Initial hot_backup

The idea being that a consistent inker manifest and set of journal files is guaranteed - with hard links to the actual manifest files.

include/leveled.hrl

@@ -1,3 +1,6 @@
+% File paths
+-define(JOURNAL_FP, "journal").
+-define(LEDGER_FP, "ledger").
 
 %% Tag to be used on standard Riak KV objects
 -define(RIAK_TAG, o_rkv).

src/leveled_bookie.erl

@@ -63,6 +63,7 @@
         book_compactjournal/2,
         book_islastcompactionpending/1,
         book_trimjournal/1,
+        book_hotbackup/1,
         book_close/1,
         book_destroy/1,
         book_isempty/2]).
@@ -76,8 +77,6 @@
 -include_lib("eunit/include/eunit.hrl").
 
 -define(CACHE_SIZE, 2500).
--define(JOURNAL_FP, "journal").
--define(LEDGER_FP, "ledger").
 -define(SNAPSHOT_TIMEOUT, 300000).
 -define(CACHE_SIZE_JITTER, 25).
 -define(JOURNAL_SIZE_JITTER, 20).
@@ -587,6 +586,19 @@ book_destroy(Pid) ->
     gen_server:call(Pid, destroy, infinity).
 
 
+-spec book_hotbackup(pid()) -> {async, fun()}.
+%% @doc Backup the Bookie
+%% Return a function that will take a backup of a snapshot of the Journal.
+%% The function will be 1-arity, and can be passed the absolute folder name
+%% to store the backup.
+%% 
+%% Backup files are hard-linked.  Does not work in head_only mode
+%%
+%% TODO: Can extend to head_only mode, and also support another parameter 
+%% which would backup persisted part of ledger (to make restart faster)
+book_hotbackup(Pid) ->
+    gen_server:call(Pid, hot_backup, infinity). 
+
 -spec book_isempty(pid(), leveled_codec:tag()) -> boolean().
 %% @doc 
 %% Confirm if the store is empty, or if it contains a Key and Value for a 
@@ -842,6 +854,19 @@ handle_call(confirm_compact, _From, State)
 handle_call(trim, _From, State) when State#state.head_only == true ->
     PSQN = leveled_penciller:pcl_persistedsqn(State#state.penciller),
     {reply, leveled_inker:ink_trim(State#state.inker, PSQN), State};
+handle_call(hot_backup, _From, State) when State#state.head_only == false ->
+    ok = leveled_inker:ink_roll(State#state.inker),
+    BackupFun = 
+        fun(InkerSnapshot) ->
+            fun(BackupPath) ->
+                ok = leveled_inker:ink_backup(InkerSnapshot, BackupPath),
+                ok = leveled_inker:ink_close(InkerSnapshot)
+            end
+        end,
+    InkerOpts = 
+        #inker_options{start_snapshot=true, source_inker=State#state.inker},
+    {ok, Snapshot} = leveled_inker:ink_snapstart(InkerOpts),
+    {reply, {async, BackupFun(Snapshot)}, State};
 handle_call(close, _From, State) ->
     leveled_inker:ink_close(State#state.inker),
     leveled_penciller:pcl_close(State#state.penciller),
@@ -1019,8 +1044,8 @@ set_options(Opts) ->
     PCLL0CacheSize = proplists:get_value(max_pencillercachesize, Opts),
     RootPath = proplists:get_value(root_path, Opts),
 
-    JournalFP = RootPath ++ "/" ++ ?JOURNAL_FP,
+    JournalFP = filename:join(RootPath, ?JOURNAL_FP),
-    LedgerFP = RootPath ++ "/" ++ ?LEDGER_FP,
+    LedgerFP = filename:join(RootPath, ?LEDGER_FP),
     ok = filelib:ensure_dir(JournalFP),
     ok = filelib:ensure_dir(LedgerFP),
 

src/leveled_cdb.erl

@@ -100,6 +100,7 @@
             cdb_destroy/1,
             cdb_deletepending/1,
             cdb_deletepending/3,
+            cdb_isrolling/1,
             hashtable_calc/2]).
 
