Add auto merge tooling

PL-133248

Author: leona-ya

.github/workflows/auto-merge.yaml

@@ -0,0 +1,44 @@
+name: auto-merge
+
+on:
+  workflow_dispatch: {}
+  schedule:
+    - cron: "5 12-23 * * MON-FRI"
+
+jobs:
+  run-auto-merge:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cachix/install-nix-action@v21
+      - uses: actions/create-github-app-token@v1
+        id: app-token
+        with:
+          app-id: ${{ vars.AUTO_MERGE_APP_ID }}
+          private-key: ${{ secrets.AUTO_MERGE_APP_PRIVATE_KEY }}
+          owner: ${{ github.repository_owner }}
+      - run: |
+          echo "::add-mask::${{steps.app-token.outputs.token}}"
+      - name: Get GitHub App User ID
+        id: get-user-id
+        run: echo "user-id=$(gh api "/users/${{ steps.app-token.outputs.app-slug }}[bot]" --jq .id)" >> "$GITHUB_OUTPUT"
+        env:
+          GH_TOKEN: ${{ steps.app-token.outputs.token }}
+      - run: |
+          git config --global user.name '${{ steps.app-token.outputs.app-slug }}[bot]'
+          git config --global user.email '${{ steps.get-user-id.outputs.user-id }}+${{ steps.app-token.outputs.app-slug }}[bot]@users.noreply.github.com>'
+      - name: build release tooling
+        run: |
+          nix build .#
+      - name: run merge tool
+        run: |
+          ./result/bin/auto-merge merge --action-run-repo-name ${{ github.repository }} --fc-nixos-dir fc-nixos
+        env:
+          GH_TOKEN: ${{ steps.app-token.outputs.token }}
+          MATRIX_HOOKSHOT_URL: ${{ secrets.MATRIX_HOOKSHOT_URL }}
+          MONITORING_REVIEW_URL: ""
+      - uses: actions/upload-artifact@v4
+        with:
+          name: status-json
+          path: auto-merge-status.json
+          if-no-files-found: error

auto-merge-config.toml

@@ -0,0 +1,36 @@
+[general]
+# 0 = Monday, 6 = Sunday
+production_merge_day = 3
+# Times are in Europe/Berlin
+production_merge_cutoff_hour = 12
+platform_versions = [ "24.05" ]
+fc_nixos_repo_name = "flyingcircusio/fc-nixos-testing"
+
+[monitoring_review]
+# Names of monitoring review columns
+name = "platform-dev"
+notification_cutoff_hour = 15
+
+# Weekdays relative to the production_merge_day
+# 0 = production_merge_day, 1 = production_merge_day + 1
+# e.g. production_merge_day = Thursday. pr_merge_days.0 = THU, pr_merge_days.1=FRI, pr_merge_days.2=MON
+[pr_merge_days]
+[pr_merge_days.0]
+max_risk = 5
+min_urgency = 1
+
+[pr_merge_days.1]
+max_risk = 4
+min_urgency = 1
+
+[pr_merge_days.2]
+max_risk = 3
+min_urgency = 2
+
+[pr_merge_days.3]
+max_risk = 2
+min_urgency = 3
+
+[pr_merge_days.4]
+max_risk = 1
+min_urgency = 5

flake.nix

@@ -16,9 +16,17 @@
           src = ./.;
           pyproject = true;
           build-system = [ pypkgs.setuptools-scm ];
+          nativeCheckInputs = [
+            pypkgs.pytestCheckHook
+          ];
           dependencies = [
+            pypkgs.python-dateutil
+            pypkgs.gql
+            pypkgs.gql.optional-dependencies.requests
+            pypkgs.pydantic
             pypkgs.setuptools
             pypkgs.gitpython
+            pypkgs.requests
             pypkgs.pygithub
             pypkgs.rich
             pkgs.gh

pyproject.toml

@@ -14,12 +14,22 @@ name = "fc-nixos-release-tools"
 dynamic = ["version"]
 requires-python = ">= 3.11"
 dependencies = [
-    "pygithub~=2.5",
-    "gitpython~=3.1",
-    "requests~=2.32.2",
-    "rich~=13.8.1"
+    "pygithub>=2.5",
+    "gitpython>=3.1",
+    "requests>=2.32",
+    "rich>=13.8",
+    "gql[requests]~=3.5",
+    "pydantic>=2.9",
+    "pygithub>=2.5",
+    "python-dateutil>=2.9"
+]
+
+[project.optional-dependencies]
+dev = [
+  "pytest>=7.4"
 ]
 
