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Pupsub updates

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---
type: docs
title: "How-To: Publish message to a topic"
linkTitle: "How-To: Publish"
weight: 2000
description: "Send messages to subscribes through topics"
---
Pub/Sub is a common pattern in a distributed system with many services that want to utilize decoupled, asynchronous messaging.
Using Pub/Sub, you can enable scenarios where event consumers are decoupled from event producers.
Dapr provides an extensible Pub/Sub system with At-Least-Once guarantees, allowing developers to publish and subscribe to topics.
Dapr provides different implementation of the underlying system, and allows operators to bring in their preferred infrastructure, for example Redis Streams, Kafka, etc.
## Setup the Pub/Sub component
The first step is to setup the Pub/Sub component.
For this guide, we'll use Redis Streams, which is also installed by default on a local machine when running `dapr init`.
*Note: When running Dapr locally, a pub/sub component YAML is automatically created for you locally. To override, create a `components` directory containing the file and use the flag `--components-path` with the `dapr run` CLI command.*
```yaml
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
name: pubsub-name
namespace: default
spec:
type: pubsub.redis
metadata:
- name: redisHost
value: localhost:6379
- name: redisPassword
value: ""
- name: allowedTopics
value: "deathStartStatus"
```
Using the `allowedTopics` you can specify that only the `deathStartStatus` topic should be supported.
To deploy this into a Kubernetes cluster, fill in the `metadata` connection details in the yaml, and run `kubectl apply -f pubsub.yaml`.
## Publish a topic
To publish a message to a topic, invoke the following endpoint on a Dapr instance:
```bash
curl -X POST http://localhost:3500/v1.0/publish/pubsub-name/deathStarStatus \
-H "Content-Type: application/json" \
-d '{
"status": "completed"
}'
```
The above example publishes a JSON payload to a `deathStartStatus` topic.
Dapr wraps the user payload in a Cloud Events v1.0 compliant envelope.

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---
type: docs
title: "How-To: Publish message and subscribe to a topic"
linkTitle: "How-To: Publish & subscribe"
weight: 2000
description: "Learn how to send messages to a topic with one service and subscribe to that topic in another service"
---
## Introduction
Pub/Sub is a common pattern in a distributed system with many services that want to utilize decoupled, asynchronous messaging.
Using Pub/Sub, you can enable scenarios where event consumers are decoupled from event producers.
Dapr provides an extensible Pub/Sub system with At-Least-Once guarantees, allowing developers to publish and subscribe to topics.
Dapr provides different implementation of the underlying system, and allows operators to bring in their preferred infrastructure, for example Redis Streams, Kafka, etc.
## Step 1: Setup the Pub/Sub component
The first step is to setup the Pub/Sub component:
{{< tabs "Self-Hosted (CLI)" Kubernetes >}}
{{% codetab %}}
Redis Streams is installed by default on a local machine when running `dapr init`.
Verify by opening your components file under `%UserProfile%\.dapr\components\pubsub.yaml` on Windows or `~/.dapr/components/pubsub.yaml` on Linux/MacOS:
```yaml
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
name: pubsub
spec:
type: pubsub.redis
metadata:
- name: redisHost
value: localhost:6379
- name: redisPassword
value: ""
```
You can override this file with another Redis instance or another [pubsub component]({{< ref setup-pubsub >}}) by creating a `components` directory containing the file and using the flag `--components-path` with the `dapr run` CLI command.
{{% /codetab %}}
{{% codetab %}}
To deploy this into a Kubernetes cluster, fill in the `metadata` connection details of your [desired pubsub component]({{< ref setup-pubsub >}}) in the yaml below, save as `pubsub.yaml`, and run `kubectl apply -f pubsub.yaml`.
