cmd/greplogs: associate known issues by regex

Add a flag --known issue that associates issues with log entries based
on regexp matches. It's used like this:

--known-issue='#53456=TestDebugLines'

Which results in the check box for that log being pre-checked, and the
text '#53456' being added, which turns into a pretty link on GitHub.

It might be nice to group issues as well, but I didn't want to mess with
the chronological ordering.

For golang/go#52653.

Change-Id: If4615cd798ba72c1c1ee3cb43f1d1ad6d4319528
Reviewed-on: https://go-review.googlesource.com/c/build/+/425075
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Heschi Kreinick <heschi@google.com>
Auto-Submit: Heschi Kreinick <heschi@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>

cmd/greplogs/flags.go

@@ -4,7 +4,12 @@
 
 package main
 
-import "regexp"
+import (
+	"fmt"
+	"regexp"
+	"sort"
+	"strings"
+)
 
 type regexpList []*regexp.Regexp
 
@@ -58,3 +63,45 @@ func (x *regexpList) Matches(data []byte) [][]int {
 	}
 	return matches
 }
+
+type regexpMap map[string]*regexp.Regexp
+
+func (x *regexpMap) Set(s string) error {
+	if *x == nil {
+		*x = regexpMap{}
+	}
+	k, v, ok := strings.Cut(s, "=")
+	if !ok {
+		return fmt.Errorf("missing key, expected key=value in %q", s)
+	}
+	re, err := regexp.Compile("(?m)" + v)
+	if err != nil {
+		// Get an error without our modifications.
+		_, err2 := regexp.Compile(v)
+		if err2 != nil {
+			err = err2
+		}
+		return err
+	}
+	(*x)[k] = re
+	return nil
+}
+
+func (x *regexpMap) String() string {
+	var result []string
+	for k, v := range *x {
+		result = append(result, fmt.Sprintf("%v=%v", k, v))
+	}
+	return strings.Join(result, ",")
+}
+
+func (x *regexpMap) Matches(data []byte) []string {
+	var matches []string
+	for k, r := range *x {
+		if r.Match(data) {
+			matches = append(matches, k)
+		}
+	}
+	sort.Strings(matches)
+	return matches
+}

cmd/greplogs/main.go

@@ -46,6 +46,7 @@ var (
 	fileRegexps regexpList
 	failRegexps regexpList
 	omit        regexpList
+	knownIssues regexpMap
 
 	flagDashboard = flag.Bool("dashboard", true, "search dashboard logs from fetchlogs")
 	flagMD        = flag.Bool("md", true, "output in Markdown")
@@ -69,6 +70,7 @@ var brokenBuilders []string
 func main() {
 	// XXX What I want right now is just to point it at a bunch of
 	// logs and have it extract the failures.
+	flag.Var(&knownIssues, "known-issue", "add an issue=regexp mapping; if a log matches regexp it will be categorized under issue. One mapping per flag.")
 	flag.Var(&fileRegexps, "e", "show files matching `regexp`; if provided multiple times, files must match all regexps")
 	flag.Var(&failRegexps, "E", "show only errors matching `regexp`; if provided multiple times, an error must match all regexps")
 	flag.Var(&omit, "omit", "omit results for builder names and/or revisions matching `regexp`; if provided multiple times, logs matching any regexp are omitted")
@@ -244,10 +246,17 @@ func process(path, nicePath string) (found bool, err error) {
 	}
 
 	printPath := nicePath
+	kiMatches := 0
 	if *flagMD && logURL != "" {
 		prefix := ""
 		if *flagTriage {
-			prefix = "- [ ] "
+			matches := knownIssues.Matches(data)
+			if len(matches) == 0 {
+				prefix = "- [ ] "
+			} else {
+				kiMatches++
+				prefix = fmt.Sprintf("- [x] (%v) ", strings.Join(matches, ", "))
+			}
 		}
 		printPath = fmt.Sprintf("%s[%s](%s)", prefix, nicePath, logURL)
 	}