Figure out larger file support (up to 5GB)

apps/maestro/test/session_SUITE_data/others/a.toml

@@ -9,7 +9,7 @@
 [server]
     [server.auth.tls]
     # status = "disabled"
-    port = 8022
+    port = 8822
     certfile = "./others/certs/a.crt"
     keyfile = "./others/certs/a.key"
     [server.auth.tls.authorized]

apps/maestro/test/session_SUITE_data/others/a_switch.toml

@@ -9,7 +9,7 @@
 [server]
     [server.auth.tls]
     # status = "disabled"
-    port = 8022
+    port = 8822
     certfile = "./others/certs/a.crt"
     keyfile = "./others/certs/a.key"
     [server.auth.tls.authorized]
@@ -21,7 +21,7 @@
 [peers]
   [peers.b]
   sync = ["test"]
-  url = "127.0.0.1:8023"
+  url = "127.0.0.1:8823"
     [peers.b.auth]
     type = "tls"
     certfile = "./others/certs/a.crt"

apps/maestro/test/session_SUITE_data/others/b.toml

@@ -9,7 +9,7 @@
 [peers]
   [peers.a]
   sync = ["test"]
-  url = "127.0.0.1:8022"
+  url = "127.0.0.1:8822"
     [peers.a.auth]
     type = "tls"
     certfile = "./others/certs/b.crt"

apps/maestro/test/session_SUITE_data/others/b_switch.toml

@@ -9,7 +9,7 @@
 [peers]
   [peers.a]
   sync = ["test"]
-  url = "127.0.0.1:8022"
+  url = "127.0.0.1:8822"
     [peers.a.auth]
     type = "tls"
     certfile = "./others/certs/b.crt"
@@ -19,7 +19,7 @@
 [server]
     [server.auth.tls]
     # status = "disabled"
-    port = 8023
+    port = 8823
     certfile = "./others/certs/b.crt"
     keyfile = "./others/certs/b.key"
     [server.auth.tls.authorized]

apps/revault/src/revault.app.src

@@ -18,7 +18,8 @@
     aws, jsx
   ]},
   {env, [
-    {backend, disk}
+    {backend, disk},
+    {multipart_size, 52428800} % 50MiB
   ]},
   {modules, []},
 

apps/revault/src/revault_data_wrapper.erl

@@ -10,10 +10,12 @@
 %%% protocol here does not need to know where or how.
 -module(revault_data_wrapper).
 -export([peer/1, peer/2, new/0, ask/0, ok/0, error/1, fork/2]).
--export([manifest/0, manifest/1, send_file/4, send_deleted/2,
-         send_conflict_file/5, fetch_file/1,
+-export([manifest/0, manifest/1,
+         send_file/4, send_multipart_file/6, send_deleted/2,
+         send_conflict_file/5, send_conflict_multipart_file/7, fetch_file/1,
          sync_complete/0]).
--define(VSN, 1).
+
+-include("revault_data_wrapper.hrl").
 
 peer(Remote) ->
     {peer, ?VSN, Remote}.
@@ -36,12 +38,58 @@ manifest(Data) ->
 send_file(Path, Vsn, Hash, Bin) ->
     {file, ?VSN, Path, {Vsn, Hash}, Bin}.
 
+%% @private send_multipart_file/6 is special in that it implies an ordering
+%% between all calls for breaking down large file uploads.
+%%
+%% A new multipart transfer is defined with the `PartNum' value `1'. All
+%% subsequent calls must get an incrementing `PartNum' in order, with no gap,
+%% until `PartNum =:= PartTotal', which signals that the last part of the file
+%% has been received and the write can be considered complete.
+%%
+%% This API is a choice that allows transferring sequentially to disk, or in
+%% parallel in some S3 upload. In picking the lowest common denominator, we
+%% expect sequential transfers, such that a file on disk can be continuously
+%% appended.
+%%
+%% The `Hash' value sent is expected to be repeated every time, and is the hash
+%% of the final transfer. This is because ReVault does not have any sort of
+%% file locking mechanism, and expecting the same hash from beginning to end
+%% allows us to detect if the source file has been modified during the
+%% transfer, and ignore the result upon the final saving.
+%%
+%% TODO: this interface is different from the conflict file mechanism which uses
+%% a decrementing counter. We might want to align the conflict file mechanism
+%% at some point.
+-spec send_multipart_file(Path, Vsn, Hash, PartNum, PartTotal, binary()) ->
+        {file, ?VSN, Path, {Vsn, Hash}, PartNum, PartTotal, binary()}
+           when Path :: file:filename(),
+                Vsn :: revault_dirmon_tracker:stamp(),
+                Hash :: revault_file:hash(),
+                PartNum :: 1..10000,
+                PartTotal :: 1..10000.
+send_multipart_file(Path, Vsn, Hash, M, N, Bin) when M >= 1, M =< N ->
+    {file, ?VSN, Path, {Vsn, Hash}, M, N, Bin}.
+
 send_deleted(Path, Vsn) ->
     {deleted_file, ?VSN, Path, {Vsn, deleted}}.
 
 send_conflict_file(WorkPath, Path, ConflictsLeft, Meta, Bin) ->
     {conflict_file, ?VSN, WorkPath, Path, ConflictsLeft, Meta, Bin}.
 