 -include_lib("eunit/include/eunit.hrl").
@@ -380,6 +381,13 @@ cdb_filename(Pid) ->
 cdb_keycheck(Pid, Key) ->
     gen_fsm:sync_send_event(Pid, {key_check, Key}, infinity).
 
+-spec cdb_isrolling(pid()) -> boolean().
+%% @doc
+%% Check to see if a cdb file is still rolling
+cdb_isrolling(Pid) ->
+    gen_fsm:sync_send_all_state_event(Pid, cdb_isrolling, infinity).
+
+
 %%%============================================================================
 %%% gen_server callbacks
 %%%============================================================================
@@ -744,6 +752,8 @@ handle_sync_event(cdb_firstkey, _From, StateName, State) ->
     {reply, FirstKey, StateName, State};
 handle_sync_event(cdb_filename, _From, StateName, State) ->
     {reply, State#state.filename, StateName, State};
+handle_sync_event(cdb_isrolling, _From, StateName, State) ->
+    {reply, StateName == rolling, StateName, State};
 handle_sync_event(cdb_close, _From, delete_pending, State) ->
     leveled_log:log("CDB05", 
                         [State#state.filename, delete_pending, cdb_close]),

src/leveled_imanifest.erl

@@ -161,6 +161,8 @@ reader(SQN, RootPath) ->
 %% disk
 writer(Manifest, ManSQN, RootPath) ->
     ManPath = leveled_inker:filepath(RootPath, manifest_dir),
+    ok = filelib:ensure_dir(ManPath), 
+        % When writing during backups, may not have been generated
     NewFN = filename:join(ManPath,
                             integer_to_list(ManSQN) ++ "." ++ ?MANIFEST_FILEX),
     TmpFN = filename:join(ManPath,
@@ -198,10 +200,10 @@ complete_filex() ->
     ?MANIFEST_FILEX.
 
 
-%%%============================================================================
+-spec from_list(list()) -> manifest().
-%%% Internal Functions
+%% @doc
-%%%============================================================================
+%% Convert from a flat list into a manifest with lookup jumps.  
-
+%% The opposite of to_list/1
 from_list(Manifest) ->
     % Manifest should already be sorted with the highest SQN at the head
     % This will be maintained so that we can fold from the left, and find
@@ -209,6 +211,11 @@ from_list(Manifest) ->
     % reads are more common than stale reads
     lists:foldr(fun prepend_entry/2, [], Manifest).
 
+
+%%%============================================================================
+%%% Internal Functions
+%%%============================================================================
+
 prepend_entry(Entry, AccL) ->
     {SQN, _FN, _PidR, _LastKey} = Entry,
     case AccL of

src/leveled_inker.erl

@@ -113,6 +113,8 @@
         ink_printmanifest/1,
         ink_close/1,
         ink_doom/1,
+        ink_roll/1,
+        ink_backup/2,
         build_dummy_journal/0,
         clean_testdir/1,
         filepath/2,
@@ -235,10 +237,10 @@ ink_fetch(Pid, PrimaryKey, SQN) ->
 ink_keycheck(Pid, PrimaryKey, SQN) ->
     gen_server:call(Pid, {key_check, PrimaryKey, SQN}, infinity).
 
--spec ink_registersnapshot(pid(), pid()) -> {list(), pid()}.
+-spec ink_registersnapshot(pid(), pid()) -> {list(), pid(), integer()}.
 %% @doc
 %% Register a snapshot clone for the process, returning the Manifest and the
-%% pid of the active journal.
+%% pid of the active journal, as well as the JournalSQN.
 ink_registersnapshot(Pid, Requestor) ->
     gen_server:call(Pid, {register_snapshot, Requestor}, infinity).
 
@@ -389,6 +391,18 @@ ink_compactionpending(Pid) ->
 ink_trim(Pid, PersistedSQN) ->
     gen_server:call(Pid, {trim, PersistedSQN}, infinity).
 
