Expand Up @@ -168,7 +168,7 @@ ignored. | ------------------ | ------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `--port` | `PORT` | The port on which the Functions Framework listens for requests. Default: `8080` | | `--target` | `FUNCTION_TARGET` | The name of the exported function to be invoked in response to requests. Default: `function` | | `--signature-type` | `FUNCTION_SIGNATURE_TYPE` | The signature used when writing your function. Controls unmarshalling rules and determines which arguments are used to invoke your function. Default: `http`; accepted values: `http` or `event` or `cloudevent` | | `--signature-type` | `FUNCTION_SIGNATURE_TYPE` | The signature used when writing your function. Controls unmarshalling rules and determines which arguments are used to invoke your function. Default: `http`; accepted values: `http` or `event` or `cloudevent` or `openfunction` | | `--source` | `FUNCTION_SOURCE` | The path to the directory of your function. Default: `cwd` (the current working directory) |
You can set command-line flags in your `package.json` via the `start` script. Expand Down Expand Up @@ -196,7 +196,52 @@ Dapr bindings allows you to trigger your applications or services with events co
Asynchronous function introduces Dapr pub/sub to provide a platform-agnostic API to send and receive messages. A typical use case is that you can leverage synchronous functions to receive an event in plain JSON or Cloud Events format, and then send the received event to a Dapr output binding or pub/sub component, most likely a message queue (e.g. Kafka, NATS Streaming, GCP PubSub, MQTT). Finally, the asynchronous function could be triggered from the message queue.
More details would be brought up to you in some quickstart samples, stay tuned. Async function use below function signature which is quite difference from that of Express style sync function:
```js function (ctx, data) {} ```
* `ctx`: OpenFunction [context](https://github.com/OpenFunction/functions-framework-nodejs/blob/master/src/openfunction/function_context.ts) object * `ctx.send(payload, output?)`: Send `payload` to all or one specific `output` of Dapr Output [Binding](https://docs.dapr.io/reference/components-reference/supported-bindings/) or Pub [Broker](https://docs.dapr.io/reference/components-reference/supported-pubsub/) * Notice that `ctx.send` CAN be invoked where necessary, when you have certain outgoing data to send * `data`: Data recieved from Dapr Input Binding or Sub Broker
For more details about async function and demo, please check out our [Node.js Async Function Quickstart](https://openfunction-talks.netlify.app/2022/202-node-async/).
#### HTTP Trigger Async Function
Sync functions is triggered by HTTP request, so Dapr is not used in sync function input. Whenever there are functions output requirements, sync functions can also send output to Dapr output binding or pubsub components.
Here is another function sample:
* Users send a HTTP request to a [Knative Sync function](https://github.com/OpenFunction/samples/tree/main/functions/knative/with-output-binding). * This sync function handles the request and then send its output to Kafka through a Dapr Kafka output binding or pubsub component. * An [async function](https://github.com/OpenFunction/samples/tree/main/functions/async/bindings/kafka-input) is then triggered by this output event in Kafka (through a Dapr Kafka input binding or pubsub component)
Node.js Functions Framework also supports such use case, you can switch Express function signature to typical async style as below example indicates:
```js async function tryKnativeAsync(ctx, data) { // Receive and handle data from HTTP request's body console.log('Function should receive request: %o', data);
// Send output in async way via Dapr await ctx.send(data);
// Use `ctx.res` object to deal with HTTP response ctx.res.send(data); ```
Remember that you also need set command-line flags `--signature-type=openfunction`, for example in your `package.json` via the `start` script:
```js "scripts": { "start": "functions-framework --signature-type=openfunction --target=tryKnativeAsync" } ```
### Google Cloud Functions
Expand Down Expand Up @@ -243,5 +288,3 @@ Contributions to this library are welcome and encouraged. See [ff_node_unit_link]: https://github.com/openfunction/functions-framework-nodejs/actions?query=workflow%3A"Node.js+Unit+CI" [ff_node_lint_img]: https://github.com/openfunction/functions-framework-nodejs/workflows/Node.js%20Lint%20CI/badge.svg [ff_node_lint_link]: https://github.com/openfunction/functions-framework-nodejs/actions?query=workflow%3A"Node.js+Lint+CI" [ff_node_conformance_img]: https://github.com/openfunction/functions-framework-nodejs/workflows/Node.js%20Conformance%20CI/badge.svg [ff_node_conformance_link]: https://github.com/openfunction/functions-framework-nodejs/actions?query=workflow%3A"Node.js+Conformance+CI"