mirror of https://github.com/dapr/docs.git
51 lines
1.6 KiB
Markdown
51 lines
1.6 KiB
Markdown
# Rate limiting an application
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A common scenario in distributed computing is to only allow for a given number of requests to execute concurrently.
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Using Dapr, you can control how many requests and events will invoke your application simultaneously.
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*Note that this rate limiting is guaranteed for every event that's coming from Dapr, meaning Pub/Sub events, direct invocation from other services, bindings events etc. Dapr can't enforce the concurrency policy on requests that are coming to your app externally.*
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## Setting max-concurrency
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Without using Dapr, a developer would need to create some sort of a semaphore in the application and take care of acquiring and releasing it.
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Using Dapr, there are no code changes needed to an app.
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### Setting max-concurrency in Kubernetes
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To set max-concurrency in Kubernetes, add the following annotation to your pod:
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```yaml
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: nodesubscriber
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namespace: default
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labels:
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app: nodesubscriber
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spec:
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replicas: 1
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selector:
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matchLabels:
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app: nodesubscriber
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template:
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metadata:
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labels:
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app: nodesubscriber
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annotations:
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dapr.io/enabled: "true"
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dapr.io/id: "nodesubscriber"
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dapr.io/port: "3000"
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<b>dapr.io/max-concurrency: "1"</b>
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...
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```
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### Setting max-concurrency using the Dapr CLI
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To set max-concurrency with the Dapr CLI for running on your local dev machine, add the `max-concurrency` flag:
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```bash
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dapr run --max-concurrency 1 --app-port 5000 python ./app.py
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```
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The above examples will effectively turn your app into a single concurrent service.
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