Installation

Toolchain

Corium builds with a stable Rust toolchain, version 1.85 or newer. It uses edition 2024.

Build the CLI:

cargo build -p corium-cli --release

The binary is target/release/corium. Copy it to a directory on the path of the operator, for example /usr/local/bin/corium.

Run the test suite before you promote a build:

cargo test --workspace

Cargo features

Optional backends and authentication methods are Cargo features of corium-cli. A feature that is not compiled in makes its flags fail at startup with a clear error.

Feature	Default	Enables
cljrs	Yes	The :db/fn Clojure transaction-function runtime.
postgres	No	--store postgres.
turso	No	--store turso.
s3	No	--store s3.
oidc	No	OIDC bearer tokens with a JWKS file.
oidc-discovery	No	OIDC, and JWKS fetch from the issuer.

Build a production binary with the backends that you deploy:

cargo build -p corium-cli --release --features postgres,s3,oidc-discovery

A backend can also be loaded at run time instead of compiled in. Build the driver crate on its own, and give the transactor its library path:

cargo build -p corium-store-turso --release

Do not enable the static-link feature when you build a loadable library. That feature is for a host that links the driver in. See storage plugins.

Workspace build note

corium-cljrs and the MusicBrainz example are excluded from the default workspace members. A --workspace build unifies the Clojure runtime into no-gc mode and degrades their garbage-collection semantics.

Build and test those two crates on their own:

cargo test -p corium-cljrs
cargo test -p corium-mbrainz

What a deployment needs

A minimal deployment has one transactor process and one storage backend.

Add a peer server only when a client language has no peer library. Add a PostgreSQL wire server only when a SQL client must reach the data.

Process	Default port
corium transactor	4334
corium peer-server	4336
corium postgres-server	5432
Metrics endpoint	None. Set --metrics-listen.

Directory layout of the fs store

The filesystem store keeps two directories under --data-dir.

Path	Content
<data-dir>/store	Blobs and root records.
<data-dir>/logs	Versioned transaction log files.

Back up the data directory as a unit, or use corium backup. Do not edit files in either directory by hand.

Process supervision

Run the transactor under a supervisor, such as systemd. Two rules apply.

• Give the transactor a stable --owner value. A restarted member re-acquires its own unexpired lease at once.
• Stop the transactor with SIGINT, which Ctrl-C sends. The transactor releases its leases on the way out. A standby then takes over without waiting for the lease to expire.

Partly implemented. The transactor and the peer server listen for SIGINT only. SIGTERM kills the process, which leaves the lease held until it expires. A shutdown by SIGTERM is safe, because takeover is ordinary crash recovery, but failover then costs one full lease time-to-live.

For systemd, set the stop signal explicitly:

[Service]
ExecStart=/usr/local/bin/corium transactor --config /etc/corium/transactor.edn
KillSignal=SIGINT
Restart=on-failure