mirror of https://github.com/dapr/docs.git
68 lines
2.4 KiB
Markdown
68 lines
2.4 KiB
Markdown
---
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type: docs
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title: "How-To: Use bindings to interface with external resources"
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linkTitle: "How-To: Bindings"
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description: "Invoke external systems with Dapr output bindings"
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weight: 300
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---
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Using bindings, it is possible to invoke external resources without tying in to special SDK or libraries.
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For a complete sample showing output bindings, visit this [link](https://github.com/dapr/quickstarts/tree/master/bindings).
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Watch this [video](https://www.youtube.com/watch?v=ysklxm81MTs&feature=youtu.be&t=1960) on how to use bi-directional output bindings.
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## 1. Create a binding
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An output binding represents a resource that Dapr will use invoke and send messages to.
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For the purpose of this guide, you'll use a Kafka binding. You can find a list of the different binding specs [here]({{< ref bindings >}}).
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Create the following YAML file, named binding.yaml, and save this to a `components` sub-folder in your application directory.
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(Use the `--components-path` flag with `dapr run` to point to your custom components dir)
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*Note: When running in Kubernetes, apply this file to your cluster using `kubectl apply -f binding.yaml`*
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```yaml
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apiVersion: dapr.io/v1alpha1
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kind: Component
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metadata:
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name: myevent
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namespace: default
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spec:
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type: bindings.kafka
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version: v1
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metadata:
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- name: brokers
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value: localhost:9092
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- name: publishTopic
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value: topic1
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```
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Here, create a new binding component with the name of `myevent`.
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Inside the `metadata` section, configure Kafka related properties such as the topic to publish the message to and the broker.
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## 2. Send an event
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All that's left now is to invoke the bindings endpoint on a running Dapr instance.
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You can do so using HTTP:
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```bash
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curl -X POST -H http://localhost:3500/v1.0/bindings/myevent -d '{ "data": { "message": "Hi!" }, "operation": "create" }'
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```
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As seen above, you invoked the `/binding` endpoint with the name of the binding to invoke, in our case its `myevent`.
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The payload goes inside the mandatory `data` field, and can be any JSON serializable value.
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You'll also notice that there's an `operation` field that tells the binding what you need it to do.
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You can check [here]({{< ref bindings >}}) which operations are supported for every output binding.
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## References
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- [Binding API]({{< ref bindings_api.md >}})
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- [Binding components]({{< ref bindings >}})
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- [Binding detailed specifications]({{< ref supported-bindings >}})
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