Add --skip-db option to dump command (go-gitea#30613)

Attempts to resolve go-gitea#28720.

---

Note that I am not a Gitea administrator so I don't normally use the
gitea CLI. Just saw this issue and wanted an opportunity to understand
how this subcommand works and see if I can add this feature :^)

I tested both with `--skip-db` and without and it appears to not add any
database-specific files to the generated archive i.e. I don't see a
`gitea-db.sql` or `gitea.db` file:
```console
$ TAGS="bindata sqlite sqlite_unlock_notify" make backend
Running go generate...
bindata for migration already up-to-date
bindata for options already up-to-date
bindata for public already up-to-date
bindata for templates already up-to-date
$ ./gitea dump --skip-db
2024/04/20 01:16:11 ...s/setting/session.go:77:loadSessionFrom() [I] Session Service Enabled
2024/04/20 01:16:11 ...s/storage/storage.go:176:initAttachments() [I] Initialising Attachment storage with type: local
2024/04/20 01:16:11 ...les/storage/local.go:33:NewLocalStorage() [I] Creating new Local Storage at /workspaces/gitea/data/attachments
2024/04/20 01:16:11 ...s/storage/storage.go:166:initAvatars() [I] Initialising Avatar storage with type: local
2024/04/20 01:16:11 ...les/storage/local.go:33:NewLocalStorage() [I] Creating new Local Storage at /workspaces/gitea/data/avatars
2024/04/20 01:16:11 ...s/storage/storage.go:192:initRepoAvatars() [I] Initialising Repository Avatar storage with type: local
2024/04/20 01:16:11 ...les/storage/local.go:33:NewLocalStorage() [I] Creating new Local Storage at /workspaces/gitea/data/repo-avatars
2024/04/20 01:16:11 ...s/storage/storage.go:186:initLFS() [I] Initialising LFS storage with type: local
2024/04/20 01:16:11 ...les/storage/local.go:33:NewLocalStorage() [I] Creating new Local Storage at /workspaces/gitea/data/lfs
2024/04/20 01:16:11 ...s/storage/storage.go:198:initRepoArchives() [I] Initialising Repository Archive storage with type: local
2024/04/20 01:16:11 ...les/storage/local.go:33:NewLocalStorage() [I] Creating new Local Storage at /workspaces/gitea/data/repo-archive
2024/04/20 01:16:11 ...s/storage/storage.go:208:initPackages() [I] Initialising Packages storage with type: local
2024/04/20 01:16:11 ...les/storage/local.go:33:NewLocalStorage() [I] Creating new Local Storage at /workspaces/gitea/data/packages
2024/04/20 01:16:11 ...s/storage/storage.go:219:initActions() [I] Initialising Actions storage with type: local
2024/04/20 01:16:11 ...les/storage/local.go:33:NewLocalStorage() [I] Creating new Local Storage at /workspaces/gitea/data/actions_log
2024/04/20 01:16:11 ...s/storage/storage.go:223:initActions() [I] Initialising ActionsArtifacts storage with type: local
2024/04/20 01:16:11 ...les/storage/local.go:33:NewLocalStorage() [I] Creating new Local Storage at /workspaces/gitea/data/actions_artifacts
2024/04/20 01:16:11 cmd/dump.go:172:runDump() [I] Dumping local repositories... /workspaces/gitea/data/gitea-repositories
2024/04/20 01:16:11 cmd/dump.go:195:runDump() [I] Skipping database
2024/04/20 01:16:11 cmd/dump.go:229:runDump() [I] Adding custom configuration file from /workspaces/gitea/custom/conf/app.ini
2024/04/20 01:16:11 cmd/dump.go:256:runDump() [I] Packing data directory.../workspaces/gitea/data
2024/04/20 01:16:11 cmd/dump.go:335:runDump() [I] Finish dumping in file /workspaces/gitea/gitea-dump-1713575771.zip
$ unzip /workspaces/gitea/gitea-dump-1713575771.zip -d example
Archive:  /workspaces/gitea/gitea-dump-1713575771.zip
. . .
$ ls example/
app.ini  custom  data  repos
$ ls example/data/
actions_artifacts  actions_log  avatars  home  indexers  jwt  queues  repo-archive  repo-avatars  tmp
```