```yaml
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
name: pubsub
namespace: default
spec:
type: pubsub.redis
metadata:
- name: redisHost
value: localhost:6379
- name: redisPassword
value: ""
```
{{% /codetab %}}
{{< /tabs >}}
## Step 2: Publish a topic
To publish a message to a topic, invoke the following endpoint on a Dapr instance:
{{< tabs "HTTP API (Bash)" "HTTP API (PowerShell)">}}
{{% codetab %}}
Begin by ensuring a Dapr sidecar is running:
```bash
dapr --app-id myapp --port 3500 run
```
Then publish a message to the `deathStarStatus` topic:
```bash
curl -X POST http://localhost:3500/v1.0/publish/pubsub/deathStarStatus -H "Content-Type: application/json" -d '{"status": "completed"}'
```
{{% /codetab %}}
{{% codetab %}}
Begin by ensuring a Dapr sidecar is running:
```bash
dapr --app-id myapp --port 3500 run
```
Then publish a message to the `deathStarStatus` topic:
```powershell
Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '{"status": "completed"}' -Uri 'http://localhost:3500/v1.0/publish/pubsub/deathStarStatus'
```
{{% /codetab %}}
{{< /tabs >}}
Dapr automatically wraps the user payload in a Cloud Events v1.0 compliant envelope.
## Step 3: Subscribe to topics
Dapr allows two methods by which you can subscribe to topics:
- **Declaratively**, where subscriptions are are defined in an external file.
- **Programatically**, where subscriptions are defined in user code
### Declarative subscriptions
You can subscribe to a topic using the following Custom Resources Definition (CRD):
```yaml
apiVersion: dapr.io/v1alpha1
kind: Subscription
metadata:
name: myevent-subscription
spec:
topic: deathStarStatus
route: /dsstatus
pubsubname: pubsub
scopes:
- app1
- app2
```
The example above shows an event subscription to topic `deathStarStatus`, for the pubsub component `pubsub`.
The `route` field tells Dapr to send all topic messages to the `/dsstatus` endpoint in the app.
The `scopes` field enables this subscription for apps with IDs `app1` and `app2`.
Set the component with:
{{< tabs "Self-Hosted (CLI)" Kubernetes>}}
{{% codetab %}}
Place the CRD in your `./components` directory. When Dapr starts up, it will load subscriptions along with components.
You can also override the default directory by pointing the Dapr CLI to a components path:
```bash
dapr run --app-id myapp --components-path ./myComponents -- python3 myapp.py
```
*Note: By default, Dapr loads components from `$HOME/.dapr/components` on MacOS/Linux and `%USERPROFILE%\.dapr\components` on Windows. If you place the subscription in a custom components path, make sure the Pub/Sub component is present also.*
{{% /codetab %}}
{{% codetab %}}
In Kubernetes, save the CRD to a file and apply it to the cluster:
```bash
kubectl apply -f subscription.yaml
```
{{% /codetab %}}
{{< /tabs >}}
#### Example
After setting up the subscription above, download this javascript into a `app1.js` file:
```javascript
const express = require('express')
const bodyParser = require('body-parser')
const app = express()
app.use(bodyParser.json())
const port = 3000
app.post('/dsstatus', (req, res) => {
res.sendStatus(200);
});
app.listen(port, () => console.log(`consumer app listening on port ${port}!`))
```
Run this app with:
```bash
dapr --app-id app1 --app-port 3000 run node app1.js
```
### Programmatic subscriptions
To subscribe to topics, start a web server in the programming language of your choice and listen on the following `GET` endpoint: `/dapr/subscribe`.
The Dapr instance will call into your app at startup and expect a JSON response for the topic subscriptions with:
- `pubsubname`: Which pub/sub component Dapr should use
- `topic`: Which topic to subscribe to
- `route`: Which endpoint for Dapr to call on when a message comes to that topic
#### Example
*Note: The following example is written in Node.js, but can be in any programming language*
```javascript
const express = require('express')
const bodyParser = require('body-parser')
const app = express()
app.use(bodyParser.json())
const port = 3000
app.get('/dapr/subscribe', (req, res) => {
res.json([
{
pubsubname: "pubsub",
topic: "deathStarStatus",
route: "dsstatus"
}
]);
})
app.post('/dsstatus', (req, res) => {
res.sendStatus(200);
});
app.listen(port, () => console.log(`consumer app listening on port ${port}!`))
```
The `/dsstatus` endpoint matches the `route` defined in the subscriptions and this is where Dapr will send all topic messages to.
