feat(cache): support byte ranges on Cache.Open#345
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Add Range/If-Range support to Cache.Open mirroring the existing ETag conditional pattern. RequestOptions gains Range/IfRange fields and a ResolveRange resolver for a single byte range, gated on the stored ETag via If-Range. Backends slice the body (disk seek, memory slice, S3 ranged GET) and set Content-Range; out-of-bounds ranges return ErrRangeNotSatisfiable. Tiered skips backfill on partial reads to avoid caching truncated objects. Serving emits 206/416 and advertises Accept-Ranges; Stat ignores Range. Multi-range falls back to a full 200. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Address code-review findings on the byte-range support: - Strip Range, If-Range and Content-Range on PUT (httputil.TransportHeaders), alongside the existing If-Match/If-None-Match. A stored Content-Range would otherwise be replayed and make a plain GET spuriously answer 206. - Return the stored headers (not nil) on the disk Seek error path, matching the 416 path. - Add tests: stored-Content-Range regression, full-size and suffix Content-Length assertions, and a zero-length-object 416 case. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Replace the raw-string Range(spec) option with a typed Range(start, end) taking a half-open byte interval; a negative end means "to the end of the object" (Content-Length). e.g. Range(0, 500) is the first 500 bytes and Range(0, -1) the whole object. The raw HTTP header form is retained as RangeHeader(spec) for forwarding a client's Range verbatim (used by httputil and for suffix ranges that the typed form can't express). The wire format and server-side parsing are unchanged. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The client SDK targets the apiv1 endpoint and only needs the typed Range(start, end) form, so remove the raw RangeHeader option (and its cache re-export). The server's proxy handlers still forward an external client's verbatim Range header (e.g. suffix "bytes=-N") by setting the shared RequestOptions.Range field directly in httputil. Suffix coverage stays via the existing apiv1 end-to-end test; the redundant suite subtest is removed. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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| headers.Set("Content-Range", fmt.Sprintf("bytes */%d", size)) | ||
| return 0, 0, false, ErrRangeNotSatisfiable |
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In this RangeNotSatisfiable branch, headers already contains the full object's Content-Length because each backend sets it before calling rangeShortCircuit. ServeCacheHit copies these headers for a 416 response and writes no body, so an out-of-bounds Range request advertises bytes that are never sent, which can make HTTP clients hang or report an unexpected EOF. Clear Content-Length or set it to the actual 416 body length/0 before returning the error.
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Summary
Adds single byte-range support to
Cache.Open, mirroring the existing ETag conditional-request pattern end to end (client SDK → cache backends → server serving → remote wire).client.Range(start, end int64)— a typed, half-open[start, end)byte range; a negativeendmeans "to the end of the object". e.g.Range(0, 500)is the first 500 bytes,Range(0, -1)the whole object. Out-of-bounds ranges returnErrRangeNotSatisfiable.io.LimitReader, memory slices, S3 issues a single ranged GET (pinned to the object ETag), Remote forwards over the wire.Tieredskips backfill on partial reads so a truncated object is never cached.httputil) emits206 Partial Content/416 Range Not Satisfiable, advertisesAccept-Ranges: bytes, and forwards an external client's verbatimRangeheader (incl. suffixbytes=-N) on the proxy handlers.Stat/HEAD ignores Range.Range,If-Range,Content-Range) are stripped on PUT so they can't be stored and replayed.Deliberate scope
Rangeheaders fall back to a full200.If-Rangesupports the entity-tag form only (compared against the stored ETag).Test plan
client:Rangeformatting,ResolveRangeparser edge cases, 206/416 wire mapping.cachetestconformance suite: partial/full/416/If-Range-mismatch/Stat-ignores-Range across all backends (disk, memory, S3, tiered, remote).strategy/apiv1: end-to-end 206/416, suffix range, multi-range fallback, If-Range, HEAD-ignores-Range, and a stored-Content-Rangeregression test.go test,go vet, andgolangci-lintclean.🤖 Generated with Claude Code