Go-parity audit: lagotto-ts vs lagotto (tracking)

[scttfrdmn]

Tracking issue holding the command-by-command parity classification against Go lagotto. Filed because "parity" had never been written down anywhere: this repo had zero issues and zero milestones, so nothing distinguished a deliberate omission from an oversight.

Headline

Go is ~6,858 non-test lines across 11 commands; lagotto-ts is 699 lines across 10 files. The gap is real but concentrated, and the audit overturned the expected verdict on its biggest piece (persistence — see #4).

Command tiers

Go command	tier	where
watch (create)	B	the matching is ported (evaluate, compilePattern, azs, duration); creating a persisted watch needs #4
poll	A/B	CapacityWatcher.check/poll ports searchBestMatch faithfully — but see #1 (regions)
list	B	#4
status <id>	B	#4
cancel <id>	B	#4 — note the Go version also releases an active ODCR (Holder.Release) so it stops billing
extend <id>	B	#4 (ExtendWatch, incl. the reactivate path)
history	B	#4
launch --at/--after/--cron	B	#3 (pure expression) + Scheduler is CORS-open
setup	D/E	creates DynamoDB tables — provisioning, CLI's job
teardown	D/E	deletes tables and user data — must never be a browser action
deploy	D/E	CloudFormation stack + pkg/runtimeiam IAM policy

Package tiers

A — at parity, verified line-by-line:

• matcher.go Evaluate → src/core/matcher.ts — both branches, both rejection paths, the candidateAzs carry, the "spot watch with no price = no match" fallthrough
• azAllowed / orderAZs → src/core/azs.ts — including "empty az is always allowed" and pin-order-wins
• wildcardToRegex → src/core/pattern.ts — same metachar set ^$()[]{}+\, same escape order
• ParseDuration → src/core/duration.ts (ms instead of ns, documented)
• searchBestMatch → CapacityWatcher.check — same cheapest-wins fold

B — portable, missing → filed:

• Port the launch-failure classifier (pkg/failure) — the retry taxonomy is the tool's core judgement #2 pkg/failure (148 lines) — the capacity/terminal/unknown retry taxonomy. Highest-value pure port available.
• Port the small pure helpers: schedule expressions, service/pattern validation, webhook URL vetting #3 schedule_expr.go, service.go, validation.go
• Watch persistence: DynamoDB is browser-reachable, so list/status/cancel/extend/history are portable #4 store.go read/update half (759 lines total; the provisioning half is D)

C/D — needs a daemon or a node:

• poller.go (722) — the sweep: filters, leases, recordOutcome state machine, PollSummary. The per-watch matching is ported; the multi-watch supervisor loop is a daemon.
• spawner.go (383) — calls spawn to launch; AZ-retry within a cycle. Belongs to spawn-ts's launch path, not here.
• holder.go (84) — CreateCapacityReservation ODCR hold. Actually browser-reachable (EC2 is CORS-open) but it creates a billable reservation, so it needs the same human-in-the-loop treatment as RunInstances; classify as B-with-a-guard rather than a free port.
• notifier.go (224) — SNS + webhook POST with the dial-time SSRF guard, which a browser cannot reproduce (see Port the small pure helpers: schedule expressions, service/pattern validation, webhook URL vetting #3).
• snipe.go (255) — the stateless block-and-wait acquire. Interesting for a browser once Port the launch-failure classifier (pkg/failure) — the retry taxonomy is the tool's core judgement #2 lands, since it needs no store; blocked on launch capability.
• scheduled.go (207) — scheduled-launch records + IfExists overlap policy (skip default for one-shots so an --at into a Capacity Block can't double-launch).
• lambda/capacity-poller (320), pkg/deploy (283), pkg/runtimeiam (144), pkg/awscfg (65 — no ~/.aws in a browser), pkg/testutil (114).

E — deliberately excluded: sagemaker.go (155) + the --service sagemaker surface. Symmetric to truffle-ts's SageMaker exclusion; ValidateWatchPattern's ml.* guard is still worth porting (#3).

Also missing from the domain model

src/core/types.ts documents itself as a trimmed subset, which is fair, but two omissions have behavioural weight:

• WatchStatus lacks completed — Go added it for goal-driven fleet watches (--until became true), and it's distinct from matched (a single-shot that fired once). Collapsing them loses the difference between "the work is done" and "we launched something".
• DesiredCount / CompletionCondition — the fleet-supervisor fields. conditions.ts already ports the --until parser, so lagotto-ts can evaluate a completion condition it has no field to store. Either carry the fields or say in the type doc that fleet watches are out of scope.

Priority

#1 (silent single-region watch) → #2 (failure classifier) → #4 read-only half → #3. #1 is blocked on truffle-ts#31.