## Step 4: ACK-ing a message
In order to tell Dapr that a message was processed successfully, return a `200 OK` response. If Dapr receives any other return status code than `200`, or if your app crashes, Dapr will attempt to redeliver the message following At-Least-Once semantics.
#### Example
*Note: The following example is written in Node.js, but can be in any programming language*
```javascript
app.post('/dsstatus', (req, res) => {
res.sendStatus(200);
});
```

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---
type: docs
title: "How-To: Subscribe to a topic"
linkTitle: "How-To: Subscribe"
weight: 3000
description: "Consume messages from topics"
---
Pub/Sub is a very common pattern in a distributed system with many services that want to utilize decoupled, asynchronous messaging.
Using Pub/Sub, you can enable scenarios where event consumers are decoupled from event producers.
Dapr provides an extensible Pub/Sub system with At-Least-Once guarantees, allowing developers to publish and subscribe to topics.
Dapr provides different implementation of the underlying system, and allows operators to bring in their preferred infrastructure, for example Redis Streams, Kafka, etc.
Watch this [video](https://www.youtube.com/watch?v=NLWukkHEwGA&feature=youtu.be&t=1052) on how to consume messages from topics.
## Setup the Pub Sub component
The first step is to setup the Pub/Sub component.
For this guide, we'll use Redis Streams, which is also installed by default on a local machine when running `dapr init`.
*Note: When running Dapr locally, a pub/sub component YAML is automatically created for you locally. To override, create a `components` directory containing the file and use the flag `--components-path` with the `dapr run` CLI command.*
```yaml
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
name: pubsub
namespace: default
spec:
type: pubsub.redis
metadata:
- name: redisHost
value: localhost:6379
- name: redisPassword
value: ""
```
To deploy this into a Kubernetes cluster, fill in the `metadata` connection details in the yaml, and run `kubectl apply -f pubsub.yaml`.
## Subscribe to topics
Dapr allows two methods by which you can subscribe to topics: programatically, where subscriptions are defined in user code and declaratively, where subscriptions are are defined in an external file.
### Declarative subscriptions
You can subscribe to a topic using the following Custom Resources Definition (CRD):
```yaml
apiVersion: dapr.io/v1alpha1
kind: Subscription
metadata:
name: myevent-subscription
spec:
topic: newOrder
route: /orders
pubsubname: kafka
scopes:
- app1
- app2
```
The example above shows an event subscription to topic `newOrder`, for the pubsub component `kafka`.
The `route` field tells Dapr to send all topic messages to the `/orders` endpoint in the app.
The `scopes` field enables this subscription for apps with IDs `app1` and `app2`.
An example of a node.js app that receives events from the subscription:
```javascript
const express = require('express')
const bodyParser = require('body-parser')
const app = express()
app.use(bodyParser.json())
const port = 3000
app.post('/orders', (req, res) => {
res.sendStatus(200);
});
app.listen(port, () => console.log(`consumer app listening on port ${port}!`))
```
#### Subscribing on Kubernetes
In Kubernetes, save the CRD to a file and apply it to the cluster:
```
kubectl apply -f subscription.yaml
```
#### Subscribing in Self Hosted
When running Dapr in Self-hosted, either locally or on a VM, put the CRD in your `./components` directory.
When Dapr starts up, it will load subscriptions along with components.
The following example shows how to point the Dapr CLI to a components path:
```
dapr run --app-id myapp --components-path ./myComponents -- python3 myapp.py
```
*Note: By default, Dapr loads components from $HOME/.dapr/components on MacOS/Linux and %USERPROFILE%\.dapr\components on Windows. If you place the subscription in a custom components path, make sure the Pub/Sub component is present also.*
### Programmatic subscriptions
To subscribe to topics, start a web server in the programming language of your choice and listen on the following `GET` endpoint: `/dapr/subscribe`.
