feat: add gas-comparison PR bot (#173)

* feat: add gas-comparison PR bot

* chore: changelog

.github/workflows/gas_reports.yml

@@ -0,0 +1,44 @@
+name: Compare Snapshot
+
+on:
+  pull_request:
+    paths:
+      - "scripts/compare_snapshot.py"
+
+jobs:
+  compare-snapshot:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.x" # Specify the Python version required
+
+      - name: Set up Scarb
+        uses: software-mansion/setup-scarb@v1
+        with:
+          scarb-version: "nightly-2023-08-12"
+
+      - name: Run compare_snapshot script
+        id: run-script
+        env:
+          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
+        run: |
+          result=$(python scripts/compare_snapshot.py)
+          result=$(echo "$result" | tail -n +3) # Strip the first two lines
+          result="${result//'%'/'%25'}"
+          result="${result//$'\n'/'%0A'}"
+          result="${result//$'\r'/'%0D'}"
+          echo "::set-output name=result::${result}"
+
+      - name: Comment on PR
+        uses: thollander/actions-comment-pull-request@v2
+        with:
+          message: "Snapshot Comparison Report:\n\n${{
+            steps.run-script.outputs.result }}" # Access the result output variable
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          comment_tag: gas-report

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to
 
 ### Added
 
+- tooling: PR bot displays gas changes induced by PR 
 - refactor(22/08/2023): refactor project to use scarb workspace
 - opcode(22/08/2023): add 0x1A-BYTE opcode
 - tooling: CI now generates gas snapshots artifacts. pre-push hook to compare

scripts/compare_snapshot.py

@@ -19,25 +19,23 @@ def get_github_token_from_env(file_path=".env"):
                 if key == "GITHUB_TOKEN":
                     return value
     except FileNotFoundError:
-        print(f"Error: {file_path} file not found.")
+        return None
     except ValueError:
         print(f"Error: Invalid format in {file_path}. Expected 'KEY=VALUE' format.")
     return None
 
 def get_previous_snapshot():
-    REPO = "enitrat/kakarot-ssj"  # Replace with your GitHub username and repo name
-    GITHUB_TOKEN = get_github_token_from_env()
+    REPO = "kkrt-labs/kakarot-ssj"  # Replace with your GitHub username and repo name
+    GITHUB_TOKEN = get_github_token_from_env() or os.environ.get("GITHUB_TOKEN")
 
     try:
-        REPO = "kkrt-labs/kakarot-ssj"
-
         # Fetch the list of workflow runs
         cmd = f"curl -s -H 'Authorization: token {GITHUB_TOKEN}' -H 'Accept: application/vnd.github.v3+json' 'https://api.github.com/repos/{REPO}/actions/runs'"
         result = subprocess.check_output(cmd, shell=True)
         runs = json.loads(result)
 
         # Find the latest successful run
-        latest_successful_run = next(run for run in runs["workflow_runs"] if run["conclusion"] == "success")
+        latest_successful_run = next(run for run in runs["workflow_runs"] if (run["conclusion"] == "success" and run["head_branch"] == "main"))
 
         # Fetch the artifacts for that run
         run_id = latest_successful_run["id"]
@@ -118,6 +116,8 @@ def print_colored_output(improvements, worsened, gas_changes):
         color = RED if gas_changes > 0 else GREEN
         gas_statement = "performance degradation, gas consumption +" if gas_changes > 0 else "performance improvement, gas consumption"
         print(color + f"Overall gas change: {gas_statement}{format(gas_changes, '.2f')} %" + ENDC)
+    else:
+        print("No changes in gas consumption.")
 
 def total_gas_used(current,previous):
     """Return the total gas used in the current and previous snapshot."""