spring-cloud-tencent/spring-cloud-tencent-examples/metadata-transfer-example

Spring Cloud Tencent Metadata Transfer example

Example Introduction

This example shows how to use spring-cloud-starter-tencent-metadata-transfer in Spring Cloud project for its features.

This example contains metadata-frontend、metadata-middle、metadata-backend.

Instruction

Configuration

The configuration is as the following shows. {ip} and {port} are Polaris backend IP address and port number.

spring:
  application:
    name: ${application.name}
  cloud:
    polaris:
      address: ${ip}:${port}

Maven Dependency

<dependency>
    <groupId>com.tencent.cloud</groupId>
    <artifactId>spring-cloud-starter-tencent-metadata-transfer</artifactId>
</dependency>

Launching Example

Launching Polaris Backend Service

Reference to Polaris Getting Started

Launching Application

• IDEA Launching

• spring-cloud-tencent-examples/metadata-transfer-example/metadata-frontend's MetadataFrontendService

• spring-cloud-tencent-examples/metadata-transfer-example/metadata-middle's MetadataMiddleService

• spring-cloud-tencent-examples/metadata-transfer-example/metadata-backend's MetadataBackendService

• Maven Package Launching

Execute under spring-cloud-tencent-examples/metadata-transfer-example

mvn clean package

Then find the jars under metadata-frontend、metadata-middle、metadata-backend, and run it:

java -jar ${app.jar}

Launch application, change ${app.jar} to jar's package name.

Metadata Configuration

• In the bootstrap.yml configuration file of the spring-cloud-tencent-examples/metadata-transfer-example/metadata-frontend project

spring:
  cloud:
    tencent:
      metadata:
        # Defined your metadata keys & values
        content:
          # Example: intransitive
          CUSTOM-METADATA-KEY-LOCAL: CUSTOM-VALUE-LOCAL
          # Example: transitive
          CUSTOM-METADATA-KEY-TRANSITIVE: CUSTOM-VALUE-TRANSITIVE
          # Example: disposable
          CUSTOM-METADATA-KEY-DISPOSABLE: CUSTOM-VALUE-DISPOSABLE-FRONTEND
        # Assigned which metadata key-value will be passed along the link
        transitive:
          - CUSTOM-METADATA-KEY-TRANSITIVE
        # Specify which metadata key value will be passed only once (one-step)
        disposable:
          - CUSTOM-METADATA-KEY-DISPOSABLE

• In the bootstrap.yml configuration file of the spring-cloud-tencent-examples/metadata-transfer-example/metadata-middle project

spring:
  cloud:
    tencent:
      metadata:
        # Defined your metadata keys & values
        content:
          # Example: intransitive
          CUSTOM-METADATA-KEY-LOCAL-2: CUSTOM-VALUE-LOCAL-2
          # Example: transitive
          CUSTOM-METADATA-KEY-TRANSITIVE-2: CUSTOM-VALUE-TRANSITIVE-2
          # Example: disposable
          CUSTOM-METADATA-KEY-DISPOSABLE: CUSTOM-VALUE-DISPOSABLE-MIDDLE
        # Assigned which metadata key-value will be passed along the link
        transitive:
          - CUSTOM-METADATA-KEY-TRANSITIVE-2
        # Specify which metadata key value will be passed only once (one-step)
        disposable:
          - CUSTOM-METADATA-KEY-DISPOSABLE

Verify

Request Invoke

curl -L -X GET 'http://127.0.0.1:48080/metadata/service/caller/feign/info'

Expected return rate

{
  "frontend-transitive-metadata": {
    "CUSTOM-METADATA-KEY-TRANSITIVE": "CUSTOM-VALUE-TRANSITIVE"
  },
  "frontend-upstream-disposable-metadata": {
  },
  "frontend-local-disposable-metadata": {
    "CUSTOM-METADATA-KEY-DISPOSABLE": "CUSTOM-VALUE-DISPOSABLE-FRONTEND"
  },
  
  "middle-transitive-metadata": {
    "CUSTOM-METADATA-KEY-TRANSITIVE": "CUSTOM-VALUE-TRANSITIVE",
    "CUSTOM-METADATA-KEY-TRANSITIVE-2": "CUSTOM-VALUE-TRANSITIVE-2"
  },
  "middle-upstream-disposable-metadata": {
    "CUSTOM-METADATA-KEY-DISPOSABLE": "CUSTOM-VALUE-DISPOSABLE-FRONTEND"
  },
  "middle-local-disposable-metadata": {
    "CUSTOM-METADATA-KEY-DISPOSABLE": "CUSTOM-VALUE-DISPOSABLE-MIDDLE"
  },
  
  "backend-transitive-metadata": {
    "CUSTOM-METADATA-KEY-TRANSITIVE": "CUSTOM-VALUE-TRANSITIVE",
    "CUSTOM-METADATA-KEY-TRANSITIVE-2": "CUSTOM-VALUE-TRANSITIVE-2"
  },
  "backend-upstream-disposable-metadata": {
    "CUSTOM-METADATA-KEY-DISPOSABLE": "CUSTOM-VALUE-DISPOSABLE-MIDDLE"
  },
  "backend-local-disposable-metadata": {
  }
}

Response value description

* (asterisk), representing frontend, middle, backend in the example.

• Key *-transitive-metadata represents all the passable (fully linked) metadata configured by default in the service.
• Key *-upstream-disposable-metadata indicates the one-time transmissible metadata obtained from upstream requests in the service.
• Key *-local-disposable-metadata indicates the one-time metadata passed downstream as configured by the current service.

How to get the passed metadata via Api

• Get the metadata passed globally

MetadataContext context = MetadataContextHolder.get();
        Map<String, String> customMetadataMap = context.getFragmentContext(MetadataContext.FRAGMENT_TRANSITIVE);

customMetadataMap.forEach((key, value) -> {
    // ...
});

• Get disposable(one-time) metadata passed from upstream

Map<String, String> upstreamDisposableMetadatas = MetadataContextHolder.getAllDisposableMetadata(true);
upstreamDisposableMetadatas.forEach((key, value) -> {
    // ...
});

• Get disposable(one-time) metadata for local configuration

Map<String, String> localDisposableMetadatas = MetadataContextHolder.getAllDisposableMetadata(false);
localDisposableMetadatas.forEach((key, value) -> {
    // ...
});

Wiki Reference

See Spring Cloud Tencent Metadata Transfer Usage Document for more reference .