+-spec ink_roll(pid()) -> ok.
+%% @doc
+%% Roll the active journal
+ink_roll(Pid) ->
+    gen_server:call(Pid, roll, infinity).
+
+-spec ink_backup(pid(), string()) -> ok.
+%% @doc
+%% Backup the journal to the specified path
+ink_backup(Pid, BackupPath) ->
+    gen_server:call(Pid, {backup, BackupPath}).
+
 -spec ink_getmanifest(pid()) -> list().
 %% @doc
 %% Allows the clerk to fetch the manifest at the point it starts a compaction
@@ -428,10 +442,12 @@ init([InkerOpts]) ->
         {undefined, true} ->
             SrcInker = InkerOpts#inker_options.source_inker,
             {Manifest,
-                ActiveJournalDB} = ink_registersnapshot(SrcInker, self()),
+                ActiveJournalDB,
+                JournalSQN} = ink_registersnapshot(SrcInker, self()),
             {ok, #state{manifest = Manifest,
                             active_journaldb = ActiveJournalDB,
                             source_inker = SrcInker,
+                            journal_sqn = JournalSQN,
                             is_snapshot = true}};
             %% Need to do something about timeout
         {_RootPath, false} ->
@@ -477,7 +493,8 @@ handle_call({register_snapshot, Requestor}, _From , State) ->
             State#state.manifest_sqn}|State#state.registered_snapshots],
     leveled_log:log("I0002", [Requestor, State#state.manifest_sqn]),
     {reply, {State#state.manifest,
-                State#state.active_journaldb},
+                State#state.active_journaldb,
+                State#state.journal_sqn},
                 State#state{registered_snapshots=Rs}};
 handle_call({confirm_delete, ManSQN}, _From, State) ->
     CheckSQNFun = 
@@ -535,6 +552,56 @@ handle_call(compaction_pending, _From, State) ->
 handle_call({trim, PersistedSQN}, _From, State) ->
     ok = leveled_iclerk:clerk_trim(State#state.clerk, self(), PersistedSQN),
     {reply, ok, State};
+handle_call(roll, _From, State) ->
+    NewSQN = State#state.journal_sqn + 1,
+    {NewJournalP, Manifest1, NewManSQN} = 
+        roll_active(State#state.active_journaldb, 
+                    State#state.manifest, 
+                    NewSQN,
+                    State#state.cdb_options,
+                    State#state.root_path,
+                    State#state.manifest_sqn),
+    {reply, ok, State#state{journal_sqn = NewSQN,
+                                manifest = Manifest1,
+                                manifest_sqn = NewManSQN,
+                                active_journaldb = NewJournalP}};
+handle_call({backup, BackupPath}, _from, State) 
+                                        when State#state.is_snapshot == true ->
+    SW = os:timestamp(),
+    BackupJFP = filepath(filename:join(BackupPath, ?JOURNAL_FP), journal_dir),
+    ok = filelib:ensure_dir(BackupJFP),
+    BackupFun =
+        fun({SQN, FN, PidR, LastKey}, Acc) ->
+            case SQN < State#state.journal_sqn of
+                true ->
+                    BaseFN = filename:basename(FN),
+                    BackupName = filename:join(BackupJFP, BaseFN),
+                    false = when_not_rolling(PidR),
+                    case file:make_link(FN ++ "." ++ ?JOURNAL_FILEX, 
+                                            BackupName ++ "." ++ ?JOURNAL_FILEX) of
+                        ok ->
+                            ok;
+                        {error, eexist} ->
+                            ok
+                    end,
+                    [{SQN, BackupName, PidR, LastKey}|Acc];
+                false ->
+                    leveled_log:log("I0021", [FN, SQN, State#state.journal_sqn]),
+                    Acc
+            end
+        end,
+    BackupManifest = 
+        lists:foldr(BackupFun, 
+                    [], 
+                    leveled_imanifest:to_list(State#state.manifest)),
+    leveled_imanifest:writer(leveled_imanifest:from_list(BackupManifest),
+                                State#state.manifest_sqn, 
+                                filename:join(BackupPath, ?JOURNAL_FP)),
+    leveled_log:log_timer("I0020", 
+                            [filename:join(BackupPath, ?JOURNAL_FP), 
+                                length(BackupManifest)], 
+                            SW),
+    {reply, ok, State};
 handle_call(close, _From, State) ->
     case State#state.is_snapshot of
         true ->
@@ -596,9 +663,9 @@ start_from_file(InkOpts) ->
     % Determine filepaths
     RootPath = InkOpts#inker_options.root_path,
     JournalFP = filepath(RootPath, journal_dir),
-    filelib:ensure_dir(JournalFP),
+    ok = filelib:ensure_dir(JournalFP),
     CompactFP = filepath(RootPath, journal_compact_dir),
-    filelib:ensure_dir(CompactFP),
+    ok = filelib:ensure_dir(CompactFP),
     ManifestFP = filepath(RootPath, manifest_dir),
     ok = filelib:ensure_dir(ManifestFP),
     % The IClerk must start files with the compaction file path so that they
@@ -645,6 +712,19 @@ start_from_file(InkOpts) ->
                     clerk = Clerk}}.
 
