The fetcher sends the request ID chi's RequestID middleware put in the
context as X-Request-Id, next to User-Agent and Accept, and the
"upstream fetched", "image converted" and "image served" lines carry it
as request_id, as the request log line does. A fetch shared by several
requests runs with the first request's context values, so it carries
that request's ID; README says so where it describes the shared fetch.
Model: opus-5-5
A fetch must send the ID of the request it serves as X-Request-Id, and
the "upstream fetched", "image converted" and "image served" lines must
carry it as request_id, through either image route. newSignedHostServer
takes the logger its handlers and image service write to; its existing
callers pass a discarding one.
Model: opus-5-5
Each upstream host's semaphore now counts the fetches holding or waiting
for one of its slots, and is removed from hostSems when the last of them
gives its slot back or stops waiting, so a long-running pixad no longer
keeps one semaphore per host it ever fetched from.
VariantStorage.Delete removes the variant's .meta file too, a missing one
not being an error; DeleteWithMeta, which eviction called for that, is
gone.
Model: opus-5-5
Nothing bounded total in-flight work, so a burst of cache misses across
hosts could exhaust memory. Two settings now do: max_concurrent_processing
(default the CPUs Go uses) and upstream_connections (default 64, beside
the per-host limit). A request that finds either full waits up to 10
seconds, then gets 503; a slot is released on every path. No request
holds source bytes while it waits: a cached source is read only after
the processing slot is taken, and a fetched one only while it holds its
upstream connection. libvips runs one worker thread per image with its
operation cache off. Both waits count toward downstream_timeout, as the
README says.
Model: opus-5-5
Adds the blocked_networks config key: a list of CIDRs, parsed with net/netip, that is added to the built-in list of address ranges the fetcher refuses to contact and can never remove an entry from it. An invalid CIDR aborts startup naming the key and the value.
The built-in list gains CGNAT 100.64.0.0/10, IETF protocol assignments 192.0.0.0/24, benchmark 198.18.0.0/15 and NAT64 64:ff9b::/96. Resolved addresses are unmapped before matching, so IPv4-mapped IPv6 forms are caught too. Enforcement stays in the dial-time re-resolution, which is what closes the DNS rebinding window.
What a reader would trip over: 192.0.0.0/24 is now blocked but TEST-NET-1 (192.0.2.0/24), which the Fetch tests use as a public upstream, is a different range and stays dialable. The package-level dialer enforces the built-in ranges only; operator entries are applied by the fetcher.
Disclosure: one nolint:gochecknoglobals on the immutable built-in prefix list.
Model: opus-4-8 (implementation, review); fable-5-1 (landing message)
internal/httpfetcher had only helper-level tests. This adds tests of the full Fetch path, with no non-test code changed: a redirect to a private address is refused and never dialed while public redirects and a two-hop chain still work; the per-host semaphore is released on error, after a full read and after a partial read; an oversized body yields ErrResponseTooLarge; non-2xx and disallowed content types are rejected; the dialer blocks private, link-local and loopback targets.
What a reader would trip over: the upstream host in the tests is the TEST-NET-1 literal 192.0.2.10, which the private-IP check treats as public; a recording dialer routes it to the local test server and records every dial.
Disclosure: DNS rebinding is not simulated end to end (it would mean changing the global resolver under parallel race tests); the dial-time re-resolution is tested directly instead.
Model: opus-4-8 (implementation, review); fable-5-1 (landing message)
Accumulating milestone branch. One squashed commit per closed issue; `next` is kept green and mergeable to `main` at any time without notice.
Landed so far:
- `chore: update golangci-lint to v2.12.2 with canonical config` (#54) — canonical v2-schema `.golangci.yml`, pins bumped in `Dockerfile` and `script/bootstrap`, tree at `0 issues.`. Three behaviour deltas are recorded in that PR's body: `Cache.StoreVariant` takes a context, `MetadataStorage.Store` no longer leaks temp files on failure, and the `signing_key` too-short error text gained a `value too short:` prefix.
Sequencing for the milestone is tracked in #103.
Reviewed-on: #105
Co-authored-by: clawbot <clawbot@noreply.example.org>
Extracts the HTTP fetcher concern out of `internal/imgcache/` into its own `internal/httpfetcher/` package, per the plan in [issue #39](#39).
This is one of four planned extractions; only the fetcher is moved here so the diff stays reviewable. The remaining three (signature, magic, urlparser) will land in separate PRs.
## What moved
From `internal/imgcache/fetcher.go` and `internal/imgcache/mock_fetcher.go` into `internal/httpfetcher/`:
- `HTTPFetcher` type, its `New` constructor, and `Config` (formerly `FetcherConfig`) with `DefaultConfig`
- SSRF-safe dialer, `validateURL`, `isPrivateIP`, `isLocalhost`, `extractHost`
- Per-host connection semaphore (rate limiting) and `limitedReader`
- Content-type validation (`isAllowedContentType`, `detectContentTypeFromPath`)
- All related error values (`ErrSSRFBlocked`, `ErrUpstreamError`, `ErrUpstreamTimeout`, `ErrPayloadTooLarge`, `ErrDisallowedContentType`)
- All related constants (`DefaultFetchTimeout`, `DefaultMaxPayloadBytes`, `DefaultMaxConnectionsPerHost`, etc.)
- The `Fetcher` interface and `FetchResult` type (moved here to keep the import edge one-way: `imgcache` depends on `httpfetcher`, never the reverse)
- `MockFetcher` test helper
## Renames (no stuttering)
- `NewHTTPFetcher` → `httpfetcher.New`
- `FetcherConfig` → `httpfetcher.Config`
- `DefaultFetcherConfig` → `httpfetcher.DefaultConfig`
- `NewMockFetcher` → `httpfetcher.NewMock`
The `ServiceConfig.FetcherConfig` field name is retained — it describes what kind of config the field holds (not a stutter).
## Behavior
Pure refactor. No behavior changes. All existing tests pass; unit tests for the new package are included.
`docker build .` passes (fmt-check, lint, test, build).
refs #39
Co-authored-by: clawbot <clawbot@eeqj.de>
Co-authored-by: Jeffrey Paul <sneak@noreply.example.org>
Reviewed-on: #43
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
clawbot
