Add new reusable release note generator

Compare to the current script that we are having in all releasing
repositories, this tool:
- Is simpler
- Take custom repo name and repo owner
- Doesn't use os.Exec(), hence doesn't need to run inside the repo
- Doesn't require uptream tag fetching
- Doesn't require, but still supports, GITHUB_TOKEN
- Is more reliable as everything is fetched from github

Signed-off-by: Huy Mai <[email protected]>

hack/release/go.mod

@@ -0,0 +1,11 @@
+module github.com/metal3-io/project-infra/hack/release
+
+go 1.23.2
+
+require (
+	github.com/blang/semver v3.5.1+incompatible
+	github.com/google/go-github v17.0.0+incompatible
+	golang.org/x/oauth2 v0.25.0
+)
+
+require github.com/google/go-querystring v1.1.0 // indirect

hack/release/go.sum

@@ -0,0 +1,12 @@
+github.com/blang/semver v3.5.1+incompatible h1:cQNTCjp13qL8KC3Nbxr/y2Bqb63oX6wdnnjpJbkM4JQ=
+github.com/blang/semver v3.5.1+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
+github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/go-github v17.0.0+incompatible h1:N0LgJ1j65A7kfXrZnUDaYCs/Sf4rEjNlfyDHW9dolSY=
+github.com/google/go-github v17.0.0+incompatible/go.mod h1:zLgOLi98H3fifZn+44m+umXrS52loVEgC2AApnigrVQ=
+github.com/google/go-querystring v1.1.0 h1:AnCroh3fv4ZBgVIf1Iwtovgjaw/GiKJo8M8yD/fhyJ8=
+github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17icRSOU623lUBU=
+golang.org/x/oauth2 v0.25.0 h1:CY4y7XT9v0cRI9oupztF8AgiIu99L/ksR/Xp/6jrZ70=
+golang.org/x/oauth2 v0.25.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

