Middleware pipelines

Custom processing pipelines of chained middleware components

Dapr allows custom processing pipelines to be defined by chaining a series of middleware components. A request goes through all defined middleware components before it’s routed to user code, and then goes through the defined middleware, in reverse order, before it’s returned to the client, as shown in the following diagram.

Middleware - 图1

Customize processing pipeline

When launched, a Dapr sidecar constructs a middleware processing pipeline. By default the pipeline consists of tracing middleware and CORS middleware. Additional middleware, configured by a Dapr configuration, can be added to the pipeline in the order they are defined. The pipeline applies to all Dapr API endpoints, including state, pub/sub, service invocation, bindings, security and others.

NOTE: Dapr provides a middleware.http.uppercase pre-registered component that changes all text in a request body to uppercase. You can use it to test/verify if your custom pipeline is in place.

The following configuration example defines a custom pipeline that uses a OAuth 2.0 middleware and an uppercase middleware component. In this case, all requests are authorized through the OAuth 2.0 protocol, and transformed to uppercase text, before they are forwarded to user code.

  1. apiVersion: dapr.io/v1alpha1
  2. kind: Configuration
  3. metadata:
  4.   name: pipeline
  5.   namespace: default
  6. spec:
  7.   httpPipeline:
  8.     handlers:
  9.     - name: oauth2
  10.       type: middleware.http.oauth2
  11.     - name: uppercase
  12.       type: middleware.http.uppercase

Next steps

Last modified March 18, 2021: Merge pull request #1321 from dapr/aacrawfi/logos (9a399d5)