Dcerl is a Porting library of DiskLruCache for Erlalng. Main goals of this product are described below.
-
SSD-Aware: Enable to specify separate paths for Data files(on SSD) and the journal file(on HDD). -
S3 Compatible: Enable a key to use a sequence of Unicode characters(UTF8). -
Concurrency: Enable to execute by a Erlang process. -
Reduce complexities: Get rid of rarely used functions like multi values per a key. -
Expand Usecases: Provide chunked(split) data interfaces to handle very large files.
Erlang >= R14B
make
erl -pa ebin
%% on Erlang REPL
{ok, DS} = dcerl_api:start(DataDir, JournalDir, MaxSize, MaxChunkSize),
{ok, DS2} = dcerl_api:put(DS, BinKey, BinBody), %% normal put
{ok, DS3} = dcerl_api:remove(DS2, BinKey), %% remove
{ok, DS4, FD} = dcerl_api:put_begin(DS3, BinKey), %% chunked put
ok = dcerl_api:put_chunk(DS4, FD, Chunk1),
ok = dcerl_api:put_chunk(DS4, FD, Chunk2),
ok = dcerl_api:put_chunk(DS4, FD, Chunk3),
{ok, DS5} = dcerl_api:put_end(DS4, FD, true), %% commit
%%{ok, DS5} = dcerl_api:put_end(DS4, FD, false), %% abort
case dcerl:get(DS5, BinKey) of
{ok, DS6, #dcerl_fd{tmp_datafile_iodev = IoDev} = FD2} ->
%% chunked get
%% got the wrapped FD record
%% call `get_chunk` until the last of returned parameter become `true`
void;
{ok, DS6, Bin} ->
%% normal get
%% got the whole Data
void;
_ -> void
end,
dcerl_api:delete(DS6), %% delete all of cache files AND a journal file