tools: Add gerrit-stats

Gives you juicy stats for contributions to the project.

Change-Id: I4f3e7f03cc43947675e916a8036317af4a894d12
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/57883
Auto-Submit: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: David Neto <dneto@google.com>

tools/src/cmd/gerrit-stats/main.go

@@ -0,0 +1,198 @@
+// Copyright 2021 The Tint 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.
+
+// gerrit-stats gathers statistics about changes made to Tint.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"os"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/andygrunwald/go-gerrit"
+)
+
+const (
+	yyyymmdd  = "2006-01-02"
+	gerritURL = "https://dawn-review.googlesource.com/"
+)
+
+var (
+	// See https://dawn-review.googlesource.com/new-password for obtaining
+	// username and password for gerrit.
+	gerritUser  = flag.String("gerrit-user", "", "gerrit authentication username")
+	gerritPass  = flag.String("gerrit-pass", "", "gerrit authentication password")
+	repoFlag    = flag.String("repo", "tint", "the project (tint or dawn)")
+	userFlag    = flag.String("user", "", "user name / email")
+	afterFlag   = flag.String("after", "", "start date")
+	beforeFlag  = flag.String("before", "", "end date")
+	daysFlag    = flag.Int("days", 182, "interval in days (used if --after is not specified)")
+	verboseFlag = flag.Bool("v", false, "verbose mode - lists all the changes")
+)
+
+func main() {
+	flag.Parse()
+	if err := run(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func queryChanges(client *gerrit.Client, queryParts ...string) ([]gerrit.ChangeInfo, string, error) {
+	query := strings.Join(queryParts, "+")
+	out := []gerrit.ChangeInfo{}
+	for {
+		changes, _, err := client.Changes.QueryChanges(&gerrit.QueryChangeOptions{
+			QueryOptions: gerrit.QueryOptions{Query: []string{query}},
+			Skip:         len(out),
+		})
+		if err != nil {
+			return nil, "", err
+		}
+
+		out = append(out, *changes...)
+		if len(*changes) == 0 || !(*changes)[len(*changes)-1].MoreChanges {
+			break
+		}
+	}
+	return out, query, nil
+}
+
+func run() error {
+	var after, before time.Time
+	var err error
+	user := *userFlag
+	if user == "" {
+		return fmt.Errorf("Missing required 'user' flag")
+	}
+	if *beforeFlag != "" {
+		before, err = time.Parse(yyyymmdd, *beforeFlag)
+		if err != nil {
+			return fmt.Errorf("Couldn't parse before date: %w", err)
+		}
+	} else {
+		before = time.Now()
+	}
+	if *afterFlag != "" {
+		after, err = time.Parse(yyyymmdd, *afterFlag)
+		if err != nil {
+			return fmt.Errorf("Couldn't parse after date: %w", err)
+		}
+	} else {
+		after = before.Add(-time.Hour * time.Duration(24**daysFlag))
+	}
+
+	client, err := gerrit.NewClient(gerritURL, nil)
+	if err != nil {
+		return fmt.Errorf("Couldn't create gerrit client: %w", err)
+	}
+
+	if *gerritUser == "" {
+		cookiesFile := os.Getenv("HOME") + "/.gitcookies"
+		if cookies, err := ioutil.ReadFile(cookiesFile); err == nil {
+			re := regexp.MustCompile(`dawn-review.googlesource.com\s+(?:FALSE|TRUE)[\s/]+(?:FALSE|TRUE)\s+[0-9]+\s+.\s+(.*)=(.*)`)
+			match := re.FindStringSubmatch(string(cookies))
+			if len(match) == 3 {
+				*gerritUser, *gerritPass = match[1], match[2]
+			}
+		}
+	}
+
+	if *gerritUser != "" {
+		client.Authentication.SetBasicAuth(*gerritUser, *gerritPass)
+	}
+
+	submitted, submittedQuery, err := queryChanges(client,
+		"status:merged",
+		"owner:"+user,
+		"after:"+date(after),
+		"before:"+date(before),
+		"repo:"+*repoFlag)
+	if err != nil {
+		if *gerritUser == "" {
+			return fmt.Errorf(`Query failed, possibly because of authentication.
+See https://dawn-review.googlesource.com/new-password for obtaining a username
+and password which can be provided with --gerrit-user and --gerrit-pass.
+%w`, err)
+		}
+		return fmt.Errorf("Query failed: %w", err)
+	}
+
+	reviewed, reviewQuery, err := queryChanges(client,
+		"commentby:"+user,
+		"-owner:"+user,
+		"after:"+date(after),
+		"before:"+date(before),
+		"repo:"+*repoFlag)
+	if err != nil {
+		return fmt.Errorf("Query failed: %w", err)
+	}
+
+	ignorelist := []*regexp.Regexp{
+		regexp.MustCompile("Revert .*"),
+	}
+	ignore := func(s string) bool {
+		for _, re := range ignorelist {
+			if re.MatchString(s) {
+				return true
+			}
+		}
+		return false
+	}
+
+	insertions, deletions := 0, 0
+	for _, change := range submitted {
+		if ignore(change.Subject) {
+			continue
+		}
+		insertions += change.Insertions
+		deletions += change.Deletions
+	}
+
+	fmt.Printf("Between %v and %v, %v:\n", date(after), date(before), user)
+	fmt.Printf("  Submitted %v changes (LOC: %v+, %v-) \n", len(submitted), insertions, deletions)
+	fmt.Printf("  Reviewed %v changes\n", len(reviewed))
+	fmt.Printf("\n")
+
+	if *verboseFlag {
+		fmt.Printf("Submitted changes:\n")
+		for i, change := range submitted {
+			fmt.Printf("%3.1v: %6.v %v (LOC: %v+, %v-)\n", i, change.Number, change.Subject, change.Insertions, change.Deletions)
+		}
+		fmt.Printf("\n")
+		fmt.Printf("Reviewed changes:\n")
+		for i, change := range reviewed {
+			fmt.Printf("%3.1v: %6.v %v (LOC: %v+, %v-)\n", i, change.Number, change.Subject, change.Insertions, change.Deletions)
+		}
+	}
+
+	fmt.Printf("\n")
+	fmt.Printf("Submitted query: %vq/%v\n", gerritURL, url.QueryEscape(submittedQuery))
+	fmt.Printf("Review query: %vq/%v\n", gerritURL, url.QueryEscape(reviewQuery))
+
+	return nil
+}
+
+func today() time.Time {
+	return time.Now()
+}
+
+func date(t time.Time) string {
+	return t.Format(yyyymmdd)
+}