cadence go-client/ client to reach server for fetching workflow results in panic

Question

First time user of Cadence:

Scenario I have a cadence server running in my sandbox environment. Intent is to fetch the workflow status

I am trying to use this cadence client

go.uber.org/cadence/client

on my local host to talk to my sandbox cadence server.

This is my simple code snippet:

var cadClient client.Client

func main() {
wfID := "01ERMTDZHBYCH4GECHB3J692PC" << I got this from cadence-ui
ctx := context.Background()
wf := cadClientlient.GetWorkflow(ctx, wfID,"") <<< Panic hits here
log.Println("Workflow RunID: ",wf.GetID())
}

I am sure getting it wrong because the client does not know how to reach the cadence server. I referred this https://cadenceworkflow.io/docs/go-client/ to find the correct usage but could not find any reference (possible that I might have missed it).

Any help in how to resolve/implement this, will be of much help

Answer 1

I am not sure what panic you got. Based on the code snippet, it's likely that you haven't initialized the client.

To initialize it, follow the sample code here: https://github.com/uber-common/cadence-samples/blob/master/cmd/samples/common/sample_helper.go#L82

and

https://github.com/uber-common/cadence-samples/blob/aac75c7ca03ec0c184d0f668c8cd0ea13d3a7aa4/cmd/samples/common/factory.go#L113

    ch, err := tchannel.NewChannelTransport(
        tchannel.ServiceName(_cadenceClientName))
    if err != nil {
        b.Logger.Fatal("Failed to create transport channel", zap.Error(err))
    }

    b.Logger.Debug("Creating RPC dispatcher outbound",
        zap.String("ServiceName", _cadenceFrontendService),
        zap.String("HostPort", b.hostPort))

    b.dispatcher = yarpc.NewDispatcher(yarpc.Config{
        Name: _cadenceClientName,
        Outbounds: yarpc.Outbounds{
            _cadenceFrontendService: {Unary: ch.NewSingleOutbound(b.hostPort)},
        },
    })

    if b.dispatcher != nil {
        if err := b.dispatcher.Start(); err != nil {
            b.Logger.Fatal("Failed to create outbound transport channel: %v", zap.Error(err))
        

    client := workflowserviceclient.New(b.dispatcher.ClientConfig(_cadenceFrontendService))