The Dapr instance will call into your app, and expect a JSON response for the topic subscriptions.
*Note: The following example is written in node, but can be in any programming language*
<pre>
const express = require('express')
const bodyParser = require('body-parser')
const app = express()
app.use(bodyParser.json())
const port = 3000
<b>app.get('/dapr/subscribe', (req, res) => {
res.json([
{
pubsubname: "pubsub",
topic: "newOrder",
route: "orders"
}
]);
})</b>
app.post('/orders', (req, res) => {
res.sendStatus(200);
});
app.listen(port, () => console.log(`consumer app listening on port ${port}!`))
</pre>
In the payload returned to Dapr, `topic` tells Dapr which topic to subscribe to, `route` tells Dapr which endpoint to call on when a message comes to that topic, and `pubsubName` tells Dapr which pub/sub component it should use. In this example this is `pubsub` as this is the name of the component we outlined above.
The `/orders` endpoint matches the `route` defined in the subscriptions and this is where Dapr will send all topic messages to.
### ACK-ing a message
In order to tell Dapr that a message was processed successfully, return a `200 OK` response:
```javascript
res.status(200).send()
```
### Schedule a message for redelivery
If Dapr receives any other return status code than `200`, or if your app crashes, Dapr will attempt to redeliver the message following At-Least-Once semantics.

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--- ---
type: docs type: docs
title: "Pub/Sub overview" title: "Publish/Subscribe overview"
linkTitle: "Pub/Sub overview" linkTitle: "Overview"
weight: 1000 weight: 1000
description: "Overview of the Dapr Pub/Sub building block" description: "Overview of the Dapr Pub/Sub building block"
--- ---
## Introduction
The [publish/subscribe pattern](https://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern) allows your microservices to communicate with each other purely by sending messages. In this system, the **producer** of a message sends it to a **topic**, with no knowledge of what service will receive the message. A messages can even be sent if there's no consumer for it. The [publish/subscribe pattern](https://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern) allows your microservices to communicate with each other purely by sending messages. In this system, the **producer** of a message sends it to a **topic**, with no knowledge of what service will receive the message. A messages can even be sent if there's no consumer for it.
Similarly, a **consumer** will receive messages from a topic without knowledge of what producer sent it. This pattern is especially useful when you need to decouple microservices from one another. Similarly, a **consumer** will receive messages from a topic without knowledge of what producer sent it. This pattern is especially useful when you need to decouple microservices from one another.
Dapr provides a publish/subscribe API that provides at-least-once guarantees and integrates with various message brokers implementations. These implementations are pluggable, and developed outside of the Dapr runtime in [components-contrib](https://github.com/dapr/components-contrib/tree/master/pubsub). Dapr provides a publish/subscribe API that provides at-least-once guarantees and integrates with various message brokers implementations. These implementations are pluggable, and developed outside of the Dapr runtime in [components-contrib](https://github.com/dapr/components-contrib/tree/master/pubsub).
## Publish/Subscribe API ## Features
The API for Publish/Subscribe can be found in the [spec repo](../../reference/api/pubsub_api.md). ### Publish/Subscribe API
## Behavior and guarantees The API for Publish/Subscribe can be found in the [spec repo]({{< ref pubsub_api.md >}}).
### At-Least-Once guarantee
Dapr guarantees At-Least-Once semantics for message delivery. Dapr guarantees At-Least-Once semantics for message delivery.
That means that when an application publishes a message to a topic using the Publish/Subscribe API, it can assume the message is delivered at least once to any subscriber when the response status code from that endpoint is `200`, or returns no error if using the gRPC client. That means that when an application publishes a message to a topic using the Publish/Subscribe API, it can assume the message is delivered at least once to any subscriber when the response status code from that endpoint is `200`, or returns no error if using the gRPC client.
