Dapr - Pub Sub Redis

Subscribe to Redis Streams

Self-Hosted

1. Add app.UseCloudEvents and endpoints.MapSubscribeHandler in Configure method of Startup.cs

   public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
   {
       ......
       app.UseCloudEvents();
       app.UseEndpoints(endpoints =>
       {
      endpoints.MapControllers();
      endpoints.MapSubscribeHandler();
       });
   }
   

2. Create a yaml file in components folder

   apiVersion: dapr.io/v1alpha1
   kind: Component
   metadata:
     name: pubsub
   spec:
     type: pubsub.redis
     version: v1
     metadata:
     - name: redisHost
       value: localhost:6379
     - name: redisPassword
       value: ""
   

3. Create a controller for Email

   using Dapr;
   using Dapr.Client;
   ......
   namespace HTTPSendGrid.Controllers
   {
       [ApiController]
       [Route("[controller]")]
       public class EmailController : ControllerBase
       {
      ......
           
      private readonly DaprClient _daprClient;
      private readonly ILogger<EmailController> _logger;
   
      public EmailController(ILogger<EmailController> logger, DaprClient daprClient)
      {
          _logger = logger;
          _daprClient = daprClient;
      }
   
      ......
   
      [Topic("pubsub", "emailTopic")]
      [HttpPost("PubSubSend")]
      public Task PubSubSendEmail(EmailModel email)
      {
          _logger.LogInformation($"PubSubSend Email {email.Subject} to {email.To}");
          return SendEmail(email);
      }
   
      ......
       }
   }
   

   NOTE: pubsubName comes from the component name of yaml file at #2

4. Run the application

   dapr run --app-id emailservice --components-path ./components --dapr-http-port 3500 --app-port 5001 --app-ssl -- dotnet run
   

5. Invoke the service via curl

   curl --location --request POST 'http://localhost:3500/v1.0/publish/pubsub/emailTopic' \
   --header 'Content-Type: application/json' \
   --data-raw '{
       "from": "no-reply@test.com",
       "to": "yourname@test.com",
       "subject": "Hello Dapr SendGrid",
       "body": "<h1>Hello from Dapr PubSub</h1>"
   }'
   

   NOTE: Url pattern: /v1.0/publish/[pubsubName]/[topicName]

Kubernetes

1. Install Redis in Kubernetes

   helm repo add bitnami https://charts.bitnami.com/bitnami
   helm install redis bitnami/redis
   

2. Check the Redis containers and get Redis password Windows:
   • Will create a file with your encoded password

     kubectl get secret --namespace default redis -o jsonpath="{.data.redis-password}" > encoded.b64
     

   • Will put your redis password in a text file called password.txt

     certutil -decode encoded.b64 password.txt
     

3. Create a yaml file for pubsub component in k8s folder

   apiVersion: dapr.io/v1alpha1
   kind: Component
   metadata:
     name: pubsub
   spec:
     type: pubsub.redis
     version: v1
     metadata:
     - name: redisHost
       value: redis-master:6379
     - name: redisPassword
       value: "GENERATE_AT_2"
   

4. Deploy pubsub component to Kubernetes
5. Create a Dockerfile

   FROM mcr.microsoft.com/dotnet/aspnet:5.0 AS base
   WORKDIR /app
   EXPOSE 80
   EXPOSE 443
   

   FROM mcr.microsoft.com/dotnet/sdk:5.0 AS build
   WORKDIR /src
   COPY ["HTTPSendGrid.csproj", "."]
   RUN dotnet restore "./HTTPSendGrid.csproj"
   COPY . .
   WORKDIR "/src/."
   RUN dotnet build "HTTPSendGrid.csproj" -c Release -o /app/build
   

   FROM build AS publish
   RUN dotnet publish "HTTPSendGrid.csproj" -c Release -o /app/publish
   

   FROM base AS final
   WORKDIR /app
   COPY --from=publish /app/publish .
   ENTRYPOINT ["dotnet", "HTTPSendGrid.dll"]
   

6. Docker build

   docker build -t httpsendgrid:latest .
   

7. Create a yaml file and deploy container to Kubernetes

   kind: Deployment
   apiVersion: apps/v1
   metadata:
     name: sendgrid-app
     namespace: default
     labels:
       app: sendgrid-app
   spec:
     ......
     template:
       metadata:
    labels:
      app: sendgrid-app
    annotations:
      dapr.io/enabled: "true"
      dapr.io/app-id: "emailservice"
      dapr.io/app-port: "80"
      dapr.io/log-level: "debug"
   ......
   

8. Invoke the Kubernetes NodePort via curl

     curl --location --request POST 'http://localhost:30040/v1.0/publish/pubsub/emailTopic' \
   --header 'Content-Type: application/json' \
   --data-raw '{
       "from": "no-reply@test.com",
       "to": "yourname@test.com",
       "subject": "Hello Dapr SendGrid K8S",
       "body": "<h1>Hello from Dapr PubSub</h1>"
   }'