class CQL::Postgres::EngineSource

• CQL::Postgres::EngineSource
• CQL::ConnectionSource
• Reference
• Object

Overview

Runs a CQL::Schema on an AsyncEngine's pool: models, queries, migrations, schema.transaction and schema.with_connection use the engine's fiber-safe pool, statement cache and health checks without using(engine).

SOURCE = CQL::Postgres::EngineSource.connect("postgres://app@db/app?pool_size=10")

AppDB = CQL::Schema.define(:app, "postgres://app@db/app", CQL::Adapter::Postgres, source: SOURCE) do
  table :users do
    primary :id, Int64, auto_increment: true
    text :name
  end
end

SOURCE.engine.pipeline([AppDB.query.from(:users).select(:name)]) # the engine's own API stays reachable

A connection that cannot be opened raises DB::ConnectionRefused and a saturated pool DB::PoolTimeout (the engine itself raises the underlying IO::Error and CQL::Postgres::PoolTimeout, kept as cause). crystal-db's pool raises DB::ConnectionRefused only for the first connect and DB::PoolRetryAttemptsExceeded for a lazy one, so code rescuing that class will not match here. A closed pool raises CQL::Postgres::PoolClosed. The engine does not retry connects. Closing the source closes the engine for every schema that shares it.

Defined in:

Constructors

• .connect(url : String, adapter : CQL::Adapter | Nil = nil, setup : Proc(Connection, Nil) | Nil = nil, reset : String | Nil = nil) : EngineSource
• .new(engine : AsyncEngine)

Instance Method Summary

• #adapter : CQL::Adapter | Nil

  The adapter this source speaks, when it is bound to one (a Schema refuses a different one).

• #close : Nil
• #database_uri(uri : String) : String

  The URL without the engine's pool options (pool_size, max_queries, ...), for code that opens a second connection from Schema#uri through crystal-db (SchemaDump).

• #engine : AsyncEngine
• #pool_stats : PoolStats
• #transaction(& : DB::Transaction -> _)

  Runs the block in a transaction on one connection: committed when the block returns, rolled back when it raises.

• #using_connection(& : DB::Connection -> _)

  Lends one connection to the block and takes it back afterwards.

Constructor Detail

Instance Method Detail