### Consumer groups and multiple instances
The burden of dealing with concepts like consumer groups and multiple instances inside consumer groups is all catered for by Dapr. The burden of dealing with concepts like consumer groups and multiple instances inside consumer groups is all catered for by Dapr.
### App ID
Dapr has the concept of an `id`. This is specified in Kubernetes using the `dapr.io/app-id` annotation and with the `app-id` flag using the Dapr CLI. Dapr requires an ID to be assigned to every application.
When multiple instances of the same application ID subscribe to a topic, Dapr will make sure to deliver the message to only one instance. If two different applications with different IDs subscribe to a topic, at least one instance in each application receives a copy of the same message. When multiple instances of the same application ID subscribe to a topic, Dapr will make sure to deliver the message to only one instance. If two different applications with different IDs subscribe to a topic, at least one instance in each application receives a copy of the same message.
## Cloud events ### Cloud events
Dapr follows the [CloudEvents 1.0 Spec](https://github.com/cloudevents/spec/tree/v1.0) and wraps any payload sent to a topic inside a Cloud Events envelope. Dapr follows the [CloudEvents 1.0 Spec](https://github.com/cloudevents/spec/tree/v1.0) and wraps any payload sent to a topic inside a Cloud Events envelope.
The following fields from the Cloud Events spec are implemented with Dapr: The following fields from the Cloud Events spec are implemented with Dapr:
- `id`
* `id` - `source`
* `source` - `specversion`
* `specversion` - `type`
* `type` - `datacontenttype` (Optional)
* `datacontenttype` (Optional)
> Starting with Dapr v0.9, Dapr no longer wraps published content into CloudEvent if the published payload itself is already in CloudEvent format. > Starting with Dapr v0.9, Dapr no longer wraps published content into CloudEvent if the published payload itself is already in CloudEvent format.
The following example shows an XML content in CloudEvent v1.0 serialized as JSON: The following example shows an XML content in CloudEvent v1.0 serialized as JSON:
```json ```json
{ {
"specversion" : "1.0", "specversion" : "1.0",
@ -59,3 +57,12 @@ The following example shows an XML content in CloudEvent v1.0 serialized as JSON
"data" : "<note><to>User1</to><from>user2</from><message>hi</message></note>" "data" : "<note><to>User1</to><from>user2</from><message>hi</message></note>"
} }
``` ```
### Topic scoping
Limit which topics applications are able to publish/subscibe to in order to limit access to potentially sensitive data streams. Read [Pub/Sub scoping]({{< ref pubsub-scopes.md >}}) for more information.
## Next steps
- Read the How-To guide on [publishing and subscribing]({{< ref howto-publish-subscribe.md >}})
- Learn about [Pub/Sub scopes]({{< ref pubsub-scopes.md >}})

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--- ---
type: docs type: docs
title: "How To: Scope Pub/Sub topics" title: "Scope Pub/Sub topic access"
linkTitle: "How To: Scope topics" linkTitle: "Scope topic access"
weight: 5000 weight: 5000
description: "Use scopes to limit Pub/Sub topics to specific applications" description: "Use scopes to limit Pub/Sub topics to specific applications"
--- ---
[Namespaces or component scopes](../components-scopes/README.md) can be used to limit component access to particular applications. These application scopes added to a component limit only the applications with specific IDs to be able to use the component. ## Introduction
[Namespaces or component scopes]({{< ref component-scopes.md >}}) can be used to limit component access to particular applications. These application scopes added to a component limit only the applications with specific IDs to be able to use the component.
In addition to this general component scope, the following can be limited for pub/sub components: In addition to this general component scope, the following can be limited for pub/sub components:
- the topics which can be used (published or subscribed) - Which topics which can be used (published or subscribed)
- which applications are allowed to publish to specific topics - Which applications are allowed to publish to specific topics
- which applications are allowed to subscribe to specific topics - Which applications are allowed to subscribe to specific topics
This is called pub/sub topic scoping. This is called **pub/sub topic scoping**.
