f7358424e4
* maybe_gc/2 is triggered at machi_file_proxy, when chunk is deleted
and the file is larger than `max_file_size`
* A file is deleted if all chunks except 1024 bytes header are trimmed
* If a file is going to be deleted, file_proxy notifies metadata_mgr
to remember the filename persistently, whose filename is
`known_files_<FluName>`
* Such trimmed filenames are stored in a machi_plist file per flu
* machi_file_proxy could not be started if the filename is in the
manager's list. Consequently, any write, read and trim operations
cannot happen against deleted file.
* After the file was trimmed, any read request to the file returns
`{error, trimmed}`
* Disclaimer: no tests written yet and machi_plist does not support
any recovery from partial writes.
* Add some thoughts as comments for repairing trims.
* State diagram of every byte is as follows:
```
state\action| write/append | read_chunk | trim_chunk
------------+----------------+------------------+---------------
unwritten | -> written | fail (+repair) | -> trimmed
written | noop or repair | return content | -> trimmed
trimmed | fail | fail | noop
```
17 lines
524 B
Erlang
17 lines
524 B
Erlang
-module(machi_plist_test).
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-include_lib("eunit/include/eunit.hrl").
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open_close_test() ->
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FileName = "bark-bark-one",
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file:delete(FileName),
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{ok, PList0} = machi_plist:open(FileName, []),
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{ok, PList1} = machi_plist:add(PList0, "boomar"),
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?assertEqual(["boomar"], machi_plist:all(PList1)),
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ok = machi_plist:close(PList1),
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{ok, PList2} = machi_plist:open(FileName, []),
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?assertEqual(["boomar"], machi_plist:all(PList2)),
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ok = machi_plist:close(PList2),
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file:delete(FileName),
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ok.
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