db provider

The db provider projects one SQLite database into a read-only filesystem. It is useful for schema inspection and bounded samples, not arbitrary SQL execution.

Read-only prevents writes, not disclosure. sample.json can expose table data. Mount only databases that are safe for local processes with access to /omnifs/db to inspect.

At a glance

Field	Value
Provider id	db
Default mount	/db
WASM	omnifs_provider_db.wasm
Manifest	providers/db/omnifs.provider.json
Routes	providers/db/src/lib.rs
Auth	none
Capabilities	read-only WASI preopen for the selected database file’s parent directory; declared memory need 128 MB

Setup

omnifs init db
omnifs up
omnifs shell

omnifs init db asks for the SQLite file. The selected file’s parent directory is preopened read-only as /data, and the provider opens the configured guest-visible path inside it. No upstream credentials are involved.

Main paths

/db/meta
/db/meta/info.json
/db/tables
/db/tables/{table}
/db/tables/{table}/table.json
/db/tables/{table}/schema.sql
/db/tables/{table}/schema.json
/db/tables/{table}/indexes.json
/db/tables/{table}/count.txt
/db/tables/{table}/sample.json

Examples

ls /omnifs/db/tables
cat /omnifs/db/meta/info.json | jq .
cat /omnifs/db/tables/Album/table.json | jq .
cat /omnifs/db/tables/Album/schema.sql
cat /omnifs/db/tables/Album/schema.json | jq .
cat /omnifs/db/tables/Album/count.txt
cat /omnifs/db/tables/Album/sample.json | jq .

Configuration

Key	Required	Default	Meaning
database_type	yes	sqlite	Database backend. Supported value: sqlite.
path	yes	/data/test.db	SQLite database path.
read_only	no	true	Open the database read-only.
sample_limit	no	20	Maximum rows returned in sample.json.

The mount remains a read projection. Setting read_only is about how SQLite opens the file internally; it does not turn omnifs into a writable database mount.

Cache behavior

/meta and /tables/{table} are object routes with canonical JSON bytes and rendered leaves. sample.json is a separate projection because row samples are bounded reads over table data.

Limitations

The db provider supports SQLite. It does not execute arbitrary SQL from the mounted filesystem. Table names are limited to tables known when the provider starts.