Watch this [video](https://www.youtube.com/watch?v=7VdWBBGcbHQ&feature=youtu.be&t=513) on how to use pub/sub topic scoping. Pub/sub scopes are defined for each pub/sub component. You may have a pub/sub component named `pubsub` that has one set of scopes, and another `pubsub2` with a different set.
To use this topic scoping, three metadata properties can be set for a pub/sub component: To use this topic scoping three metadata properties can be set for a pub/sub component:
- ```spec.metadata.publishingScopes```: the list of applications to topic scopes to allow publishing, separated by semicolons. If an app is not specified in ```publishingScopes```, its allowed to publish to all topics. - `spec.metadata.publishingScopes`
- ```spec.metadata.subscriptionScopes```: the list of applications to topic scopes to allow subscription, separated by semicolons. If an app is not specified in ```subscriptionScopes```, its allowed to subscribe to all topics. - A semicolon-separated list of applications & comma-separated topic lists, allowing that app to publish to that list of topics
- ```spec.metadata.allowedTopics```: a comma-separated list for allowed topics for all applications. ```publishingScopes``` or ```subscriptionScopes``` can be used in addition to add granular limitations. If ```allowedTopics``` is not set, all topics are valid and then ```subscriptionScopes``` and ```publishingScopes``` take place if present. - If nothing is specified in `publishingScopes` (default behavior), all apps can publish to all topics
- To deny an app the ability to publish to any topic, leave the topics list blank (`app1=;app2=topic2`)
- For example, `app1=topic1;app2=topic2,topic3;app3=` will allow app1 to publish to topic1 and nothing else, app2 to publish to topic2 and topic3 only, and app3 to publish to nothing.
- `spec.metadata.subscriptionScopes`
- A semicolon-separated list of applications & comma-separated topic lists, allowing that app to subscribe to that list of topics
- If nothing is specified in `subscriptionScopes` (default behavior), all apps can subscribe to all topics
- For example, `app1=topic1;app2=topic2,topic3` will allow app1 to subscribe to topic1 only and app2 to subscribe to topic2 and topic3
- `spec.metadata.allowedTopics`
- A comma-separated list of allowed topics for all applications.
- If `allowedTopics` is not set (default behavior), all topics are valid. `subscriptionScopes` and `publishingScopes` still take place if present.
- `publishingScopes` or `subscriptionScopes` can be used in conjuction with `allowedTopics` to add granular limitations
These metadata properties can be used for all pub/sub components. The following examples use Redis as pub/sub component. These metadata properties can be used for all pub/sub components. The following examples use Redis as pub/sub component.
## Scenario 1: Limit which application can publish or subscribe to topics ## Example 1: Scope topic access
This can be useful, if you have topics which contain sensitive information and only a subset of your applications are allowed to publish or subscribe to these. Limiting which applications can publish/subscribe to topics can be useful if you have topics which contain sensitive information and only a subset of your applications are allowed to publish or subscribe to these.
It can also be used for all topics to have always a "ground truth" for which applications are using which topics as publishers/subscribers. It can also be used for all topics to have always a "ground truth" for which applications are using which topics as publishers/subscribers.
