Configure the database connection#

Tell the application where its Postgres is, size the pool, and keep several applications apart in one database.

The defaults#

With nothing set, eezo connects to jdbc:postgresql://localhost:5442/eezo as postgres with password postgres. This Docker command starts exactly that:

docker run -d --name eezo-pg -p 5442:5432 \
  -e POSTGRES_PASSWORD=postgres -e POSTGRES_DB=eezo postgres:17

Port 5442 rather than 5432 so it doesn't collide with a Postgres you may already have.

Pointing it elsewhere#

Two ways, and the first one wins when both are set:

EEZO_DB_URL, EEZO_DB_USER, EEZO_DB_PASS: a JDBC URL and the credentials, separately.
DATABASE_URL in the postgres://user:password@host/db form that Fly, Heroku and Render inject. eezo parses it into the three values above.

EEZO_DB_URL=jdbc:postgresql://db.internal:5432/bookshelf EEZO_DB_USER=app EEZO_DB_PASS=... eezo dev

TLS#

A DATABASE_URL is treated as a platform URL, and eezo requires TLS on it unless the URL says otherwise with its own sslmode. Fly's postgres attach writes sslmode=disable on purpose, since its traffic stays on a private network. A database elsewhere that only speaks clear text needs sslmode=disable appended to the URL, or a raw JDBC URL in EEZO_DB_URL, which is taken as written.

The pool#

EEZO_DB_POOL_SIZE: connections in the pool, default 10.
EEZO_DB_ACQUIRE_TIMEOUT: milliseconds a request waits for a connection before it fails, default 5000. A request that waits longer answers 500.

The pool starts empty and grows to the size as connections are needed.

One database, several applications#

Each application can keep its tables in a Postgres schema of its own, so two applications can share the dev database without their drift bleeding into each other. Two overrides on Main, told once each:

import java.sql.Connection

object Main extends EezoApp {

  override def databaseSchema: String = "bookshelf"

  override def databaseInit: Connection => Unit = { c =>
    val st = c.createStatement()
    try {
      st.execute("""create schema if not exists "bookshelf"""")
      st.execute("""set search_path to "bookshelf"""")
    } finally st.close()
  }
  // ...
}

databaseInit runs on every pooled connection, because search_path is per connection. databaseSchema points the schema commands' catalog reads at the same name, so status compares your model against the right tables. Both halves are needed; the examples under examples/ each do this.

In tests#

Point a second DbApp at a throwaway Postgres, such as one from testcontainers, by overriding databaseUrl, databaseUser and databasePassword. Test an application shows the shape.