From bf8606a9318adf6128157a59d42ddd71e14067a5 Mon Sep 17 00:00:00 2001
From: Vitaly Baranov <vitbar@yandex-team.ru>
Date: Sat, 6 Nov 2021 13:56:07 +0300
Subject: [PATCH] Add UUID and timestamp to backup metadata.

---
 base/base/LocalDateTime.h         |  5 +++++
 src/Backups/BackupInDirectory.cpp | 23 +++++++++++++++++++++--
 src/Backups/BackupInDirectory.h   |  5 +++++
 src/Backups/IBackup.h             |  6 ++++++
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/base/base/LocalDateTime.h b/base/base/LocalDateTime.h
index 0edc12374bb..282a56ac640 100644
--- a/base/base/LocalDateTime.h
+++ b/base/base/LocalDateTime.h
@@ -108,6 +108,11 @@ public:
     LocalDate toDate() const { return LocalDate(m_year, m_month, m_day); }
     LocalDateTime toStartOfDate() const { return LocalDateTime(m_year, m_month, m_day, 0, 0, 0); }
 
+    time_t to_time_t(const DateLUTImpl & time_zone = DateLUT::instance()) const
+    {
+        return time_zone.makeDateTime(m_year, m_month, m_day, m_hour, m_minute, m_second);
+    }
+
     std::string toString() const
     {
         std::string s{"0000-00-00 00:00:00"};
diff --git a/src/Backups/BackupInDirectory.cpp b/src/Backups/BackupInDirectory.cpp
index 7e61cbdba2e..ecd92fe3724 100644
--- a/src/Backups/BackupInDirectory.cpp
+++ b/src/Backups/BackupInDirectory.cpp
@@ -86,6 +86,9 @@ void BackupInDirectory::open()
             disk->createDirectories(path);
             directory_was_created = true;
         }
+
+        timestamp = std::time(nullptr);
+        uuid = UUIDHelpers::generateV4();
     }
 
     if (open_mode == OpenMode::READ)
@@ -102,6 +105,12 @@ void BackupInDirectory::open()
         params.open_mode = OpenMode::READ;
         params.context = context;
         base_backup = BackupFactory::instance().createBackup(params);
+
+        if (open_mode == OpenMode::WRITE)
+            base_backup_uuid = base_backup->getUUID();
+        else if (base_backup_uuid != base_backup->getUUID())
+            throw Exception(ErrorCodes::WRONG_BASE_BACKUP, "Backup {}: The base backup {} has different UUID ({} != {})",
+                            getName(), base_backup->getName(), toString(base_backup->getUUID()), (base_backup_uuid ? toString(*base_backup_uuid) : ""));
     }
 }
 
@@ -122,9 +131,13 @@ void BackupInDirectory::writeMetadata()
 {
     Poco::AutoPtr<Poco::Util::XMLConfiguration> config{new Poco::Util::XMLConfiguration()};
     config->setUInt("version", BACKUP_VERSION);
+    config->setString("timestamp", toString(LocalDateTime{timestamp}));
+    config->setString("uuid", toString(uuid));
 
     if (base_backup_info)
         config->setString("base_backup", base_backup_info->toString());
+    if (base_backup_uuid)
+        config->setString("base_backup_uuid", toString(*base_backup_uuid));
 
     size_t index = 0;
     for (const auto & [name, info] : infos)
@@ -160,12 +173,18 @@ void BackupInDirectory::readMetadata()
     Poco::AutoPtr<Poco::Util::XMLConfiguration> config{new Poco::Util::XMLConfiguration()};
     config->load(stream);
 
-    UInt64 version = config->getUInt("version", 1);
+    UInt64 version = config->getUInt("version");
     if (version != BACKUP_VERSION)
         throw Exception(ErrorCodes::BACKUP_VERSION_NOT_SUPPORTED, "Backup {}: Version {} is not supported", getName(), version);
 
+    timestamp = parse<LocalDateTime>(config->getString("timestamp")).to_time_t();
+    uuid = parse<UUID>(config->getString("uuid"));
+
     if (config->has("base_backup") && !base_backup_info)
-        base_backup_info.emplace(BackupInfo::fromString(config->getString("base_backup")));
+        base_backup_info = BackupInfo::fromString(config->getString("base_backup"));
+
+    if (config->has("base_backup_uuid") && !base_backup_uuid)
+        base_backup_uuid = parse<UUID>(config->getString("base_backup_uuid"));
 
     infos.clear();
     Poco::Util::AbstractConfiguration::Keys keys;
diff --git a/src/Backups/BackupInDirectory.h b/src/Backups/BackupInDirectory.h
index 14cb1f82f39..16a48f3690c 100644
--- a/src/Backups/BackupInDirectory.h
+++ b/src/Backups/BackupInDirectory.h
@@ -33,6 +33,8 @@ public:
 
     const String & getName() const override { return backup_name; }
     OpenMode getOpenMode() const override { return open_mode; }
+    time_t getTimestamp() const override { return timestamp; }
+    UUID getUUID() const override { return uuid; }
     Strings list(const String & prefix, const String & terminator) const override;
     bool exists(const String & name) const override;
     size_t getSize(const String & name) const override;
@@ -59,11 +61,14 @@ private:
 
     const String backup_name;
     const OpenMode open_mode;
+    UUID uuid;
+    time_t timestamp;
     DiskPtr disk;
     String path;
     ContextPtr context;
     std::optional<BackupInfo> base_backup_info;
     std::shared_ptr<const IBackup> base_backup;
+    std::optional<UUID> base_backup_uuid;
     std::map<String, EntryInfo> infos;
     bool directory_was_created = false;
     bool finalized = false;
diff --git a/src/Backups/IBackup.h b/src/Backups/IBackup.h
index 0130665a343..8a6020a604e 100644
--- a/src/Backups/IBackup.h
+++ b/src/Backups/IBackup.h
@@ -31,6 +31,12 @@ public:
     /// A backup can be open either in READ or WRITE mode.
     virtual OpenMode getOpenMode() const = 0;
 
+    /// Returns the time point when this backup was created.
+    virtual time_t getTimestamp() const = 0;
+
+    /// Returns UUID of the backup.
+    virtual UUID getUUID() const = 0;
+
     /// Returns names of entries stored in the backup.
     /// If `prefix` isn't empty the function will return only the names starting with
     /// the prefix (but without the prefix itself).