Serializes Mailglass.Tenancy.current/0 across Oban job boundaries (D-33).

Enqueue side

Phase 3 Mailglass.Outbound adds a put_tenant_in_args/2 helper that merges %{"mailglass_tenant_id" => current()} into job args at enqueue time. The serialized value is a plain string — JSON-safe, no coercion.

Perform side

Two equivalent integration paths — both converge on Mailglass.Tenancy.with_tenant/2.

OSS Oban (wrap_perform/2)

OSS Oban 2.21 has no middleware behaviour. Adopters wrap their worker's perform/1 body:

defmodule MyApp.MailerWorker do
  use Oban.Worker

  @impl Oban.Worker
  def perform(job) do
    Mailglass.Oban.TenancyMiddleware.wrap_perform(job, fn ->
      # ... worker body; Mailglass.Tenancy.current/0 now returns
      # the tenant stamped at enqueue time.
      :ok
    end)
  end
end

Oban Pro (call/2)

Oban Pro's Oban.Middleware behaviour invokes call/2. The shape this module exports matches the documented behaviour (job + next/1 continuation) so Pro adopters register it directly:

config :my_app, Oban,
  engine: Oban.Engines.Basic,
  middleware: [Mailglass.Oban.TenancyMiddleware],
  queues: [mailglass: 10]

Contract

• job.args["mailglass_tenant_id"] present and binary → wrap in Mailglass.Tenancy.with_tenant/2.
• Key missing or non-binary → pass through unchanged. Lets adopters phase in the middleware without breaking existing jobs.
• If the wrapped body raises, the prior tenant stamp is restored before the raise propagates (inherited from Mailglass.Tenancy.with_tenant/2).