Summary:
Ref T7149. This isn't complete and isn't active yet, but does basically work. I'll shore it up in the next few diffs.
The new workflow goes like this:
> Client, file.allocate(): I'd like to upload a file with length L, metadata M, and hash H.
Then the server returns `upload` (a boolean) and `filePHID` (a PHID). These mean:
| upload | filePHID | means |
|---|---|---|
| false | false | Server can't accept file.
| false | true | File data already known, file created from hash.
| true | false | Just upload normally.
| true | true | Query chunks to start or resume a chunked upload.
All but the last case are uninteresting and work like exising uploads with `file.uploadhash` (which we can eventually deprecate).
In the last case:
> Client, file.querychunks(): Give me a list of chunks that I should upload.
This returns all the chunks for the file. Chunks have a start byte, an end byte, and a "complete" flag to indicate that the server already has the data.
Then, the client fills in chunks by sending them:
> Client, file.uploadchunk(): Here is the data for one chunk.
This stuff doesn't work yet or has some caveats:
- I haven't tested resume much.
- Files need an "isPartial()" flag for partial uploads, and the UI needs to respect it.
- The JS client needs to become chunk-aware.
- Chunk size is set crazy low to make testing easier.
- Some debugging flags that I'll remove soon-ish.
- Downloading works, but still streams the whole file into memory.
- This storage engine is disabled by default (hardcoded as a unit test engine) because it's still sketchy.
- Need some code to remove the "isParital" flag when the last chunk is uploaded.
- Maybe do checksumming on chunks.
Test Plan:
- Hacked up `arc upload` (see next diff) to be chunk-aware and uploaded a readme in 18 32-byte chunks. Then downloaded it. Got the same file back that I uploaded.
- File UI now shows some basic chunk info for chunked files:
{F336434}
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: joshuaspence, epriestley
Maniphest Tasks: T7149
Differential Revision: https://secure.phabricator.com/D12060