@ -50,29 +62,31 @@ spec:
value: "app2=;app3=topic1" value: "app2=;app3=topic1"
``` ```
The table below shows which application is allowed to publish into the topics: The table below shows which applications are allowed to publish into the topics:
| Publishing | app1 | app2 | app3 |
|------------|------|------|------|
| topic1 | X | | |
| topic2 | | X | |
| topic3 | | X | |
The table below shows which application is allowed to subscribe to the topics: | | topic1 | topic2 | topic3 |
| Subscription | app1 | app2 | app3 | |------|--------|--------|--------|
|--------------|------|------|------| | app1 | X | | |
| topic1 | X | | X | | app2 | | X | X |
| topic2 | X | | | | app3 | | | |
| topic3 | X | | |
> Note: If an application is not listed (e.g. app1 in subscriptionScopes), it is allowed to subscribe to all topics. Because ```allowedTopics``` (see below of examples) is not used and app1 does not have any subscription scopes, it can also use additional topics not listed above. The table below shows which applications are allowed to subscribe to the topics:
## Scenario 2: Limit which topics can be used by all applications without granular limitations | | topic1 | topic2 | topic3 |
|------|--------|--------|--------|
| app1 | X | X | X |
| app2 | | | |
| app3 | X | | |
A topic is created if a Dapr application sends a message to it. In some scenarios this topic creation should be governed. For example; > Note: If an application is not listed (e.g. app1 in subscriptionScopes) it is allowed to subscribe to all topics. Because `allowedTopics` is not used and app1 does not have any subscription scopes, it can also use additional topics not listed above.
- a bug in a Dapr application on generating the topic name can lead to an unlimited amount of topics created
- streamline the topics names and total count and prevent an unlimited growth of topics
In these situations, ```allowedTopics``` can be used. ## Example 2: Limit allowed topics
A topic is created if a Dapr application sends a message to it. In some scenarios this topic creation should be governed. For example:
- A bug in a Dapr application on generating the topic name can lead to an unlimited amount of topics created
- Streamline the topics names and total count and prevent an unlimited growth of topics
In these situations `allowedTopics` can be used.
Here is an example of three allowed topics: Here is an example of three allowed topics:
```yaml ```yaml
@ -94,7 +108,7 @@ spec:
All applications can use these topics, but only those topics, no others are allowed. All applications can use these topics, but only those topics, no others are allowed.
## Scenario 3: Combine both allowed topics allowed applications that can publish and subscribe ## Example 3: Combine `allowedTopics` and scopes
Sometimes you want to combine both scopes, thus only having a fixed set of allowed topics and specify scoping to certain applications. Sometimes you want to combine both scopes, thus only having a fixed set of allowed topics and specify scoping to certain applications.
@ -123,17 +137,22 @@ spec:
> Note: The third application is not listed, because if an app is not specified inside the scopes, it is allowed to use all topics. > Note: The third application is not listed, because if an app is not specified inside the scopes, it is allowed to use all topics.
The table below shows which application is allowed to publish into the topics: The table below shows which application is allowed to publish into the topics:
| Publishing | app1 | app2 | app3 |
|------------|------|------|------| | | A | B | C |
| A | X | X | X | |------|---|---|---|
| B | | X | X | | app1 | X | | |
| app2 | X | X | |
| app3 | X | X | |
The table below shows which application is allowed to subscribe to the topics: The table below shows which application is allowed to subscribe to the topics:
| Subscription | app1 | app2 | app3 |
|--------------|------|------|------|
| A | | X | X |
| B | | | X |
No other topics can be used, only A and B. | | A | B | C |
|------|---|---|---|
| app1 | | | |
| app2 | X | | |
| app3 | X | X | |
Pub/sub scopes are per pub/sub. You may have pub/sub component named `pubsub` that has one set of scopes, and another `pubsub2` with a different set. The name is the `metadata.name` field in the yaml.
## Demo
<iframe width="560" height="315" src="https://www.youtube.com/embed/7VdWBBGcbHQ?start=513" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

17
daprdocs/content/en/developing-applications/building-blocks/state-management/howto-get-save-state.md
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@ -6,6 +6,8 @@ weight: 200
description: "Use key value pairs to persist a state" description: "Use key value pairs to persist a state"
--- ---
## Introduction
State management is one of the most common needs of any application: new or legacy, monolith or microservice. State management is one of the most common needs of any application: new or legacy, monolith or microservice.
Dealing with different databases libraries, testing them, handling retries and faults can be time consuming and hard. Dealing with different databases libraries, testing them, handling retries and faults can be time consuming and hard.
