br: migrate restore checkpoint data to the downstream cluster temporary database

br/pkg/checkpoint/BUILD.bazel

@@ -5,23 +5,30 @@ go_library(
     srcs = [
         "backup.go",
         "checkpoint.go",
+        "external_storage.go",
         "log_restore.go",
         "restore.go",
+        "storage.go",
         "ticker.go",
     ],
     importpath = "github.com/pingcap/tidb/br/pkg/checkpoint",
     visibility = ["//visibility:public"],
     deps = [
+        "//br/pkg/glue",
         "//br/pkg/logutil",
         "//br/pkg/metautil",
         "//br/pkg/pdutil",
         "//br/pkg/rtree",
         "//br/pkg/storage",
         "//br/pkg/summary",
         "//br/pkg/utils",
+        "//pkg/domain",
+        "//pkg/kv",
         "//pkg/meta/model",
         "//pkg/parser/model",
         "//pkg/util",
+        "//pkg/util/sqlexec",
+        "@com_github_google_uuid//:uuid",
         "@com_github_pingcap_errors//:errors",
         "@com_github_pingcap_failpoint//:failpoint",
         "@com_github_pingcap_kvproto//pkg/brpb",
@@ -38,11 +45,13 @@ go_test(
     srcs = ["checkpoint_test.go"],
     flaky = True,
     race = "on",
-    shard_count = 5,
+    shard_count = 6,
     deps = [
         ":checkpoint",
+        "//br/pkg/gluetidb",
         "//br/pkg/pdutil",
         "//br/pkg/storage",
+        "//br/pkg/utiltest",
         "//pkg/meta/model",
         "//pkg/parser/model",
         "@com_github_pingcap_kvproto//pkg/brpb",

br/pkg/checkpoint/backup.go

@@ -57,13 +57,13 @@ func StartCheckpointBackupRunnerForTest(
 	tick time.Duration,
 	timer GlobalTimer,
 ) (*CheckpointRunner[BackupKeyType, BackupValueType], error) {
-	runner := newCheckpointRunner[BackupKeyType, BackupValueType](
-		ctx, storage, cipher, timer, flushPositionForBackup(), valueMarshalerForBackup)
-
-	err := runner.initialLock(ctx)
+	checkpointStorage, err := newExternalCheckpointStorage(ctx, storage, timer)
 	if err != nil {
-		return nil, errors.Annotate(err, "Failed to initialize checkpoint lock.")
+		return nil, errors.Trace(err)
 	}
+	runner := newCheckpointRunner[BackupKeyType, BackupValueType](
+		checkpointStorage, cipher, valueMarshalerForBackup)
+
 	runner.startCheckpointMainLoop(ctx, tick, tick, tick)
 	return runner, nil
 }
@@ -74,13 +74,13 @@ func StartCheckpointRunnerForBackup(
 	cipher *backuppb.CipherInfo,
 	timer GlobalTimer,
 ) (*CheckpointRunner[BackupKeyType, BackupValueType], error) {
-	runner := newCheckpointRunner[BackupKeyType, BackupValueType](
-		ctx, storage, cipher, timer, flushPositionForBackup(), valueMarshalerForBackup)
-
-	err := runner.initialLock(ctx)
+	checkpointStorage, err := newExternalCheckpointStorage(ctx, storage, timer)
 	if err != nil {
 		return nil, errors.Trace(err)
 	}
+	runner := newCheckpointRunner[BackupKeyType, BackupValueType](
+		checkpointStorage, cipher, valueMarshalerForBackup)
+
 	runner.startCheckpointMainLoop(
 		ctx,
 		defaultTickDurationForFlush,