hack/release/main.go

@@ -0,0 +1,219 @@
+//go:build tools
+// +build tools
+
+/*
+Copyright 2025 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 (
+	"context"
+	"fmt"
+  "regexp"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/blang/semver"
+	"github.com/google/go-github/github"
+	"golang.org/x/oauth2"
+)
+
+/*
+This tool prints all the titles of all PRs from previous release to HEAD.
+This needs to be run *before* a tag is created.
+
+Use these as the base of your release notes.
+*/
+
+const (
+	features        = ":sparkles: New Features"
+	bugs            = ":bug: Bug Fixes"
+	documentation   = ":book: Documentation"
+	warning         = ":warning: Breaking Changes"
+	other           = ":seedling: Others"
+	unknown         = ":question: Sort these by hand"
+	superseded      = ":recycle: Superseded or Reverted"
+	warningTemplate = ":rotating_light: This is a %s. Use it only for testing purposes.\nIf you find any bugs, file an [issue](https://github.com/%s/%s/issues/new/).\n\n"
+)
+
+var (
+	outputOrder = []string{
+		warning,
+		features,
+		bugs,
+		documentation,
+		other,
+		unknown,
+		superseded,
+	}
+	releaseTag string
+	repoOwner string
+	repoName string
+	semVersion semver.Version
+	lastReleaseTag string
+)
+
+func main() {
+	releaseTag = os.Getenv("RELEASE_TAG")
+	if releaseTag == "" {
+		log.Fatal("RELEASE_TAG is required")
+	}
+	repoOwner = os.Getenv("REPO_OWNER")
+	if repoOwner == "" {
+		log.Fatal("REPO_OWNER is required")
+	}
+	repoName = os.Getenv("REPO_NAME")
+	if repoName == "" {
+		log.Fatal("REPO_NAME is required")
+	}
+
+	// Create a context
+	ctx := context.Background()
+
+	// Authenticate with GitHub token if available
+	token := os.Getenv("GITHUB_TOKEN")
+	var client *github.Client
+	if token != "" {
+		ts := oauth2.StaticTokenSource(&oauth2.Token{AccessToken: token})
+		tc := oauth2.NewClient(ctx, ts)
+		client = github.NewClient(tc)
+	} else {
+		client = github.NewClient(nil)
+	}
+	releaseName := strings.TrimPrefix(releaseTag, "v")
+	var err error
+	semVersion, err = semver.Make(releaseName)
+	if err != nil {
+		log.Fatalf("Incorrect releaseTag: %v", err)
+	}
+
+	// Get the name of the release branch. Default to "main" if it's a minor release
+	releaseBranch := fmt.Sprintf("release-%d.%d", semVersion.Major, semVersion.Minor)
+	if semVersion.Patch == 0 {
+		releaseBranch = "main"
+	}
+
+	// Get the release tag used for comparison
+	lastVersion := semVersion
+	if lastVersion.Patch == 0 {
+		lastVersion.Minor--
+	} else {
+		lastVersion.Patch--
+	}
+	lastReleaseTag = fmt.Sprintf("v%d.%d.%d", lastVersion.Major, lastVersion.Minor, lastVersion.Patch)
+
+	// Compare commits between the tag and the release branch
+	comparison, _, err := client.Repositories.CompareCommits(ctx, repoOwner, repoName, lastReleaseTag, releaseBranch)
+	if err != nil {
+		log.Fatalf("failed to compare commits: %v", err)
+	}
+	merges := map[string][]string{
+		features:         {},
+		bugs:             {},
+		documentation:    {},
+		warning:          {},
+		other:            {},
+		unknown:          {},
+		superseded:       {},
+	}
+
+	for _, commit := range comparison.Commits {
+		// Only takes the merge commits.
+		if len(commit.Parents) == 1 {
+			continue
+		}
+    mergeCommitRegex := regexp.MustCompile(`Merge pull request #(\d+) from`)
+    matches := mergeCommitRegex.FindStringSubmatch(commit.GetCommit().GetMessage())
+    var prNumber string
+    if len(matches) > 1 {
+      // This is a merge commit, extract the PR number
+      prNumber = matches[1]
+    }
+
+    // Append commit message and PR number
+    lines := strings.Split(commit.GetCommit().GetMessage(), "\n")
+    body := lines[len(lines)-1]
+    if body == "" {
+      continue
+    }
+    var key string
+    switch {
+    case strings.HasPrefix(body, ":sparkles:"), strings.HasPrefix(body, "✨"):
+      key = features
+      body = strings.TrimPrefix(body, ":sparkles:")
+      body = strings.TrimPrefix(body, "✨")
+    case strings.HasPrefix(body, ":bug:"), strings.HasPrefix(body, "🐛"):
+      key = bugs
+      body = strings.TrimPrefix(body, ":bug:")
+      body = strings.TrimPrefix(body, "🐛")
+    case strings.HasPrefix(body, ":book:"), strings.HasPrefix(body, "📖"):
+      key = documentation
+      body = strings.TrimPrefix(body, ":book:")
+      body = strings.TrimPrefix(body, "📖")
+    case strings.HasPrefix(body, ":seedling:"), strings.HasPrefix(body, "🌱"):
+      key = other
+      body = strings.TrimPrefix(body, ":seedling:")
+      body = strings.TrimPrefix(body, "🌱")
+    case strings.HasPrefix(body, ":warning:"), strings.HasPrefix(body, "⚠️"):
+      key = warning
+      body = strings.TrimPrefix(body, ":warning:")
+      body = strings.TrimPrefix(body, "⚠️")
+    case strings.HasPrefix(body, ":rocket:"), strings.HasPrefix(body, "🚀"):
+      continue
+    default:
+      key = unknown
+    }
+    merges[key] = append(merges[key], fmt.Sprintf("- %s (#%d)", body, prNumber))
+	}
+	fmt.Println("<!-- markdownlint-disable no-inline-html line-length -->")
+	// if we're doing beta/rc, print breaking changes and hide the rest of the changes
+	if len(semVersion.Pre) > 0 {
+		switch semVersion.Pre[0].VersionStr {
+		case "beta":
+			fmt.Printf(warningTemplate, "BETA RELEASE", repoOwner, repoName)
+		case "rc":
+			fmt.Printf(warningTemplate, "RELEASE CANDIDATE", repoOwner, repoName)
+		}
+		fmt.Printf("<details>\n")
+		fmt.Printf("<summary>More details about the release</summary>\n\n")
+	}
+	fmt.Printf("# Changes since [%s](https://github.com/%s/%s/tree/%s)\n\n", lastReleaseTag, repoOwner, repoName, lastReleaseTag)
+	// print the changes by category
+	for _, key := range outputOrder {
+		mergeslice := merges[key]
+		if len(mergeslice) > 0 {
+			fmt.Printf("## %v\n\n", key)
+			for _, merge := range mergeslice {
+				fmt.Println(merge)
+			}
+			fmt.Println()
+		}
+	}
+
+	// close the details tag if we had it open, else add the Superseded or Reverted section
+	if len(semVersion.Pre) > 0 {
+		fmt.Printf("</details>\n\n")
+	} else {
+    fmt.Println("\n## :recycle: Superseded or Reverted")
+  }
+
+	fmt.Printf("The container image for this release is: %s\n", releaseTag)
+	if repoName == "cluster-api-provider-metal3" {
+		fmt.Printf("Mariadb image tag is: capm3-%s\n", releaseTag)
+	}
+	fmt.Println("\n_Thanks to all our contributors!_ 😊")
+}