Bound HTTP fetcher memory use under load - #74
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The HTTP fetcher read each download fully into memory (io.ReadAll) before storing it in the CAS, so large numbers of parallel fetches could cause OOMs. Two changes address this: - When the blob's digest is known up front (a checksum.sri using the request's digest function, plus a Content-Length), the response is streamed straight to the CAS without being buffered at all. - Otherwise the body has to be read to compute the digest. This is still buffered in memory by default, but the new download_directory_path option buffers it in a temporary file on disk instead.
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Closing in favour of #75 |
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The HTTP fetcher read each download fully into memory (io.ReadAll) before storing it in the CAS, so large numbers of parallel fetches could cause OOMs.
Two changes address this:
This was written with Claude but I've carefully reviewed it all and tested it end to end locally.