perf(ai-proxy): optimize SSE decoder - remove PCRE, add decode_buf, fix comment lines#13391
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perf(ai-proxy): optimize SSE decoder - remove PCRE, add decode_buf, fix comment lines#13391AlinsRan wants to merge 1 commit into
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…ix comment lines - Replace ngx_re.split (PCRE) in sse.decode() with a pure Lua forward scan. Avoids regex compilation and PCRE overhead on every streaming chunk. - Add sse.decode_buf(buf) that combines split_buf + decode into a single O(n) forward pass, halving the number of scans per chunk in hot paths. - Fix SSE comment lines (lines starting with ':') being incorrectly treated as fields. Per the SSE spec, comment lines must be silently ignored; the previous code set has_field=true for them, producing spurious empty events. - Add test: SSE comment lines are correctly discarded by decode_buf. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Summary
1. Remove PCRE dependency from SSE decoder
Replace
ngx_re.split(PCRE) insse.decode()with a pure Lua forward scan (string.find).Benefit: Eliminates regex compilation overhead on each streaming chunk. PCRE calls are expensive because they allocate JIT memory; replacing them with
string.findreduces per-chunk CPU cost and memory allocations in high-throughput SSE streams.2. Add
decode_buf(buf)- single-pass buffer decodingNew function that combines
split_buf+decodeinto one O(n) forward pass, returning(events, remainder).Benefit: The current hot path calls
split_bufthendecode, scanning the buffer twice.decode_bufdoes both in one pass, halving scan work per chunk. Callers that only need the combined result can use this directly.3. Fix SSE comment lines being treated as fields
SSE lines starting with
:are comment lines per the SSE spec. The previousdecode()used a regex that skipped lines without a named field but the new implementation correctly identifiescolon == 1as a comment and skips it without settinghas_field = true, which previously caused comment-only blocks to be emitted as empty events.Benefit: Correct spec compliance. Some providers (e.g., keep-alive pings sent as
: keep-alive) would produce spurious empty events before this fix.Test
Added TEST 29 in
t/plugin/ai-proxy-protocol-conversion.t: SSE comment lines interleaved with real events are correctly discarded bydecode_buf.