 
+when_not_rolling(CDB) ->
+    RollerFun = 
+        fun(Sleep, WasRolling) ->
+            case WasRolling of 
+                false ->
+                    false;
+                true ->
+                    timer:sleep(Sleep),
+                    leveled_cdb:cdb_isrolling(CDB)
+            end
+        end,
+    lists:foldl(RollerFun, true, [0, 1000, 10000, 100000]).
+
 -spec shutdown_snapshots(list(tuple())) -> ok.
 %% @doc
 %% Shutdown any snapshots before closing the store
@@ -710,29 +790,20 @@ put_object(LedgerKey, Object, KeyChanges, State) ->
                 State#state{journal_sqn=NewSQN},
                 byte_size(JournalBin)};
         roll ->
-            SWroll = os:timestamp(),
+            {NewJournalP, Manifest1, NewManSQN} = 
-            LastKey = leveled_cdb:cdb_lastkey(ActiveJournal),
+                roll_active(ActiveJournal, 
-            ok = leveled_cdb:cdb_roll(ActiveJournal),
+                            State#state.manifest, 
-            Manifest0 = leveled_imanifest:append_lastkey(State#state.manifest, 
+                            NewSQN,
-                                                            ActiveJournal,
+                            State#state.cdb_options,
-                                                            LastKey),
-            CDBopts = State#state.cdb_options,
-            ManEntry = start_new_activejournal(NewSQN,
                             State#state.root_path,
-                                                CDBopts),
+                            State#state.manifest_sqn),
-            {_, _, NewJournalP, _} = ManEntry,
-            Manifest1 = leveled_imanifest:add_entry(Manifest0, ManEntry, true),
-            ok = leveled_imanifest:writer(Manifest1,
-                                            State#state.manifest_sqn + 1,
-                                            State#state.root_path),
             ok = leveled_cdb:cdb_put(NewJournalP,
                                         JournalKey,
                                         JournalBin),
-            leveled_log:log_timer("I0008", [], SWroll),
             {rolling,
                 State#state{journal_sqn=NewSQN,
                                 manifest=Manifest1,
-                                manifest_sqn = State#state.manifest_sqn + 1,
+                                manifest_sqn = NewManSQN,
                                 active_journaldb=NewJournalP},
                 byte_size(JournalBin)}
     end.
@@ -756,6 +827,26 @@ get_object(LedgerKey, SQN, Manifest, ToIgnoreKeyChanges) ->
     leveled_codec:from_inkerkv(Obj, ToIgnoreKeyChanges).
 
