golem-add-ignite-scala

name	golem-add-ignite-scala
description	Using Apache Ignite from a Scala Golem agent through golem.host.Rdbms.Ignite. Use when the user asks to connect to Apache Ignite 2, run SQL over Ignite, or use Ignite from Scala agent code.

Using Apache Ignite from a Scala Agent

The Scala SDK already wraps golem:rdbms/ignite2@1.5.0 in golem.host.Rdbms.

Imports

import golem.host.Rdbms
import golem.host.Rdbms._

Open a Connection

Ignite uses thin-client URLs like ignite://host:10800.

Rdbms.Ignite.open("ignite://127.0.0.1:10800")

open, query, execute, commit, and rollback all return Either[DbError, T] instead of throwing.

If the user asks for a method that returns a plain String, keep the public method signature as String and handle host errors inside the method (e.g. with .fold(e => throw new RuntimeException(e.toString), identity)) rather than changing the signature to Either[DbError, _].

Query Data

Ignite placeholders use ?.

val message =
  for {
    conn   <- Rdbms.Ignite.open("ignite://127.0.0.1:10800")
    result <- conn.query("SELECT ?", List(IgniteDbValue.DbString("hello")))
    row    <- result.rows.headOption.toRight(DbError.Other("query returned no rows"))
    value  <- row.values.headOption.toRight(DbError.Other("query returned no columns"))
    text   <- value match {
                case IgniteDbValue.DbString(value) => Right(value)
                case other                         => Left(DbError.Other(s"Unexpected Ignite value: $other"))
              }
  } yield text

Execute Statements

conn.execute(
  """CREATE TABLE IF NOT EXISTS notes (
    |    id INT PRIMARY KEY,
    |    body VARCHAR
    |) WITH "CACHE_NAME=notes"""".stripMargin,
  List.empty,
)

When creating Ignite tables through SQL, include WITH "CACHE_NAME=...".

Transactions

for {
  conn <- Rdbms.Ignite.open(url)
  tx   <- conn.beginTransaction()
  _    <- tx.execute(
            "INSERT INTO notes (id, body) VALUES (?, ?)",
            List(IgniteDbValue.DbInt(1), IgniteDbValue.DbString("hello")),
          )
  _    <- tx.commit()
} yield ()

If you need transactional tables, create them with ATOMICITY=TRANSACTIONAL in the table options.