@ -42,6 +44,10 @@ Begin by ensuring a Dapr sidecar is running:
```bash ```bash
dapr --app-id myapp --port 3500 run dapr --app-id myapp --port 3500 run
``` ```
{{% alert title="Note" color="info" %}}
It is important to set an app-id, as the state keys are prefixed with this value. If you don't set it one is generated for you at runtime, and the next time you run the command a new one will be generated and you will no longer be able to access previously saved state.
{{% /alert %}}
Then in a separate terminal run: Then in a separate terminal run:
```bash ```bash
@ -55,6 +61,11 @@ Begin by ensuring a Dapr sidecar is running:
dapr --app-id myapp --port 3500 run dapr --app-id myapp --port 3500 run
``` ```
{{% alert title="Note" color="info" %}}
It is important to set an app-id, as the state keys are prefixed with this value. If you don't set it one is generated for you at runtime, and the next time you run the command a new one will be generated and you will no longer be able to access previously saved state.
{{% /alert %}}
Then in a separate terminal run: Then in a separate terminal run:
```powershell ```powershell
Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '[{ "key": "key1", "value": "value1"}, { "key": "key2", "value": "value2"}]' -Uri 'http://localhost:3500/v1.0/state/statestore' Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '[{ "key": "key1", "value": "value1"}, { "key": "key2", "value": "value2"}]' -Uri 'http://localhost:3500/v1.0/state/statestore'
@ -77,6 +88,12 @@ with DaprClient() as d:
``` ```
Run with `dapr run --app-id myapp run python state.py` Run with `dapr run --app-id myapp run python state.py`
{{% alert title="Note" color="info" %}}
It is important to set an app-id, as the state keys are prefixed with this value. If you don't set it one is generated for you at runtime, and the next time you run the command a new one will be generated and you will no longer be able to access previously saved state.
{{% /alert %}}
{{% /codetab %}} {{% /codetab %}}
{{< /tabs >}} {{< /tabs >}}

19
daprdocs/content/en/developing-applications/building-blocks/pubsub/pubsub-namespaces.md → daprdocs/content/en/operations/components/setup-pubsub/pubsub-namespaces.md
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@ -1,7 +1,7 @@
--- ---
type: docs type: docs
title: "Pub/Sub and namespaces" title: "Pub/Sub and namespaces"
linkTitle: "Pub/Sub and namespaces" linkTitle: "Kubernetes Namespaces"
weight: 4000 weight: 4000
description: "Use Dapr Pub/Sub with multiple namespaces" description: "Use Dapr Pub/Sub with multiple namespaces"
--- ---
@ -11,14 +11,15 @@ In some scenarios, applications can be spread across namespaces and share a queu
In this example, we will use the [PubSub sample](https://github.com/dapr/quickstarts/tree/master/pub-sub). Redis installation and the subscribers will be in `namespace-a` while the publisher UI will be on `namespace-b`. This solution should also work if Redis was installed on another namespace or if we used a managed cloud service like Azure ServiceBus. In this example, we will use the [PubSub sample](https://github.com/dapr/quickstarts/tree/master/pub-sub). Redis installation and the subscribers will be in `namespace-a` while the publisher UI will be on `namespace-b`. This solution should also work if Redis was installed on another namespace or if we used a managed cloud service like Azure ServiceBus.
The table below shows which resources are deployed to which namespaces: The table below shows which resources are deployed to which namespaces:
| Resource | namespace-a | namespace-b |
|-|-|-| | Resource | namespace-a | namespace-b |
| Redis master | X || |------------------------ |-------------|-------------|
| Redis slave | X || | Redis master | X | |
| Dapr's PubSub component | X | X | | Redis slave | X | |
| Node subscriber | X || | Dapr's PubSub component | X | X |
| Python subscriber | X || | Node subscriber | X | |
| React UI publisher | | X| | Python subscriber | X | |
| React UI publisher | | X |
## Pre-requisites ## Pre-requisites