+%% TODO: figure out if we need a way to work around conflict candidate files
+%% having hashes modified from under us during the transfer
+-spec send_conflict_multipart_file(WorkPath, Path, ConflictsLeft, Meta, PartNum, PartTotal, binary()) ->
+        {conflict_multipart_file, ?VSN, WorkPath, Path, ConflictsLeft, Meta, PartNum, PartTotal, binary()}
+           when WorkPath :: file:filename(),
+                Path :: file:filename(),
+                ConflictsLeft :: non_neg_integer(),
+                Meta :: {revault_dirmon_tracker:stamp(),
+                         revault_file:hash() | {conflict, [revault_file:hash()], revault_file:hash()}},
+                PartNum :: 1..10000,
+                PartTotal :: 1..10000.
+send_conflict_multipart_file(WorkPath, Path, ConflictsLeft, Meta, PartNum, PartTotal, Bin) ->
+    {conflict_multipart_file, ?VSN, WorkPath, Path, ConflictsLeft, Meta, PartNum, PartTotal, Bin}.
+
 fetch_file(Path) ->
     {fetch, ?VSN, Path}.
 

apps/revault/src/revault_data_wrapper.hrl

@@ -0,0 +1,4 @@
+% VSN 1: initial protocol
+% VSN 2: adds multipart file transfers
+% TODO: add test about protocol compatibility
+-define(VSN, 2).

apps/revault/src/revault_disterl.erl

@@ -14,7 +14,9 @@
 %%% converters to deal with various encodings and wire formats.
 -module(revault_disterl).
 -export([callback/1, mode/1, peer/3, accept_peer/2, unpeer/2, send/2, reply/3, unpack/1]).
--define(VSN, 1).
+
+-include("revault_data_wrapper.hrl").
+
 -type state() :: ?MODULE.
 -export_type([state/0]).
 
@@ -77,11 +79,14 @@ unpack({error, ?VSN, R}) -> {error, R};
 unpack({manifest, ?VSN}) -> manifest;
 unpack({manifest, ?VSN, Data}) -> {manifest, Data};
 unpack({file, ?VSN, Path, Meta, Bin}) -> {file, Path, Meta, Bin};
+unpack({file, ?VSN, Path, Meta, PartNum, PartTotal, Bin}) -> {file, Path, Meta, PartNum, PartTotal, Bin};
 unpack({fetch, ?VSN, Path}) -> {fetch, Path};
 unpack({sync_complete, ?VSN}) -> sync_complete;
 unpack({deleted_file, ?VSN, Path, Meta}) -> {deleted_file, Path, Meta};
 unpack({conflict_file, ?VSN, WorkPath, Path, Count, Meta, Bin}) ->
     {conflict_file, WorkPath, Path, Count, Meta, Bin};
+unpack({conflict_multipart_file, ?VSN, WorkPath, Path, Count, Meta, PartNum, PartTotal, Bin}) ->
+    {conflict_multipart_file, WorkPath, Path, Count, Meta, PartNum, PartTotal, Bin};
 unpack(Term) ->
     Term.
 

apps/revault/src/revault_file.erl

@@ -3,13 +3,19 @@
          make_relative/2,
          copy/2,
          tmp/0, tmp/1, extension/2,
-         find_hashes/2,
+         find_hashes/2, size/1,
+         read_range/3,
+         multipart_init/3, multipart_update/6, multipart_final/4,
          %% wrappers to file module
          delete/1, consult/1, read_file/1, ensure_dir/1, is_regular/1,
          write_file/2, write_file/3, rename/2]).
 
 -type hash() :: binary().
--export_type([hash/0]).
+-type multipart_state() :: {state,
+                            file:filename(),
+                            non_neg_integer(), pos_integer(),
+                            hash(), term()}.
+-export_type([hash/0, multipart_state/0]).
 
 %% @doc takes a file and computes a hash for it as used to track changes
 %% in ReVault. This hash is not guaranteed to be stable, but at this time
@@ -93,6 +99,43 @@ extension(Path, Ext) when is_binary(Path) ->
 find_hashes(Dir, Pred) ->
     (mod()):find_hashes(Dir, Pred).
 
