TABLE 1
Building block	Description
State management	Support contextual information for long running stateful services.
Service invocation	Invoke direct, secure service-to-service calls using platform agnostic protocols and well-known endpoints.
Publish and subscribe	Implement secure, scalable pub/sub messaging between services.
Bindings	Trigger code from events raised by external resources with bi-directional communication.
Observability	Monitor and measure message calls across networked services.
Secrets	Securely access external secret stores.
Actors	Encapsulate logic and data in reusable actor objects.

表 1
构建基块	说明
状态管理	支持长时间运行有状态服务的上下文信息。
服务调用	使用平台无关协议和众所周知的终结点，进行直接安全的服务间调用。
发布和订阅	在服务之间实现安全的可伸缩的发布/订阅消息传送。
绑定	通过双向通信，外部资源触发事件时执行相关代码（或从服务内部反方向通知外部资源）
可观察性	监视和度量跨网络服务的消息调用。
机密	安全访问外部机密存储。
执行组件（参与者）	在可重用的执行组件（参与者）对象中封装逻辑和数据。

Building blocks abstract the implementation of distributed application capabilities from your services. Figure 2-3 shows this interaction.

构建块从服务中抽象化分布式应用程序功能的实现。图 2-3 显示了这种交互。

Figure 2-3. Dapr building block integration.

图 2-3。Dapr 构建块集成。

Building blocks invoke Dapr components that provide the concrete implementation for each resource. The code for your service is only aware of the building block. It takes no dependencies on external SDKs or libraries - Dapr handles the plumbing for you. Each building block is independent. You can use one, some, or all of them in your application. As a value-add, Dapr building blocks bake in industry best practices including comprehensive observability.

构建块调用 Dapr 组件，这些组件提供每个资源的具体实现。服务的代码仅知道构建块。它不需要依赖于外部 SDK 或库 - Dapr 会处理管道。每个构建块都是独立的。可以在应用程序中使用其中一个、一部分或全部构建块。作为一种附加值，Dapr 构建块产生于行业最佳实践中（包括全面的可观测性）。

We provide detailed explanation and code samples for each Dapr building block in the upcoming chapters. At this point, the jet descends even more. From the new perspective, you now have a closer look at the Dapr components layer.

在即将发布的章节中，我们将提供每个 Dapr 构建块的详细说明和代码示例。此时，飞机下降了更多。从新视角，现在更深入地了解了 Dapr 组件层。

Components

组件

While building blocks expose an API to invoke distributed application capabilities, Dapr components provide the concrete implementation to make it happen.

虽然构建块公开 API 以调用分布式应用程序功能，但 Dapr 组件提供了具体实现来支持。

Consider, the Dapr state store component. It provides a uniform way to manage state for CRUD operations. Without any change to your service code, you could switch between any of the following Dapr state components:

请考虑 Dapr 状态存储组件。它提供了一种统一的方式来管理 CRUD 操作的状态。无需更改服务代码，即可在下列任何 Dapr 状态组件之间切换：

Each component provides the necessary implementation through a common state management interface:

每个组件都通过通用状态管理接口提供必要的实现：

type Store interface {Init(metadata Metadata) errorDelete(req *DeleteRequest) errorBulkDelete(req []DeleteRequest) errorGet(req *GetRequest) (*GetResponse, error)Set(req *SetRequest) errorBulkSet(req []SetRequest) error
}

Tip

The Dapr runtime as well as all of the Dapr components have been written in the Golang, or Go, language. Go is a popular language across the open source community and attests to cross-platform commitment of Dapr.

提示

Dapr 运行时以及所有 Dapr 组件都使用 Go语言编写。Go是一种在开源社区中流行的语言，并证实 Dapr 的跨平台承诺。

Perhaps you start with Azure Redis Cache as your state store. You specify it with the following configuration:

或许你将 Azure Redis 缓存用作状态存储作为开始。使用以下配置指定它：

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:name: statestorenamespace: default
spec:type: state.redisversion: v1metadata:- name: redisHostvalue: <HOST>- name: redisPasswordvalue: <PASSWORD>- name: enableTLSvalue: <bool> # Optional. Allowed: true, false.- name: failovervalue: <bool> # Optional. Allowed: true, false.

In the spec p, you configure Dapr to use the Redis Cache for state management. The p also contains component-specific metadata. In this case, you can use it to configure additional Redis settings.

在spec 节中，将 Dapr 配置为使用 Redis 缓存进行状态管理。spec节还包含组件特定的元数据。在这种情况下，可以使用它来配置其他 Redis 设置。

At a later time, the application is ready to go to production. For the production environment, you may want to change your state management to Azure Table Storage. Azure Table Storage provides state management capabilities that are affordable and highly durable.

稍后，应用程序已准备就绪，可以开始生产。对于生产环境，可能需要将状态管理替换为Azure Table Storage。Azure Table Storage提供经济实惠且经久耐用的状态管理功能。

At the time of this writing, the following component types are provided by Dapr:

撰写本文时，Dapr 提供以下组件类型：

TABLE 2
Component	Description
Service discovery	Used by the service invocation building block to integrate with the hosting environment to provide service-to-service discovery.
State	Provides a uniform interface to interact with a wide variety of state store implementations.
Pub/sub	Provides a uniform interface to interact with a wide variety of message bus implementations.
Bindings	Provides a uniform interface to trigger application events from external systems and invoke external systems with optional data payloads.
Middleware	Allows custom middleware to plug into the request processing pipeline and invoke additional actions on a request or response.
Secret stores	Provides a uniform interface to interact with external secret stores, including cloud, edge, commercial, open-source services.

表 2
组件	说明
服务发现	由服务调用构建块使用，用于与宿主环境集成以提供服务到服务发现。
状态	提供统一的接口以与各种状态存储实现交互。
发布/订阅	提供一个统一接口，用于与各种消息总线实现进行交互。
绑定	提供一个统一接口，用于从外部系统触发应用程序事件，并调用外部系统（随附可选数据负载）。
中间件	允许自定义中间件插入请求处理管道，并针对请求或响应调用其他操作。
机密存储	提供一个统一接口，用于与外部机密存储（包括云、边缘、商业、开源服务）交互。