The /skewt page was empty in prod because Phase 2 of the Rust cutover
moved f01..f18 grid scoring to Rust but left profile-file writing only
on the analysis (f00) path. Result: /data/scores/profiles/ accumulated
one file per chain run instead of nineteen, so SkewtLive only ever saw
the analysis hour — and that hour falls outside the 1 h past cutoff
within an hour of the chain finishing, leaving the page empty most of
the time.
Two surgical fixes:
* `pipeline::run_chain_step` now builds `profile_entries` alongside
`prepared` from the merged grid in a single iter pass, then spawns
`profiles_file::write_atomic` on the blocking pool to overlap the
NFS write with the score-band scoring/write fan-out — same pattern
`run_analysis_step` already uses. `ChainStepStats` gains
`profile_cells_written` so the worker log line is symmetric with
the analysis step's existing field and a future failure mode that
drops the profile would show up as a divergence.
* `SkewtLive.available_valid_times/0` widens the past cutoff from
1 h to 3 h. The chain's analysis hour can be ~70 min old by the
time the next chain finishes (and ~2 h on a missed cycle), so the
1 h cutoff was leaving the page blank during normal transients.
18 h forward window unchanged.
Cosmetic: cargo fmt picked up trivial rewrites in decoder/fetcher/
native_duct/hrrr_point_worker that had drifted; rolled in.
Verification: cargo build --release, cargo clippy --lib --bins -D
warnings, cargo test --lib (134/134), mix test
test/microwaveprop_web/live/skewt_live_test.exs (3/3) all green.
The decoder's `parse_lola_binary` inserts the same "VAR:LEVEL"
string into ~92k cell maps for every one of ~60 GRIB2 messages in
a chain step — previously a String::clone per cell, yielding
~5.5M heap allocations and frees per hourly run. Switching
`CellValues` from `HashMap<String, f32>` to
`HashMap<Arc<str>, f32>` makes each insertion a single atomic
refcount increment: the string is allocated once per message, and
`Arc::clone` is cheap from there.
Callers were mostly unchanged — `cell.get("...")` still works via
`Arc<str>: Borrow<str>`. Two touch-ups needed: native_duct.rs had
a couple of `cell.get(&format!(...))` lookups that were passing
`&String` (triggering the wrong Borrow impl) — switched to
.as_str(), and the test fixtures' `.insert(format!(...), _)` now
need a `.into()` to coerce into `Arc<str>`. Zero behavior change.
Root cause of the blank /map analysis breakdown: the skippy.w5isp.com
caching proxy was unreachable from the cluster, so every f00 analysis
step failed at the idx fetch and Rust never wrote a ProfilesFile. The
/map point-detail panel silently degraded to empty factors because
no profile ever lands on `/data/scores/profiles/`.
HrrrClient now takes an optional fallback base. When the primary base
exhausts its retries (5× exponential backoff), fetches retry once
against the fallback — defaulted to the NOAA S3 public bucket. Forecast,
analysis, and native-duct paths all go through the same
fetch_blob_with_fallback helper so a proxy outage degrades to direct
S3 instead of stalling.
Moved the native-URL builder out of native_duct into fetcher so the
single helper can build both primary and fallback URLs for the native
hybrid-sigma product.
native_duct.rs is the Rust side of HrrrNativeClient.fetch_native_duct_grid:
fetch native-level HRRR idx → select duct byte ranges (TMP/SPFH/HGT/PRES
× 50 hybrid levels = 200 messages, ~300 MB subset) → wgrib2 decode via
the existing decoder::extract_grid plumbing → per-cell build_native_profile
→ duct::analyze → HashMap<(lat, lon), DuctMetrics>.
build_native_profile keeps the Elixir semantics intact: drop cells that
don't reach 3 levels, sort by ascending height, tolerate missing SPFH/PRES
as zero (the duct math handles zeros gracefully). merge_duct_grid gives
the pipeline.rs caller a drop-in replacement for Elixir's apply_duct_grid.
claim_next_analysis is the analysis-lane companion to claim_next: selects
kind='analysis' rows only, same SKIP LOCKED + newest-first ordering. Kept
on a separate claim function so the forecast lane can keep running
unaffected during cutover; the analysis pipeline wiring lands next.
9 pure unit tests cover message generation, URL builder, profile-sort,
min-level filter, and merge-into-base behaviour. Network-live golden
against a real native GRIB2 deferred to the cutover commit.
