cmd/seed: synthetic dataset for local development

[ZukwiZ]

Summary

Add a deterministic ~6-month synthetic dataset (~9.8k rows, gentle sinusoid with occasional spikes and quiet days) for exercising the dashboard locally without needing a real production export. The generator deliberately spans every period the chart picker offers (7d / 30d / 3m / 6m / 1y), so any range renders meaningful data.

Safety properties

• Refuses to run unless `Config.Environment == "development"`.
• `INSERT … ON CONFLICT (id) DO NOTHING`, so re-running is a no-op.
• Steam IDs use a clearly-synthetic `76561198000000000` prefix; real Steam IDs sit higher up the 64-bit range, so generated rows are easy to spot in the DB.
• Snowflake IDs encode the same `created_at` + sequence layout as the production generator (`domain/models/snowflake.go`), so synthetic rows sort chronologically alongside any real rows already present.

.gitignore

Adds `internal-docs/` (author scratch space) and `internal/devseed/fixtures/` (room for any future local-only CSV fixtures) so neither leaks into the public repo.

Test plan

• `go build ./cmd/seed`
• Against a local dev DB with `Environment=development`: `go run ./cmd/seed` prints `generated …` and `seed complete: N inserted, 0 already present`.
• Re-run: prints `seed complete: 0 inserted, N already present` (idempotent).
• With `Environment` set to anything else: exits non-zero with a refusal message.
• After seeding, the dashboard at `/` shows ~6 months of activity across all period picker ranges.

Made with Cursor

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Note

Low Risk
Dev-only CLI with an environment guard and idempotent inserts; not linked to the production server binary.

Overview
Adds a dev-only seed path so local Postgres can hold a deterministic ~6-month reversal history (~9.8k rows) without production exports.

go run ./cmd/seed loads config, exits unless Environment is development, then bulk-inserts generated rows into the public DB via ON CONFLICT (id) DO NOTHING (safe to re-run). internal/devseed builds daily volume with variance, marketplace mix, sources, optional expungements, synthetic Steam IDs, and snowflake IDs aligned with production ordering.

README documents the workflow and dashboard period coverage; .gitignore excludes internal-docs/ and optional internal/devseed/fixtures/.

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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Seed not idempotent due to time-dependent snowflake IDs

Medium Severity

GenerateSynthetic receives time.Now().UTC(), and all generated snowflake IDs embed createdAt timestamps derived from that value. Since today shifts daily and the nowMs cap changes every millisecond, re-running the seed at a different time produces entirely different snowflake IDs. Because ON CONFLICT (id) DO NOTHING keys on these IDs, a second run on a different day inserts ~9.8k additional rows instead of being a no-op, contradicting the documented idempotency guarantee. Anchoring to a fixed reference time instead of time.Now() would make the output truly deterministic.

Additional Locations (2)

• internal/devseed/synthetic.go#L42-L43
• internal/devseed/synthetic.go#L117-L119

 

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