Tanzu Hub Client

This package enables the creation of authenticated Tanzu Hub clients which in turn enables the interaction with Tanzu Hub endpoint through GraphQL queries for the tanzu context.

Note: The Tanzu Hub Client feature is an EXPERIMENTAL feature. The API signature and implementation are subjected to change/removal if an alternative means to provide equivalent functionality can be introduced.

Creating a Tanzu Hub Client

To create a Tanzu Hub client, use the NewClient(contextName string) API by providing the tanzu context name. An authenticated Tanzu Hub client for the specified tanzu context will be returned. Internally it configures the client with an access token for each request. By default, it will get the Tanzu Hub endpoint from the specified context metadata. To specify any custom Tanzu Hub endpoint for testing please configure the TANZU_HUB_ENDPOINT environment variable.

Note that the authenticated client is assured to have at least 30 min access to the GraphQL endpoint. If you want a long running client beyond this period, recommendation is to reinitialize your client.

Examples

Query/Mutation

const QueryAllProjects_Operation = `
query QueryAllProjects {
    applicationEngineQuery {
        queryProjects(first: 1000) {
            projects {
                name
            }
        }
    }
}`

// getProjects is a wrapper of an `QueryAllProjects“ API call to fetch project names
func getProjects(contextName string) ([]string, error) {
    hc, err := NewClient(contextName )

    req := &hub.Request{
        OpName: "QueryAllProjects",
        Query:  QueryAllProjects_Operation,
    }
    var responseData QueryAllProjectsResponse // Assuming the response type is already defined
    err := hc.Request(context.Background(), req, &responseData)
    if err != nil {
        return nil, err
    }

    // Process the response
    projects := []string{}
    for _, p := range responseData.ApplicationEngineQuery.QueryProjects.Projects {
        projects = append(projects, p.Name)
    }

    return projects, nil
}

Subscriptions

const SubscribeAppLogs_Operation = `
subscription appLogs($appEntityId: EntityId!) {
  kubernetesAppLogs(appEntityId: $appEntityId, logParams: {includeTimestamps: true, tailLines: 50, includePrevious: false}) {
    value
    timestamp
  }
}`

func subscribeAppLogs(contextName, appEntityId string) ([]string, error) {
    hc, err := NewClient(contextName )

    req := &hub.Request{
        OpName: "SubscribeAppLogs",
        Query:  SubscribeAppLogs_Operation,
        Variables: map[string]string{"appEntityId": appEntityId}
    }

    err := hc.Subscribe(context.Background(), req, logEventHandler)
    if err != nil {
        return nil, err
    }

    return nil
}

func logEventHandler(eventResponse EventResponse) {
    rawData := eventResponse.RawData
    responseData := eventResponse.ResponseData
    fmt.Println(string(rawData))
    fmt.Println(responseData)
}

Generating the golang stub for the GraphQL queries

There are many golang client libraries for the GraphQL, however, Tanzu Plugin Runtime recommends using github.com/Khan/genqlient for generating type definitions for your GraphQL queries.

Note: Client does not require users to use this library for generating type definitions and users can always define the Golang type definitions for the specified query by themselves.