"No async task available" on rake db:migrate

[mpugach]

Added async-postgres and got "No async task available" on rake db:migrate

Same error when trying to execute any ActiveRecord statement in Rails console

[hopsoft]

This also happens when eager loading classes and attempting to run the Rails console.

It's because Task.current is nil when the Postgres::Proxy constructor is invoked.

#lib/async/postgres/pool.rb
module Postgres
  class Proxy
    def initialize(connection_string, task: Task.current)
      @connection_string = connection_string 
      pools = task.reactor.postgres_pools \|\|= {} # <- FAILS
      ...

I dug into this a little but it's not obvious how to setup the reactor and create the current task so Rails initialization works correctly.

[ioquatix]

I've been thinking about this.

It's probably best to require async-postgres only in the server context, i.e. config.ru.