Flowcesinha - utility libraries for Cloudflare Workflows

Flowcesinha (pronunced ˈfloʊsɨˈziɲɐ - paste it here to hear it) is a batteries included and zero-dependencies library that empowers developers with powerful abstractions for Cloudflare Workflows.

> [!WARNING]
> Flowcesinha is in a beta state, so use with care. Type breakages might (and probably will) happen.

Some notable features:

- Custom storage engines and lazy step results (R2 included) so that, you can store more state inside of an step (and you can bring your own storage engine!);
- Error reporting (Sentry provided in flowcesinha-sentry) and Workflow failure handler;
- Reversable steps: ability to add a revert callback in case that the workflow fails;
- Durable fetch: ability to fetch from APIs with dynamic retries (that come from the Retry-After header);
- Functional primitives: doMap (map but every call is done inside of a step);
- ... more to come soon!

See it in action

Assume we are a travelling-agency and we want to make a Workflow that books a plane and a hotel:

``ts
type Env = {
// Add your bindings here, e.g. Workers KV, D1, Workers AI, etc.
MY_WORKFLOW: Workflow;
R2_BUCKET: R2Bucket;
};
export class MyWorkflow extends WorkflowEntrypoint {
async run(event: WorkflowEvent, step: WorkflowStep) {
return useFlowcesinha(
{
ctx: this.ctx,
env: this.env,
event,
step,
workflowName: this.constructor.name, // equivalent to writing "MyWorkflow"
options: {
storageEngine: new R2Storage(this.env.R2_BUCKET),
errorReporter: new SentryErrorReporting({
context: this.ctx,
dsn: 'YOUR-SENTRY-DSN',
}),
globalFailureHandler: (error) => {
console.log('Workflow failed!', error);
},
},
},
async (event, step) => {
// Because we are using a storage engine, everything that is a step is stored in it, which means that
// we can store more than 1MiB of state per step
const providersResp = await step.fetch("Get providers for flight", "https://flight-searcher/providers");

const providers = await providersResp.json();

const cheapestFlight = await step.do("Choose cheapest flight", async () => {
// assume that you have calculated the cheapest flight here
return "LIS-LAX";
});

await step.reversableDo("Book flight", async () => {
// assume that we have done some API call to the provider to reserve the flight
return await cheapestFlight.getFull()
}, async () => {
// if the workflow fails after this step, it will run this callback so that, you can cancel the flight booking
});

await step.reversableDo("Book hotel", async () => {
// assume that we have done some API call to the provider to reserve the hotel
return "Hilton"
}, async () => {
// if the workflow fails after this step, it will run this callback so that, you can cancel the hotel booking
});

return 'finished';
},
);
}
}
`

Why is it called Flowcesinha?

Simply put, it's just derived from Workflow + Francesinha = Flowcesinha`.

A Francesinha is a Portuguese sandwich, originally from Porto, that consists of many layers of all kinds of meats with melted cheese on top and most importantly a tomato-and-beer sauce (not with the sweet-like sauce, those don't count as real Francesinhas). These packages thrive to do the same, bring many good components together for a beautiful ~~gastronomic experience~~ developer experience.