }}"}
+          ##   ]
+
+
+  # ============================Step-3: Run the benchmarks on the runner we just started.
+  benchmark-ec2-runner:
+    name: Run the benchmarks on the started EC2 runner
+    needs:
+      - golangci # only run if the linter check passed.
+      - start-runner # required to start the main job when the runner is ready
+    runs-on: ${{ needs.start-runner.outputs.label }} # run the job on the newly created runner
+
+    env:
+      # This is also the same directory as `$GITHUB_WORKSPACE/..`
+      HOME: /actions-runner/_work
+      GOPATH: /actions-runner/_work/go
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Start Running the bechmarks
+        run: make test:bench
+
+
+  # =============================== Step-4: Stop the runner once the benchmarks have ran.
+  stop-runner:
+    name: Stop self-hosted EC2 runner
+    needs:
+      - golangci # only run if the linter check passed.
+      - start-runner # required to get output from the start-runner job
+      - benchmark-ec2-runner # required to wait when the main job is done
+    runs-on: ubuntu-latest
+
+    # Stop the runner even if an error happened in the previous jobs. Also ensure that
+    #  if the EC2 runner was actually started, only then we stop it.
+    if: ${{ always() && (needs.start-runner.result == 'success') }} 
+
+    steps:
+
+      - name: Configure AWS credentials
+        uses: aws-actions/configure-aws-credentials@v1
+        with:
+          aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
+          aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+          aws-region: ${{ secrets.AWS_REGION }}
+
+      - name: Stop EC2 runner
+        uses: machulav/ec2-github-runner@v2
+        with:
+          mode: stop
+          github-token: ${{ secrets.REPO_SCOPE_PAT }}
+          label: ${{ needs.start-runner.outputs.label }}
+          ec2-instance-id: ${{ needs.start-runner.outputs.ec2-instance-id }}