Co-authored-by: Giteabot <[email protected]>

Author: kemzeb

cmd/dump.go

@@ -87,6 +87,10 @@ var CmdDump = &cli.Command{
 			Name:  "skip-index",
 			Usage: "Skip bleve index data",
 		},
+		&cli.BoolFlag{
+			Name:  "skip-db",
+			Usage: "Skip database",
+		},
 		&cli.StringFlag{
 			Name:  "type",
 			Usage: fmt.Sprintf(`Dump output format, default to "zip", supported types: %s`, strings.Join(dump.SupportedOutputTypes, ", ")),
@@ -185,35 +189,41 @@ func runDump(ctx *cli.Context) error {
 		}
 	}
 
-	tmpDir := ctx.String("tempdir")
-	if _, err := os.Stat(tmpDir); os.IsNotExist(err) {
-		fatal("Path does not exist: %s", tmpDir)
-	}
+	if ctx.Bool("skip-db") {
+		// Ensure that we don't dump the database file that may reside in setting.AppDataPath or elsewhere.
+		dumper.GlobalExcludeAbsPath(setting.Database.Path)
+		log.Info("Skipping database")
+	} else {
+		tmpDir := ctx.String("tempdir")
+		if _, err := os.Stat(tmpDir); os.IsNotExist(err) {
+			fatal("Path does not exist: %s", tmpDir)
+		}
 
-	dbDump, err := os.CreateTemp(tmpDir, "gitea-db.sql")
-	if err != nil {
-		fatal("Failed to create tmp file: %v", err)
-	}
-	defer func() {
-		_ = dbDump.Close()
-		if err := util.Remove(dbDump.Name()); err != nil {
-			log.Warn("Unable to remove temporary file: %s: Error: %v", dbDump.Name(), err)
+		dbDump, err := os.CreateTemp(tmpDir, "gitea-db.sql")
+		if err != nil {
+			fatal("Failed to create tmp file: %v", err)
 		}
-	}()
+		defer func() {
+			_ = dbDump.Close()
+			if err := util.Remove(dbDump.Name()); err != nil {
+				log.Warn("Unable to remove temporary file: %s: Error: %v", dbDump.Name(), err)
+			}
+		}()
 
-	targetDBType := ctx.String("database")
-	if len(targetDBType) > 0 && targetDBType != setting.Database.Type.String() {
-		log.Info("Dumping database %s => %s...", setting.Database.Type, targetDBType)
-	} else {
-		log.Info("Dumping database...")
-	}
+		targetDBType := ctx.String("database")
+		if len(targetDBType) > 0 && targetDBType != setting.Database.Type.String() {
+			log.Info("Dumping database %s => %s...", setting.Database.Type, targetDBType)
+		} else {
+			log.Info("Dumping database...")
+		}
 
-	if err := db.DumpDatabase(dbDump.Name(), targetDBType); err != nil {
-		fatal("Failed to dump database: %v", err)
-	}
+		if err := db.DumpDatabase(dbDump.Name(), targetDBType); err != nil {
+			fatal("Failed to dump database: %v", err)
+		}
 
-	if err = dumper.AddFile("gitea-db.sql", dbDump.Name()); err != nil {
-		fatal("Failed to include gitea-db.sql: %v", err)
+		if err = dumper.AddFile("gitea-db.sql", dbDump.Name()); err != nil {
+			fatal("Failed to include gitea-db.sql: %v", err)
+		}
 	}
 
 	log.Info("Adding custom configuration file from %s", setting.CustomConf)