---
title: "mova-seaspider-store — Mova code model"
description: "Mova code model of tools/seaspider/src/store.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/tools/seaspider/src/store.rs.groupant/"
---
Elamur: [Mova](https://md.mova.elamur.ai/free/en/) · [Dictionary](https://md.dictionary.elamur.ai/free/en/) · [Research](https://md.research.elamur.ai/free/en/) · **Groupants**

This page as HTML: <https://groupants.elamur.ai/free/en/mova/tools/seaspider/src/store.rs.groupant/>

# mova-seaspider-store

The groupant beside tools/seaspider/src/store.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.

## Facts

- **kind:** groupant
- **status:** partial source bound model
- **source:** [`tools/seaspider/src/store.rs`](https://github.com/ElamurAI/mova-free/blob/main/tools/seaspider/src/store.rs)
- **source SHA-256:** `b8a8bfcdd5d8d33b…`
- **repository folder:** [`tools/seaspider/src/store.rs.groupant`](https://github.com/ElamurAI/mova-free/tree/main/tools/seaspider/src/store.rs.groupant)
- **repository commit:** `48f2e6f74146`

> **Implementation material.** A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.

## Components

| component | label | where |
|---|---|---|
| **approximant** | partial | [Forward approximant](#forward-approximant) |
| **ast** | partial | `syntax.json` |
| **composition** | partial | [Composition](#composition) |
| **cost** | partial | [Cost](#cost) |
| **descriptant** | present | [Descriptant](#descriptant) |
| **invariant** | partial | [Invariant](#invariant) |
| **tests** | finite evidence | [tests](#tests) |

## Obernants

The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.

| id | type | label | where |
|---|---|---|---|
| `behavior_complement` | behavior_complement | partial source derived model | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial source derived model | [reverse_reconstruction](#reverse-reconstruction) |

## Model text


### model

## mova-seaspider-store

### Descriptant

Compressed raw page store: zstd frames with checksums appended to rolling segments, an fsynced JSONL journal, links file, readers by URL or sha256, intent/uncertain bookkeeping. Source: `tools/seaspider/src/store.rs`.

### Forward approximant

open: create seg/, cut a torn journal tail, index complete lines (by URL incl. final URL, by sha256), continue the highest segment at its file length, append one 'uncertain' line per dangling intent. put_body: sha256; reuse an existing frame of the same hash; else compress with checksum, roll to a new segment once seg_len >= cap, append, fsync. append: line + newline, fsync. done(url): latest page record not 'error' and younger than refetch age. read_body: read frame, decompress with cap body_bytes+1, require sha256 match.

### Invariant

Every journal line with seg/off/len points at bytes fsynced before the line was written; a successful read returns bytes whose sha256 equals the record; a torn last line never becomes a record; a dangling intent produces exactly one uncertain line.

### Cost

open O(journal bytes); put_body O(body) compression plus one fsync; append one fsync; get O(frame) after the O(journal) index.

### Composition

crawl appends robots/intent/page records and links lines; main's get/stats use Reader.

### behavior_complement

Not provided: concurrent writers (no lock), deletion or compaction, per-domain dictionaries or deltas (Spider features not carried), encryption. Counterexample: a flipped byte inside a frame makes get fail instead of returning wrong bytes (corrupted_frame_detected). Evidence status: source-derived model with finite checks, not a proof.

### reverse_reconstruction

From a record and the segments the exact decoded body is recoverable and verified by sha256; the transfer encoding and bytes beyond max_body are not. From a sha256 alone any of the records sharing it is a compatible antecedent (bodies are deduplicated). No unique inverse is claimed.

### one_writer_lock

2026-11-04: the writer holds an exclusive lock on `lock` in the store directory for its lifetime; a second Sea Spider on the same store refuses to start, so one crawler writes a store at a time (the runtime is single-threaded and requests sequential). Negative control: without the lock the second-writer test fails.

### tests

#### Checks

Five unit tests: round trip with dedup and sha lookup, segment roll-over at the cap, torn tail with orphan bytes (negative control: torn line is no record), corrupt frame, dangling intent recorded once.

Command: cargo test --manifest-path tools/seaspider/Cargo.toml --offline --locked (27 unit + 9 end-to-end tests against a local 127.0.0.1 HTTP server; two identical runs on 2026-11-04).
These are finite fixtures; the only live run was the 2026-11-04 smoke against the project's own site.