Add PR Verifier action

This adds a github action that verifies PR titles according to the
release notes rules, and verifies a couple of basic PR descriptiveness
checks.  It's automatically run on this repository.

.github/workflows/main.yml

@@ -0,0 +1,16 @@
+on:
+  pull_request_target:
+    types: [opened, edited, reopened]
+
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+    name: verify PR contents
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Verifier action
+      id: verifier
+      uses: ./
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}

Dockerfile

@@ -0,0 +1,15 @@
+FROM golang:1.15 as build
+
+WORKDIR /go/src/verify
+COPY verify verify
+COPY notes notes
+WORKDIR /go/src/verify/verify
+
+ENV CGO_ENABLED=0
+RUN go build -o /go/bin/verifypr ./cmd/
+
+FROM gcr.io/distroless/static-debian10
+
+COPY --from=build /go/bin/verifypr /verifypr
+
+ENTRYPOINT ["/verifypr"]

action.yml

@@ -0,0 +1,9 @@
+name: 'Verify KubeBuilder PRs'
+description: 'Verify PRs for the KubeBuilder project repos & similar'
+inputs:
+  github_token:
+    description: "the github_token provided by the actions runner"
+    required: true
+runs:
+  using: docker
+  image: 'Dockerfile'

notes/common/prefix.go

@@ -17,10 +17,47 @@ limitations under the License.
 package common
 
 import (
+	"fmt"
 	"strings"
 )
 
 type PRType int
+func (t PRType) Emoji() string {
+	switch t {
+	case UncategorizedPR:
+		return "<uncategorized>"
+	case BreakingPR:
+		return emojiBreaking
+	case FeaturePR:
+		return emojiFeature
+	case BugfixPR:
+		return emojiBugfix
+	case DocsPR:
+		return emojiDocs
+	case InfraPR:
+		return emojiInfra
+	default:
+		panic(fmt.Sprintf("unrecognized PR type %v", t))
+	}
+}
+func (t PRType) String() string {
+	switch t {
+	case UncategorizedPR:
+		return "uncategorized"
+	case BreakingPR:
+		return "breaking"
+	case FeaturePR:
+		return "feature"
+	case BugfixPR:
+		return "bugfix"
+	case DocsPR:
+		return "docs"
+	case InfraPR:
+		return "infra"
+	default:
+		panic(fmt.Sprintf("unrecognized PR type %v", t))
+	}
+}
 
 const (
 	UncategorizedPR PRType = iota

notes/verify/title.go

@@ -0,0 +1,60 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package verify
+
+import (
+	"fmt"
+
+	"sigs.k8s.io/kubebuilder-release-tools/notes/common"
+)
+
+type prTitleError struct {
+	title string
+}
+func (e *prTitleError) Error() string {
+	return "no matching PR type indicator found in title"
+}
+func (e *prTitleError) Help() string {
+	return fmt.Sprintf(
+`I saw a title of %[2]s%[1]s%[2]s, which doesn't seem to have any of the acceptable prefixes.
+
+You need to have one of these as the prefix of your PR title:
+
+- Breaking change: ⚠ (%[2]s:warning:%[2]s)
+- Non-breaking feature: ✨ (%[2]s:sparkles:%[2]s)
+- Patch fix: 🐛 (%[2]s:bug:%[2]s)
+- Docs: 📖 (%[2]s:book:%[2]s)
+- Infra/Tests/Other: 🌱 (%[2]s:seedling:%[2]s)
+
+More details can be found at [sigs.k8s.io/controller-runtime/VERSIONING.md](https://sigs.k8s.io/controller-runtime/VERSIONING.md).`, e.title, "`")
+}
+
+// VerifyPRTitle checks that the PR title matches a valid PR type prefix,
+// returning a message describing what was found on success, and a special
+// error (with more detailed help via .Help) on failure.
+func VerifyPRTitle(title string) (string, error) {
+	prType, finalTitle := common.PRTypeFromTitle(title)
+	if prType == common.UncategorizedPR {
+		return "", &prTitleError{title: title}
+	}
+
+	return fmt.Sprintf(
+`Found %s PR (%s) with final title:
+
+	%s
+`, prType.Emoji(), prType, finalTitle), nil
+}

verify/cmd/runner.go

@@ -0,0 +1,105 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"fmt"
+	"strings"
+	"regexp"
+
+	"github.com/google/go-github/v32/github"
+
+	notes "sigs.k8s.io/kubebuilder-release-tools/notes/common"
+	notesver "sigs.k8s.io/kubebuilder-release-tools/notes/verify"
+	"sigs.k8s.io/kubebuilder-release-tools/verify"
+)
+
+type prErrs struct {
+	errs []string
+}
+func (e prErrs) Error() string {
+	return fmt.Sprintf("%d issues found with your PR description", len(e.errs))
+}
+func (e prErrs) Help() string {
+	res := make([]string, len(e.errs))
+	for _, err := range e.errs {
+		parts := strings.Split(err, "\n")
+		for i, part := range parts[1:] {
+			parts[i+1] = "  "+part
+		}
+		res = append(res, "- "+strings.Join(parts, "\n"))
+	}
+	return strings.Join(res, "\n")
+}
+
+func main() {
+	verify.ActionsEntrypoint(verify.RunPlugins(
+		verify.PRPlugin{
+			Name: "PR Type",
+			Title: "PR Type in Title",
+			ProcessPR: func(pr *github.PullRequest) (string, error) {
+				return notesver.VerifyPRTitle(pr.GetTitle())
+			},
+			ForAction: func(action string) bool {
+				switch action {
+				case "opened", "edited", "reopened":
+					return true
+				default:
+					return false
+				}
+			},
+		},
+
+		verify.PRPlugin{
+			Name: "PR Desc",
+			Title: "Basic PR Descriptiveness Check",
+			ProcessPR: func(pr *github.PullRequest) (string, error) {
+				var errs []string
+				// TODO(directxman12): add warnings when we have them
+
+				lineCnt := 0
+				for _, line := range strings.Split(pr.GetBody(), "\n") {
+					if strings.TrimSpace(line) == "" {
+						continue
+					}
+					lineCnt++
+				}
+				if lineCnt < 2 {
+					errs = append(errs, "**your PR body is *really* short**.\n\nIt probably isn't descriptive enough.\nYou should give a description that highlights both what you're doing it and *why* you're doing it. Someone reading the PR description without clicking any issue links should be able to roughly understand what's going on")
+				}
+
+				_, title := notes.PRTypeFromTitle(pr.GetTitle())
+				if regexp.MustCompile(`#\d{1,}\b`).MatchString(title) {
+					errs = append(errs, "**Your PR has an issue number in the title.**\n\nThe title should just be descriptive.\nIssue numbers belong in the PR body as either `Fixes #XYZ` (if it closes the issue or PR), or something like `Related to #XYZ` (if it's just related).")
+				}
+
+				if len(errs) == 0 {
+					return "Your PR description looks okay!", nil
+				}
+				return "", prErrs{errs: errs}
+			},
+			ForAction: func(action string) bool {
+				switch action {
+				case "opened", "edited", "reopened":
+					return true
+				default:
+					return false
+				}
+			},
+		},
+	))
+}