Open_Ultra_SAST/docs/rustfs.md

RustFS setup for the memory store

The plane's memory store can live in an S3-compatible bucket: OUSAST_MEMORY=s3://sast-memory selects S3Store (src/openultrasast/plane/memory.py), which talks to the server through boto3. Any S3-compatible store with bucket versioning, lifecycle rules, object tags and S3 Select works; RustFS is the server the contract tests run against. The maintainer's server is RustFS at files.because-security.com, bucket sast-memory, store at the bucket root. What the store keeps there is described on Memory.

The store never configures its bucket. An admin sets the bucket up once with admin credentials. The agent account the store runs as can read the bucket's settings but not change them, and reads and writes objects freely. Every time the store opens, it checks the setup and refuses to start if anything is missing.

flowchart LR
    admin["Admin, once: versioning on, runs/ expiry rule"] --> bucket[("Bucket sast-memory")]
    agent["Agent account: read settings, read and write objects and tags"] --> verify{"verify_bucket at startup"}
    bucket --> verify
    verify -- "all present" --> store["S3Store serves reads and writes"]
    verify -- "anything missing" --> refuse["MemoryStoreError naming each missing piece and its admin command"]

One-time admin steps

Run these with admin credentials (not the agent's). Both use the AWS CLI against the RustFS endpoint.

1. Turn versioning on. Provenance cites object version ids.

aws s3api put-bucket-versioning \
    --endpoint-url https://files.because-security.com \
    --bucket sast-memory \
    --versioning-configuration Status=Enabled

2. Expire raw run outputs under runs/ after 30 days. Everything else (repos/, facts/, index.jsonl and the blobs) is kept, so the rule must be a plain prefix filter on runs/.

aws s3api put-bucket-lifecycle-configuration \
    --endpoint-url https://files.because-security.com \
    --bucket sast-memory \
    --lifecycle-configuration '{"Rules":[{"ID":"ousast-runs-expiry","Status":"Enabled","Filter":{"Prefix":"runs/"},"Expiration":{"Days":30}}]}'

put-bucket-lifecycle-configuration replaces every rule on the bucket. If the bucket already has rules, merge this one into them first. The rule id ousast-runs-expiry and the 30 days are the store's defaults (RUNS_RULE_ID, RUNS_EXPIRE_DAYS); the store accepts any enabled, untagged prefix rule on runs/ with a number of days.

To read the result back:

aws s3api get-bucket-versioning --endpoint-url https://files.because-security.com --bucket sast-memory
aws s3api get-bucket-lifecycle-configuration --endpoint-url https://files.because-security.com --bucket sast-memory

The agent policy

Attach this policy to the agent account (the account whose keys go into .env). It is the complete policy: nothing else is needed, and it grants no Put* on versioning or lifecycle.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "BucketSettingsReadOnly",
      "Effect": "Allow",
      "Action": [
        "s3:ListBucket",
        "s3:ListBucketVersions",
        "s3:GetBucketLocation",
        "s3:GetBucketVersioning",
        "s3:GetLifecycleConfiguration"
      ],
      "Resource": ["arn:aws:s3:::sast-memory"]
    },
    {
      "Sid": "ObjectsReadWrite",
      "Effect": "Allow",
      "Action": [
        "s3:GetObject",
        "s3:GetObjectVersion",
        "s3:PutObject",
        "s3:DeleteObject",
        "s3:DeleteObjectVersion",
        "s3:GetObjectTagging",
        "s3:PutObjectTagging",
        "s3:GetObjectVersionTagging"
      ],
      "Resource": ["arn:aws:s3:::sast-memory/*"]
    }
  ]
}

Statement	Resource	In one line
BucketSettingsReadOnly	arn:aws:s3:::sast-memory	The agent can list the bucket and its versions and read its location, versioning and lifecycle settings, which is what the startup check needs; it cannot change them.
ObjectsReadWrite	arn:aws:s3:::sast-memory/*	The agent reads, writes and deletes objects and their versions and reads and writes object tags; this covers row objects, blobs, the index, the Select probe, and the kind tag the store filters by.

So the agent writes objects freely but cannot change bucket settings: turning versioning off or removing the expiry rule needs the admin.

The .env settings

The store reads its endpoint and credentials from .env in the working directory or from the environment (s3_settings), never from a manifest, and never prints them. The names are the ones the AWS SDKs and CLI use for credentials, so one .env serves both the store and aws s3api.

Variable	Value for this server	Notes
OUSAST_MEMORY	s3://sast-memory	s3://<bucket>[/<prefix>]; s3:// alone uses S3_BUCKET; unset means the local FileStore
S3_ENDPOINT	https://files.because-security.com	the full URL, scheme included (https://host[:port]); required
AWS_ACCESS_KEY_ID	the agent account's access key	required
AWS_SECRET_ACCESS_KEY	the agent account's secret key	required
AWS_SESSION_TOKEN	optional	for temporary credentials
S3_REGION	optional (us-east-1 when unset)	the SigV4 signing region; spares a GetBucketLocation call
S3_BUCKET	sast-memory	the bucket s3:// names when the URL has none; also the real-server tests' default bucket

The client signs with SigV4 and uses path-style addressing (https://host/bucket/key), which RustFS needs. The SDK's own checksum trailers are off, because not every S3-compatible server accepts them.

