MM-9728: Online migration for advanced permissions phase 2 (#8744)

* MM-9728: Online migration for advanced permissions phase 2

* Add unit tests for new store functions.

* Move migration specific code to own file.

* Add migration state function test.

* Style fixes.

* Add i18n strings.

* Fix mocks.

* Add TestMain to migrations package tests.

* Fix typo.

* Fix review comments.

* Fix up the "Check if migration is done" check to actually work.

1 files changed, 106 insertions, 0 deletions

diff --git a/migrations/advanced_permissions_phase_2.go b/migrations/advanced_permissions_phase_2.go
new file mode 100644
index 000000000..55b1876c4
--- /dev/null
+++ b/migrations/advanced_permissions_phase_2.go
@@ -0,0 +1,106 @@
+// Copyright (c) 2018-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package migrations
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/mattermost/mattermost-server/model"
+)
+
+type AdvancedPermissionsPhase2Progress struct {
+	CurrentTable  string `json:"current_table"`
+	LastTeamId    string `json:"last_team_id"`
+	LastChannelId string `json:"last_channel_id"`
+	LastUserId    string `json:"last_user"`
+}
+
+func (p *AdvancedPermissionsPhase2Progress) ToJson() string {
+	b, _ := json.Marshal(p)
+	return string(b)
+}
+
+func AdvancedPermissionsPhase2ProgressFromJson(data io.Reader) *AdvancedPermissionsPhase2Progress {
+	var o *AdvancedPermissionsPhase2Progress
+	json.NewDecoder(data).Decode(&o)
+	return o
+}
+
+func (p *AdvancedPermissionsPhase2Progress) IsValid() bool {
+	if len(p.LastChannelId) != 26 {
+		return false
+	}
+
+	if len(p.LastTeamId) != 26 {
+		return false
+	}
+
+	if len(p.LastUserId) != 26 {
+		return false
+	}
+
+	switch p.CurrentTable {
+	case "TeamMembers":
+	case "ChannelMembers":
+	default:
+		return false
+	}
+
+	return true
+}
+
+func (worker *Worker) runAdvancedPermissionsPhase2Migration(lastDone string) (bool, string, *model.AppError) {
+	var progress *AdvancedPermissionsPhase2Progress
+	if len(lastDone) == 0 {
+		// Haven't started the migration yet.
+		progress = new(AdvancedPermissionsPhase2Progress)
+		progress.CurrentTable = "TeamMembers"
+		progress.LastChannelId = strings.Repeat("0", 26)
+		progress.LastTeamId = strings.Repeat("0", 26)
+		progress.LastUserId = strings.Repeat("0", 26)
+	} else {
+		progress = AdvancedPermissionsPhase2ProgressFromJson(strings.NewReader(lastDone))
+		if !progress.IsValid() {
+			return false, "", model.NewAppError("MigrationsWorker.runAdvancedPermissionsPhase2Migration", "migrations.worker.run_advanced_permissions_phase_2_migration.invalid_progress", map[string]interface{}{"progress": progress.ToJson()}, "", http.StatusInternalServerError)
+		}
+	}
+
+	if progress.CurrentTable == "TeamMembers" {
+		// Run a TeamMembers migration batch.
+		if result := <-worker.app.Srv.Store.Team().MigrateTeamMembers(progress.LastTeamId, progress.LastUserId); result.Err != nil {
+			return false, progress.ToJson(), result.Err
+		} else {
+			if result.Data == nil {
+				// We haven't progressed. That means that we've reached the end of this stage of the migration, and should now advance to the next stage.
+				progress.LastUserId = strings.Repeat("0", 26)
+				progress.CurrentTable = "ChannelMembers"
+				return false, progress.ToJson(), nil
+			}
+
+			data := result.Data.(map[string]string)
+			progress.LastTeamId = data["TeamId"]
+			progress.LastUserId = data["UserId"]
+		}
+	} else if progress.CurrentTable == "ChannelMembers" {
+		// Run a ChannelMembers migration batch.
+		if result := <-worker.app.Srv.Store.Channel().MigrateChannelMembers(progress.LastChannelId, progress.LastUserId); result.Err != nil {
+			return false, progress.ToJson(), result.Err
+		} else {
+			if result.Data == nil {
+				// We haven't progressed. That means we've reached the end of this final stage of the migration.
+
+				return true, progress.ToJson(), nil
+			}
+
+			data := result.Data.(map[string]string)
+			progress.LastChannelId = data["ChannelId"]
+			progress.LastUserId = data["UserId"]
+		}
+	}
+
+	return false, progress.ToJson(), nil
+}