Add bisect_roll tool

1. Loads the list of commits which have not yet rolled.
2. Loads the recent roll attempts.
3. Suggests a commit to try.
4. Uploads a roll CL at the commit specified by the user.

Bug: skia:
Change-Id: I68a7f6dbbca638cc9f17bad4eed71e889fe43b6e
Reviewed-on: https://skia-review.googlesource.com/93580
Commit-Queue: Eric Boren <borenet@google.com>
Reviewed-by: Ravi Mistry <rmistry@google.com>

1 files changed, 209 insertions, 0 deletions

diff --git a/tools/bisect_roll.go b/tools/bisect_roll.go
new file mode 100644
index 0000000000..3bc4262c91
--- /dev/null
+++ b/tools/bisect_roll.go
@@ -0,0 +1,209 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package main
+
+/*
+   Tool for bisecting failed rolls.
+*/
+
+import (
+	"bufio"
+	"context"
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"os/user"
+	"path"
+	"strings"
+	"time"
+
+	"go.skia.org/infra/autoroll/go/repo_manager"
+	"go.skia.org/infra/go/autoroll"
+	"go.skia.org/infra/go/common"
+	"go.skia.org/infra/go/gerrit"
+	"go.skia.org/infra/go/util"
+)
+
+var (
+	// Flags.
+	autoRollerAccount = flag.String("autoroller_account", "skia-deps-roller@chromium.org", "Email address of the autoroller.")
+	childPath         = flag.String("childPath", "src/third_party/skia", "Path within parent repo of the project to roll.")
+	gerritUrl         = flag.String("gerrit", "https://chromium-review.googlesource.com", "URL of the Gerrit server.")
+	parentRepoUrl     = flag.String("parent_repo_url", common.REPO_CHROMIUM, "URL of the parent repo (the child repo rolls into this repo).")
+	workdir           = flag.String("workdir", path.Join(os.TempDir(), "autoroll_bisect"), "Working directory.")
+)
+
+func log(tmpl string, a ...interface{}) {
+	fmt.Println(fmt.Sprintf(tmpl, a...))
+}
+
+func bail(a ...interface{}) {
+	fmt.Fprintln(os.Stderr, a...)
+	os.Exit(1)
+}
+
+func main() {
+	// Setup.
+	common.Init()
+	ctx := context.Background()
+
+	log("Updating repos and finding roll attempts; this can take a few minutes...")
+
+	// Create the working directory if necessary.
+	if err := os.MkdirAll(*workdir, os.ModePerm); err != nil {
+		bail(err)
+	}
+
+	// Create the RepoManager.
+	gclient, err := exec.LookPath("gclient")
+	if err != nil {
+		bail(err)
+	}
+	depotTools := path.Dir(gclient)
+	user, err := user.Current()
+	if err != nil {
+		bail(err)
+	}
+	gitcookiesPath := path.Join(user.HomeDir, ".gitcookies")
+	g, err := gerrit.NewGerrit(*gerritUrl, gitcookiesPath, nil)
+	if err != nil {
+		bail("Failed to create Gerrit client:", err)
+	}
+	g.TurnOnAuthenticatedGets()
+	childBranch := "master"
+	strat, err := repo_manager.GetNextRollStrategy(repo_manager.ROLL_STRATEGY_BATCH, childBranch, "")
+	if err != nil {
+		bail(err)
+	}
+	rm, err := repo_manager.NewDEPSRepoManager(ctx, *workdir, *parentRepoUrl, "master", *childPath, childBranch, depotTools, g, strat, nil, true, nil, "(local run)")
+	if err != nil {
+		bail(err)
+	}
+
+	// Determine the set of not-yet-rolled commits.
+	lastRoll := rm.LastRollRev()
+	nextRoll := rm.NextRollRev()
+	commits, err := rm.ChildRevList(ctx, fmt.Sprintf("%s..%s", lastRoll, nextRoll))
+	if err != nil {
+		bail(err)
+	}
+	if len(commits) == 0 {
+		log("Repo is up-to-date.")
+		os.Exit(0)
+	} else if len(commits) == 1 {
+		log("Recommend reverting commit %s", commits[0])
+		os.Exit(0)
+	}
+
+	// Next, find any failed roll CLs.
+	// TODO(borenet): Use the timestamp of the last-rolled commit.