 [project.scripts]
 release = "release:main"
 update-nixpkgs = "update_nixpkgs:main"
+auto-merge = "auto_merge:main"

src/__init__.py

@@ -0,0 +1,70 @@
+import argparse
+import logging
+import os
+import sys
+
+from auto_merge import check_pr, merge
+from auto_merge.config import load_config
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.set_defaults(func="print_usage")
+    subparsers = parser.add_subparsers(help="subcommand help")
+
+    parser_check_pr = subparsers.add_parser("check-pr", help="check-pr help")
+    parser_check_pr.add_argument(
+        "pr_id", type=int, help="ID of the pull request, we want to consider"
+    )
+    parser_check_pr.set_defaults(func=check_pr.check_pr)
+
+    parser_merge = subparsers.add_parser("merge", help="merge help")
+    parser_merge.add_argument(
+        "--action-run-repo-name",
+        type=str,
+        help="Repository name including owner, e.g. flyingcircusio/fc-nixos-release-tooling containing this workflow",
+        required=True,
+        default="",
+    )
+    parser_merge.add_argument(
+        "--fc-nixos-dir",
+        help="Directory where the fc-nixos git checkout is in",
+        required=True,
+    )
+    parser_merge.set_defaults(func=merge.run)
+
+    args = parser.parse_args()
+    func = args.func
+    if func == "print_usage":
+        parser.print_usage()
+        sys.exit(1)
+
+    kwargs = dict(args._get_kwargs())
+    del kwargs["func"]
+    kwargs["config"] = load_config()
+    try:
+        kwargs["github_access_token"] = os.environ["GH_TOKEN"]
+    except KeyError:
+        raise Exception("Missing `GH_TOKEN` environment variable.")
+    if func == merge.run:
+        try:
+            kwargs["monitoring_review_url"] = os.environ[
+                "MONITORING_REVIEW_URL"
+            ]
+        except KeyError:
+            raise Exception(
+                "Missing `MONITORING_REVIEW_URL` environment variable."
+            )
+        try:
+            kwargs["matrix_hookshot_url"] = os.environ["MATRIX_HOOKSHOT_URL"]
+        except KeyError:
+            raise Exception(
+                "Missing `MATRIX_HOOKSHOT_URL` environment variable."
+            )
+
+    logging.basicConfig(level=logging.INFO)
+    func(**kwargs)
+
+
+if __name__ == "__main__":
+    main()

src/auto_merge/__init__.py

@@ -0,0 +1,28 @@
+from github import Auth, Github
+
+from auto_merge import utils
+from auto_merge.config import Config
+
+
+def check_pr(pr_id: int, github_access_token: str, config: Config):
+    gh = Github(auth=Auth.Token(github_access_token))
+    repository = gh.get_repo(config.general.fc_nixos_repo_name)
+
+    pr = repository.get_pull(pr_id)
+    risk, urgency = utils.get_label_values_for_pr(pr.labels)
+    if risk is None or urgency is None:
+        # This raises a runtime error, so it shows as a red check indicator in GitHub
+        raise RuntimeError(
+            "PR doesn't have risk and urgency labels. Not mergeable."
+        )
+    # check if PR is approved
+    mergeable = utils.check_pr_mergeable(
+        repository, pr, github_access_token, config
+    )
+    if mergeable:
+        merge_date = utils.calculate_merge_date(risk, urgency, config)
+        msg = f"This PR is ready to merge. Merge scheduled for {merge_date.isoformat()}"
+        for comment in pr.get_issue_comments():
+            if comment.body == msg:
+                return
+        pr.create_issue_comment(msg)

src/auto_merge/check_pr.py

@@ -0,0 +1,33 @@
+import tomllib
+
+from pydantic import BaseModel
+
+
+class PRMergeDayConfig(BaseModel):
+    max_risk: int
+    min_urgency: int
+
+
+class GeneralConfig(BaseModel):
+    # Our days are virtual to the production merge day and cutoff hour
+    production_merge_day: int
+    production_merge_cutoff_hour: int
+    fc_nixos_repo_name: str
+    platform_versions: list[str]
+
+
+class MonitoringReviewConfig(BaseModel):
+    name: str
+    notification_cutoff_hour: int
+
+
+class Config(BaseModel):
+    pr_merge_days: dict[int, PRMergeDayConfig]
+    general: GeneralConfig
+    monitoring_review: MonitoringReviewConfig
+
+
+def load_config() -> Config:
+    with open("auto-merge-config.toml", "rb") as f:
+        data = tomllib.load(f)
+        return Config.model_validate(data)