 
+-spec roll_active(pid(), leveled_imanifest:manifest(), 
+                    integer(), #cdb_options{}, string(), integer()) ->
+                            {pid(), leveled_imanifest:manifest(), integer()}.
+%% @doc
+%% Roll the active journal, and start a new active journal, updating the 
+%% manifest
+roll_active(ActiveJournal, Manifest, NewSQN, CDBopts, RootPath, ManifestSQN) ->
+    SWroll = os:timestamp(),
+    LastKey = leveled_cdb:cdb_lastkey(ActiveJournal),
+    ok = leveled_cdb:cdb_roll(ActiveJournal),
+    Manifest0 = 
+        leveled_imanifest:append_lastkey(Manifest, ActiveJournal, LastKey),
+    ManEntry = 
+        start_new_activejournal(NewSQN, RootPath, CDBopts),
+    {_, _, NewJournalP, _} = ManEntry,
+    Manifest1 = leveled_imanifest:add_entry(Manifest0, ManEntry, true),
+    ok = leveled_imanifest:writer(Manifest1, ManifestSQN + 1, RootPath),
+    leveled_log:log_timer("I0008", [], SWroll),
+    {NewJournalP, Manifest1, ManifestSQN + 1}.
+
 -spec key_check(leveled_codec:ledger_key(), 
                     integer(), 
                     leveled_imanifest:manifest()) -> missing|probably.
@@ -1014,7 +1105,6 @@ sequencenumbers_fromfilenames(Filenames, Regex, IntName) ->
                             [],
                             Filenames).
 
-
 filepath(RootPath, journal_dir) ->
     RootPath ++ "/" ++ ?FILES_FP ++ "/";
 filepath(RootPath, manifest_dir) ->

src/leveled_log.erl

@@ -280,6 +280,10 @@
     {"I0019",
         {info, "After ~w PUTs total prepare time is ~w total cdb time is ~w "
                 ++ "and max prepare time is ~w and max cdb time is ~w"}},
+    {"I0020",
+        {info, "Journal backup completed to path=~s with file_count=~w"}},
+    {"I0021",
+        {info, "Ingoring filename=~s with SQN=~w and JournalSQN=~w"}},
     
     {"IC001",
         {info, "Closed for reason ~w so maybe leaving garbage"}},

test/end_to_end/recovery_SUITE.erl

@@ -2,7 +2,8 @@
 -include_lib("common_test/include/ct.hrl").
 -include("include/leveled.hrl").
 -export([all/0]).
--export([retain_strategy/1,
+-export([hot_backup_simple/1,
+            retain_strategy/1,
             recovr_strategy/1,
             aae_missingjournal/1,
             aae_bustedjournal/1,
@@ -10,6 +11,7 @@
             ]).
 
 all() -> [
+            hot_backup_simple,
             retain_strategy,
             recovr_strategy,
             aae_missingjournal,
@@ -17,6 +19,39 @@ all() -> [
             journal_compaction_bustedjournal
             ].
 
+
+hot_backup_simple(_Config) ->
+    % The journal may have a hot backup.  This allows for an online Bookie
+    % to be sent a message to prepare a backup function, which an asynchronous
+    % worker can then call to generate a backup taken at the point in time
+    % the original message was processsed.
+    %
+    % The basic test is to:
+    % 1 - load a Bookie, take a backup, delete the original path, restore from
+    % that path
+    RootPath = testutil:reset_filestructure(),
+    BookOpts = [{root_path, RootPath},
+                    {cache_size, 1000},
+                    {max_journalsize, 10000000},
+                    {sync_strategy, testutil:sync_strategy()}],
+    {ok, Spcl1, LastV1} = rotating_object_check(BookOpts, "Bucket1", 10000),
+    {ok, Book1} = leveled_bookie:book_start(BookOpts),
+    {async, BackupFun} = leveled_bookie:book_hotbackup(Book1),
+    BackupPath = testutil:reset_filestructure("backup0"),
+    ok = BackupFun(BackupPath),
+    ok = leveled_bookie:book_close(Book1),
+    RootPath = testutil:reset_filestructure(),
+    BookOptsBackup = [{root_path, BackupPath},
+                        {cache_size, 2000},
+                        {max_journalsize, 20000000},
+                        {sync_strategy, testutil:sync_strategy()}],
+    {ok, BookBackup} = leveled_bookie:book_start(BookOptsBackup),
+    ok = testutil:check_indexed_objects(BookBackup, "Bucket1", Spcl1, LastV1),
+    ok = leveled_bookie:book_close(BookBackup),
+    BackupPath = testutil:reset_filestructure("backup0").
+
+
+
 retain_strategy(_Config) ->
     RootPath = testutil:reset_filestructure(),
     BookOpts = [{root_path, RootPath},