resonate-external-system-of-record-pattern-rust

What problem does it solve?

Prevents durable workflows from producing inconsistent business state by ensuring Resonate coordinates but does not contradict an external system of record (SoR); it enforces writing to the SoR first and making dependent side effects checkpointed and idempotent so retries do not create duplicate or conflicting outcomes.

Core Features & Use Cases

• SoR-first writes: Patterns and idioms for performing idempotent inserts/updates to PostgreSQL or ledger systems before triggering side effects.
• Type-dispatched dependency injection: Guidance for registering dependencies in the ephemeral world and retrieving them as Arc<T> inside durable functions.
• Idempotency and deduplication: Use of deterministic invocation IDs, idempotency keys, ON CONFLICT SQL patterns, and ledger transfer IDs to ensure at-most-once external effects.
• Use Case: Implement reliable order creation and payment charging where the database or ledger is the ground truth and external APIs (Stripe, fulfillment) are invoked only after durable SoR commits.

Quick Start

Ask for a Rust Resonate example that registers a PgPool and Stripe client as dependencies, inserts an idempotent order row into Postgres as the system of record, and then enqueues dependent side effects.