+	lastRollTime := time.Now().Add(-24 * time.Hour)
+	modAfter := gerrit.SearchModifiedAfter(lastRollTime)
+	cls, err := g.Search(500, modAfter, gerrit.SearchOwner(*autoRollerAccount))
+	if err != nil {
+		bail(err)
+	}
+	cls2, err := g.Search(500, modAfter, gerrit.SearchOwner("self"))
+	if err != nil {
+		bail(err)
+	}
+	cls = append(cls, cls2...)
+
+	// Filter out CLs which don't look like rolls, de-duplicate CLs which
+	// roll to the same commit, taking the most recent.
+	rollCls := make(map[string]*autoroll.AutoRollIssue, len(cls))
+	fullHashFn := func(hash string) (string, error) {
+		return rm.FullChildHash(ctx, hash)
+	}
+	for _, cl := range cls {
+		issue, err := autoroll.FromGerritChangeInfo(cl, fullHashFn, false)
+		if err == nil {
+			if old, ok := rollCls[issue.RollingTo]; !ok || ok && issue.Modified.After(old.Modified) {
+				rollCls[issue.RollingTo] = issue
+			}
+		}
+	}
+
+	// Report the summary of the not-rolled commits and their associated
+	// roll results to the user.
+	log("%d commits have not yet rolled:", len(commits))
+	earliestFail := -1
+	latestFail := -1
+	latestSuccess := -1 // eg. dry runs.
+	for idx, commit := range commits {
+		if cl, ok := rollCls[commit]; ok {
+			log("%s roll %s", commit[:12], cl.Result)
+			if util.In(cl.Result, autoroll.FAILURE_RESULTS) {
+				earliestFail = idx
+				if latestFail == -1 {
+					latestFail = idx
+				}
+			} else if util.In(cl.Result, autoroll.SUCCESS_RESULTS) && latestSuccess == -1 {
+				latestSuccess = idx
+			}
+		} else {
+			log(commit[:12])
+		}
+	}
+
+	// Suggest a commit to try rolling. The user may choose a different one.
+	suggestedCommit := ""
+	if latestSuccess != -1 {
+		suggestedCommit = commits[latestSuccess]
+		log("Recommend landing successful roll %s/%d", *gerritUrl, rollCls[suggestedCommit].Issue)
+	} else if latestFail != 0 {
+		suggestedCommit = commits[0]
+		if issue, ok := rollCls[suggestedCommit]; ok && issue.Result == autoroll.ROLL_RESULT_IN_PROGRESS {
+			log("Recommend waiting for the current in-progress roll to finish: %s/%d", *gerritUrl, issue.Issue)
+			suggestedCommit = ""
+		} else {
+			log("Recommend trying a roll at %s which has not yet been tried.", suggestedCommit)
+		}
+	} else if earliestFail == 0 {
+		log("Recommend reverting commit %s", commits[earliestFail])
+	} else {
+		// Bisect the commits which have not yet failed.
+		remaining := commits[earliestFail+1:]
+		idx := len(remaining) / 2
+		suggestedCommit = remaining[idx]
+		log("Recommend trying a roll at %s", suggestedCommit)
+	}
+
+	// Ask the user what commit to roll.
+	msg := "Type a commit hash to roll"
+	if suggestedCommit != "" {
+		msg += fmt.Sprintf(" (press enter to roll at suggested commit %s)", suggestedCommit[:12])
+	}
+	log("%s:", msg)
+	reader := bufio.NewReader(os.Stdin)
+	text, err := reader.ReadString('\n')
+	if err != nil {
+		bail(err)
+	}
+	text = strings.TrimSpace(text)
+	if text == "" && suggestedCommit != "" {
+		text = suggestedCommit
+	}
+	if text == "" {
+		bail("You must enter a commit hash.")
+	}
+	log("Attempting a roll at %q", text)
+	rollTo, err := rm.FullChildHash(ctx, text)
+	if err != nil {
+		bail(text, "is not a valid commit hash:", text, err)
+	}
+
+	// Upload a roll.
+	email, err := g.GetUserEmail()
+	if err != nil {
+		bail(err)
+	}
+	issue, err := rm.CreateNewRoll(ctx, lastRoll, rollTo, []string{email}, "", false)
+	if err != nil {
+		bail(err)
+	}
+	log("Uploaded %s/%d", *gerritUrl, issue)
+}