From 0b0766c70c95e0da12db5df6e1e3085ca610a351 Mon Sep 17 00:00:00 2001
From: Robert Cunius Jr <recunius@espoc.com>
Date: Tue, 3 May 2022 17:37:43 -0400
Subject: [PATCH] add more flexible snapshot match by regular expression

---
 backup/backup.go      | 25 ++++++++++++++++++++++++-
 backup/backup_test.go | 13 +++++++++++++
 cmd/send.go           |  6 ++++++
 files/jobinfo.go      |  1 +
 4 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/backup/backup.go b/backup/backup.go
index 29245d8..036cb64 100644
--- a/backup/backup.go
+++ b/backup/backup.go
@@ -31,6 +31,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strings"
 	"sync"
@@ -54,6 +55,22 @@ var (
 	manifestmutex sync.Mutex
 )
 
+type snapshotFilter struct {
+	prefix      string
+	regexpMatch *regexp.Regexp
+}
+
+func newSnapshotFilter(prefix string, match string) *snapshotFilter {
+	filter := &snapshotFilter{
+		prefix: prefix,
+	}
+	if match != "" {
+		filter.regexpMatch = regexp.MustCompile(match)
+	}
+	log.AppLogger.Debugf("Filtering snapshots with prefix = %s, regex matcher = %v", filter.prefix, filter.regexpMatch)
+	return filter
+}
+
 // ProcessSmartOptions will compute the snapshots to use
 // nolint:funlen,gocyclo // Difficult to break this up
 func ProcessSmartOptions(ctx context.Context, jobInfo *files.JobInfo) error {
@@ -61,11 +78,12 @@ func ProcessSmartOptions(ctx context.Context, jobInfo *files.JobInfo) error {
 	if err != nil {
 		return err
 	}
+	filter := newSnapshotFilter(jobInfo.SnapshotPrefix, jobInfo.SnapshotRegexp)
 	// Base Snapshots cannot be a bookmark
 	for i := range snapshots {
 		log.AppLogger.Debugf("Considering snapshot %s", snapshots[i].Name)
 		if !snapshots[i].Bookmark {
-			if jobInfo.SnapshotPrefix == "" || strings.HasPrefix(snapshots[i].Name, jobInfo.SnapshotPrefix) {
+			if includeSnapshot(&snapshots[i], filter) {
 				log.AppLogger.Debugf("Matched snapshot: %s", snapshots[i].Name)
 				jobInfo.BaseSnapshot = snapshots[i]
 				break
@@ -163,6 +181,11 @@ func ProcessSmartOptions(ctx context.Context, jobInfo *files.JobInfo) error {
 	return nil
 }
 
+func includeSnapshot(snapshot *files.SnapshotInfo, filter *snapshotFilter) bool {
+	return (filter.prefix == "" || strings.HasPrefix(snapshot.Name, filter.prefix)) &&
+		(filter.regexpMatch == nil || filter.regexpMatch.MatchString(snapshot.Name))
+}
+
 // Will list all backups found in the target destination
 func getBackupsForTarget(ctx context.Context, volume, target string, jobInfo *files.JobInfo) ([]*files.JobInfo, error) {
 	// Prepare the backend client
diff --git a/backup/backup_test.go b/backup/backup_test.go
index 3ddc4c3..9cc738a 100644
--- a/backup/backup_test.go
+++ b/backup/backup_test.go
@@ -65,6 +65,19 @@ type errTestFunc func(error) bool
 
 func nilErrTest(e error) bool { return e == nil }
 
+func TestIncludeSnapshot(t *testing.T) {
+	filter := newSnapshotFilter("", "^weekly.*")
+
+	snapInfo := &files.SnapshotInfo{Name: "hourly123"}
+	if includeSnapshot(snapInfo, filter) {
+		t.Errorf("%s incorrectly included", snapInfo.Name)
+	}
+	snapInfo.Name = "weekly456"
+	if !includeSnapshot(snapInfo, filter) {
+		t.Errorf("%s incorrectly excluded", snapInfo.Name)
+	}
+}
+
 func TestRetryUploadChainer(t *testing.T) {
 	_, goodVol, badVol, err := prepareTestVols()
 	if err != nil {
diff --git a/cmd/send.go b/cmd/send.go
index bba5cdd..95b75bf 100644
--- a/cmd/send.go
+++ b/cmd/send.go
@@ -117,6 +117,12 @@ func init() {
 		"",
 		"Only consider snapshots starting with the given snapshot prefix",
 	)
+	sendCmd.Flags().StringVar(
+		&jobInfo.SnapshotRegexp,
+		"snapshotRegexp",
+		"",
+		"Only consider snapshots matching given regex",
+	)
 	sendCmd.Flags().DurationVar(
 		&jobInfo.FullIfOlderThan,
 		"fullIfOlderThan",
diff --git a/files/jobinfo.go b/files/jobinfo.go
index f424a0c..ab0e204 100644
--- a/files/jobinfo.go
+++ b/files/jobinfo.go
@@ -45,6 +45,7 @@ type JobInfo struct {
 	BaseSnapshot            SnapshotInfo
 	IncrementalSnapshot     SnapshotInfo
 	SnapshotPrefix          string
+	SnapshotRegexp          string
 	Compressor              string
 	CompressionLevel        int
 	Separator               string