• Never commit .env. It is gitignored (.gitignore: .env, .env.*, except .env.example). .env.example lists these names with empty values.
• .env never overrides a variable already exported in your shell (config.load_dotenv). A stale export AWS_SECRET_ACCESS_KEY=... in your profile silently wins over the file; unset it when a change in .env seems to have no effect.
• The store needs the s3 extra (uv sync --extra s3, which installs boto3); without it opening the store fails with OUSAST_MEMORY=s3://... needs boto3: install openultrasast[s3]. A missing variable fails with OUSAST_MEMORY=s3://... needs S3_ENDPOINT, AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY in .env or the environment (naming only the missing ones); an endpoint without a scheme fails with S3_ENDPOINT must be a URL with a scheme (https://host[:port]).

What the store verifies at startup

S3Store.verify_bucket() runs once per process for each bucket and prefix. It reads the versioning status and the lifecycle rules, writes a two-line probe object at _probe/select.jsonl (under the prefix, if any), queries it with S3 Select and reads its tags. Every missing piece is collected into one error:

memory s3://sast-memory: the bucket is not set up for the store. The store never configures its bucket (an admin sets it once, the store verifies); missing:
  - <one line per missing piece>

The lines, exactly as the code writes them for this bucket at the root (<failure> is the server's error code and the first 200 characters of its message):

Check	Refusal line
versioning unreadable	versioning cannot be read (<failure>): the agent needs s3:GetBucketVersioning on arn:aws:s3:::sast-memory, and versioning must be Enabled
versioning off	versioning is Off, it must be Enabled (provenance cites object versions). Admin: aws s3api put-bucket-versioning --endpoint-url "$S3_ENDPOINT" --bucket sast-memory --versioning-configuration Status=Enabled (the actual status, e.g. Suspended, replaces Off when set)
lifecycle unreadable	the lifecycle configuration cannot be read (<failure>): the agent needs s3:GetLifecycleConfiguration on arn:aws:s3:::sast-memory, and a rule must expire runs/
a rule expires everything	lifecycle rule(s) <rule ids> expire the whole store (repos/, facts/ and the index would be deleted); limit them to runs/
no runs/ rule	no enabled lifecycle rule expires runs/ after a number of days. Admin (merged with any rules the bucket already has): aws s3api put-bucket-lifecycle-configuration --endpoint-url "$S3_ENDPOINT" --bucket sast-memory --lifecycle-configuration '{"Rules":[{"ID":"ousast-runs-expiry","Status":"Enabled","Filter":{"Prefix":"runs/"},"Expiration":{"Days":30}}]}'
tags unreadable	object tags cannot be read on _probe/select.jsonl (<failure>): the store filters row objects by their kind tag, so the agent needs s3:GetObjectTagging on arn:aws:s3:::sast-memory/*
S3 Select missing	S3 Select (SelectObjectContent over JSON Lines) does not answer on _probe/select.jsonl (<failure>). The store requires it and has no local fallback: use a server with S3 Select (RustFS has it; not every S3-compatible server does) and let the agent s3:PutObject and s3:GetObject

The admin commands inside the messages use --endpoint-url "$S3_ENDPOINT", which is the full URL from .env, so they run as written once .env is exported.

There is no fallback: the store does not start in a degraded mode, does not drop to a local store, and does not fetch and filter objects itself.

The RustFS Select limit and the fixed-schema rule

RustFS's S3 Select infers an object's JSON schema from its leading rows. A where field that is absent from those rows is unbound, even if a later row has it: the query fails with EvaluatorBindingDoesNotExist instead of matching (measured 2026-10-02 with the field first present at row 5000). The store does not read that as "no rows", since that answer could silently drop matches; it raises:

memory s3://sast-memory: S3 Select on <key> failed (EvaluatorBindingDoesNotExist: ...) (a field of [<fields>] is absent from the object's leading rows, which the server reads as its schema); the store has no local fallback

The rule that follows: a field the store filters on must be present in every row of its kind from the first row on, i.e. each row kind has a fixed set of queryable fields. Enforcing that set per kind in the store is in progress and not on main as of this page (see Memory).

Checks against the real server

The contract tests that talk to a real server run only with OUSAST_MEMORY_TEST_S3=1 (bucket OUSAST_MEMORY_TEST_BUCKET, else S3_BUCKET). They verify the bucket at its root, write only under a fresh contract-<id>/ prefix, and remove every version and delete marker under it afterwards; they never configure the bucket. More on the host setup: ax on this host.