Rails Jobs

Rails Jobs

Use for background job design and review. Patterns from Campfire (Resque, 4 thin jobs) and Fizzy (Solid Queue, multi-queue).

Defaults

• Keep jobs shallow; the job body is one line calling a model method: def perform(card) = card.notify_recipients.
• Make jobs idempotent and safe to retry (e.g. rescue RecordNotUnique in the domain op).
• Fail loudly on real errors; avoid silent rescue patterns.
• Set ActiveJob::Base.enqueue_after_transaction_commit = true in app defaults — fixes job-before-data races at the root.
• Prefer Solid Queue (database-backed) over Redis-backed queues for new apps; co-locate with Puma (SOLID_QUEUE_IN_PUMA) in small deployments.

Naming Convention

• _later enqueues, plain name does the work, _now when you need an explicit synchronous twin:

def notify_recipients          # the work — public API the job calls
def notify_recipients_later   # enqueues NotifyRecipientsJob (often private, called from callbacks)

• Capture enqueue-time context as keyword args (Mention::CreateJob.perform_later(self, mentioner: Current.user)) — don't rely on Current at perform time.
• In multi-tenant apps, serialize tenant context into every job: prepend an ApplicationJob extension that captures Current.account at enqueue (as a GlobalID) and wraps perform_now in Current.with_account.

Good Patterns

• Small job payloads; pass records (GlobalID) or IDs, never big object graphs.
• Queues split by criticality (default, backend, webhooks) with explicit priority order in queue config.
• Separate orchestration jobs from heavy processing jobs.
• Stagger recurring jobs at odd minutes (12, 27, 50) to avoid synchronized load spikes.
• Bulk enqueue: due.in_batches { |batch| ActiveJob.perform_all_later(batch.map { DeliverJob.new(it) }) }.
• Crash-safe long iteration with ActiveJob::Continuable: step :dispatch + find_each(start: step.cursor) + step.advance! — essential for fan-out (webhooks, broadcasts, backfills).
• Serialize per-owner work with limits_concurrency to: 1, key: ->(owner) { owner } (Solid Queue).
• Two-tier async for high fan-out HTTP (web push): one job for the domain event, then an in-process thread pool for the HTTP calls. Resolve all AR data before posting to the pool; drop on RejectedExecutionError for backpressure.
• For after_destroy_commit async work, snapshot needed associations in before_destroy — the parent rows may be gone when the job runs.

Recurring & Maintenance

• Recurring tasks invoke plain model class methods (command: "MagicLink.cleanup"), not dedicated job classes.
• Retention sweeps use delete_all on scopes (stale.delete_all) — skip callbacks on stale rows.
• Schedule cleanup for finished queue jobs, expired tokens, old delivery records.
• Prefer reset-on-use over cron resets: check-and-reset inside the domain method (spend calls reset_if_due), not a scheduled job.
• Trim recurring schedules in beta/staging environments to essentials.

Error Handling Policy

• Retry transient failures with retry_on ..., wait: :polynomially_longer (timeouts, DNS, Net::SMTPServerBusy).
• Don't retry permanent failures: rescue, classify by error class/message, log at :info severity (it's expected — bad address, full mailbox), and move on. Keep job queue resources for work that can succeed.
• Distinguish "destination failed" (record outcome, complete the job) from "our code raised" (mark errored, re-raise for retry) — see rails-webhooks.
• Package error taxonomies as concerns and include them into framework jobs (ActionMailer::MailDeliveryJob.include SmtpDeliveryErrorHandling).

Testing

• Don't unit-test trivial job classes; test async behavior from model tests with perform_enqueued_jobs(only: Mention::CreateJob) { ... } and assert_enqueued_with(job: ...).
• Assert the observable outcome (mention created, email sent), not job internals.

Red Flags

• Jobs with complex branching and business rules embedded directly.
• Non-idempotent side effects without guards.
• Retrying permanently invalid inputs.
• Enqueueing jobs before required records are committed.
• Reading Current.user/Current.account inside perform without serializing it at enqueue.
• Per-item perform_later in a loop where perform_all_later or Continuable iteration fits.
• Cron-style reset jobs when reset-on-use logic is simpler and safer.
• Background jobs triggering spurious Turbo broadcasts (wrap in suppressing_turbo_broadcasts).