docs(observe): OTLP/HTTP gzip and the X-Project-Name header [TH-8743] [TH-8744] - #1028

…TH-8743] [TH-8744]

- gRPC stays uncompressed: keep compression: none on the Collector otlp exporter.
- Content-Encoding must match the body; other codings are 415.
- A busy collector answers gzip requests 503 with Retry-After: 1.
- The header example sets OTEL_EXPORTER_OTLP_TRACES_PROTOCOL=http/protobuf.
- Header values over 255 characters or with control characters are 400.
- The lazy-check note covers every header check; the header is trimmed.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

…43] [TH-8744]

Document the 16 MiB OTLP/HTTP limit after decompression (no separate gzip
wire-size cap), the gzip reservation lifecycle and exact budget scope, the
10,000-level message/JSON guard, and the TH-8745 decode-amplification follow-up.
Document per-resource project precedence, auth-disabled compatibility, RFC
9110 rejection of repeated/comma-joined header values, and Unicode Cf rejection.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

…r characters [TH-8743] [TH-8744]

- The 16 MiB limit applies to the body as sent and, for gzip, again
  after decompression, as the OpenTelemetry Collector applies
  max_request_body_size. Drop "the compressed wire stream has no
  separate size cap".
- A gzip request takes its decompressed size from the budget only after
  it has been received in full; say what that means for concurrency.
- The nesting limit covers OTLP/gRPC too (INTERNAL).
- Line/paragraph separators and default-ignorable characters in
  X-Project-Name are a 400.
- Note that earlier collectors ignored Content-Encoding.
- Remove internal ticket references from the public page.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

…[TH-8743]

The gzip request is read in full before taking a budget share, but the
count/inflate pass must be budgeted too. Document the 16 MiB initial
reservation after upload, its shrink to the exact decompressed size, and
the fact that both inflate passes—but not the network upload—are under
the lease. Explain that small bodies release unused budget after counting.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

…cket [TH-8743]

Clarify that the 16 MiB body limit and gzip decompressed-byte budget do
not limit allocations caused by decoding element-heavy requests, and that
hardening for that is planned separately. Keep internal issue IDs off the
public page.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

The busy-collector bullet now says what an exporter sees: a gzip request
takes its share only after it is received in full, waits up to 2 s, then
gets 503 + Retry-After. The self-hosted note keeps the FI_GZIP_INFLIGHT_MIB
sizing in plain terms. The sentence about planned decode-cost work is
removed; the page describes shipped behaviour only.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

The project-header table now lists a value with no visible character
(only combining marks, or symbols that display as blank space such as
U+2800) as rejected with 400 / INVALID_ARGUMENT. The self-hosted note says
the gzip budget counts decompressed body bytes only and to size the
collector's memory limit as for uncompressed requests.

Co-Authored-By: Claude Opus 5.5 <[email protected]>