+-spec size(file:filename()) -> {ok, non_neg_integer()} | {error, term()}.
+size(Path) ->
+    (mod()):size(Path).
+
+-spec read_range(Path, Offset, Bytes) -> {ok, binary()} | {error, term()} when
+      Path :: file:filename(),
+      Offset :: non_neg_integer(),
+      Bytes :: pos_integer().
+read_range(Path, Offset, Bytes) ->
+    (mod()):read_range(Path, Offset, Bytes).
+
+-spec multipart_init(Path, PartsTotal, Hash) -> State when
+    Path :: file:filename(),
+    PartsTotal :: pos_integer(),
+    Hash :: hash(),
+    State :: multipart_state().
+multipart_init(Path, PartsTotal, Hash) ->
+    (mod()):multipart_init(Path, PartsTotal, Hash).
+
+-spec multipart_update(multipart_state(), Path, PartNum, PartsTotal, Hash, binary()) ->
+    {ok, multipart_state()} when
+        Path :: file:filename(),
+        PartNum :: 1..10000,
+        PartsTotal :: 1..10000,
+        Hash :: hash().
+multipart_update(State={state, Path, PartsSeen, PartsTotal, Hash, _Term},
+                 Path, PartNum, PartsTotal, Hash, Bin) when PartNum =:= PartsSeen+1 ->
+    (mod()):multipart_update(State, Path, PartNum, PartsTotal, Hash, Bin).
+
+-spec multipart_final(multipart_state(), Path, PartsTotal, Hash) -> ok when
+    Path :: file:filename(),
+    PartsTotal :: pos_integer(),
+    Hash :: hash().
+multipart_final(State={state, Path, PartsSeen, PartsTotal, Hash, _Term},
+                Path, PartsTotal, Hash) when PartsSeen =:= PartsTotal ->
+    (mod()):multipart_final(State, Path, PartsTotal, Hash).
+
 %%%%%%%%%%%%%%%%%%%%%
 %%% FILE WRAPPERS %%%
 %%%%%%%%%%%%%%%%%%%%%

apps/revault/src/revault_file_disk.erl

@@ -1,8 +1,13 @@
 -module(revault_file_disk).
+
+-include_lib("kernel/include/file.hrl").
+
 -export([hash/1, hash_bin/1,
          copy/2,
          tmp/0, tmp/1,
-         find_hashes/2,
+         find_hashes/2, size/1,
+         read_range/3,
+         multipart_init/3, multipart_update/6, multipart_final/4,
          %% wrappers to file module
          delete/1, consult/1, read_file/1, ensure_dir/1, is_regular/1,
          write_file/2, write_file/3, rename/2]).
@@ -15,6 +20,7 @@
 %% it is SHA256.
 -spec hash(file:filename_all()) -> hash().
 hash(Path) ->
+    %% TODO: support large files on this too
     {ok, Bin} = read_file(Path),
     hash_bin(Bin).
 
@@ -82,6 +88,69 @@ find_hashes(Dir, Pred) ->
       []
     ).
 
+-spec size(file:filename()) -> {ok, non_neg_integer()} | {error, term()}.
+size(Path) ->
+    maybe
+        {ok, Rec} ?= file:read_file_info(Path),
+        {ok, Rec#file_info.size}
+    end.
+
+-spec read_range(Path, Offset, Bytes) -> {ok, binary()} | {error, term()} when
+      Path :: file:filename(),
+      Offset :: non_neg_integer(),
+      Bytes :: pos_integer().
+read_range(Path, Offset, Bytes) ->
+    maybe
+        {ok, Fd} ?= file:open(Path, [read, raw, binary]),
+        Res = file:pread(Fd, Offset, Bytes),
+        file:close(Fd),
+        case Res of
+            {ok, Bin} when byte_size(Bin) =:= Bytes -> Res;
+            {error, _} -> Res;
+            {ok, Bin} when byte_size(Bin) =/= Bytes -> {error, invalid_range};
+            eof -> {error, invalid_range}
+        end
+    end.
+
+-spec multipart_init(Path, PartsTotal, Hash) -> State when
+    Path :: file:filename(),
+    PartsTotal :: pos_integer(),
+    Hash :: revault_file:hash(),
+    State :: revault_file:multipart_state().
+multipart_init(Path, PartsTotal, Hash) ->
+    {ok, Fd} = file:open(Path, [raw, write]),
+    HashState = crypto:hash_init(sha256),
+    {state, Path, 0, PartsTotal, Hash,
+     {Fd, HashState}}.
+
+-spec multipart_update(State, Path, PartNum, PartsTotal, Hash, binary()) ->
+    {ok, revault_file:multipart_state()} when
+        State :: revault_file:multipart_state(),
+        Path :: file:filename(),
+        PartNum :: 1..10000,
+        PartsTotal :: 1..10000,
+        Hash :: revault_file:hash().
+multipart_update({state, Path, _PartsSeen, PartsTotal, Hash,
+                  {Fd, HashState}},
+                 Path, PartNum, PartsTotal, Hash, Bin) ->
+    ok = file:write(Fd, Bin),
+    NewHashState = crypto:hash_update(HashState, Bin),
+    {ok, {state, Path, PartNum, PartsTotal, Hash, {Fd, NewHashState}}}.
+
+-spec multipart_final(State, Path, PartsTotal, Hash) -> ok when
+        State :: revault_file:multipart_state(),
+    Path :: file:filename(),
+    PartsTotal :: pos_integer(),
+    Hash :: revault_file:hash().
+multipart_final({state, Path, _PartsSeen, PartsTotal, Hash,
+                 {Fd, HashState}},
+                Path, PartsTotal, Hash) ->
+    ok = file:close(Fd),
+    case crypto:hash_final(HashState) of
+        Hash -> ok;
+        _BadHash -> error(invalid_hash)
+    end.
+
 %%%%%%%%%%%%%%%%%%%%%
 %%% FILE WRAPPERS %%%
 %%%%%%%%%%%%%%%%%%%%%