Dial a service with middleware¶

grpcclient.Dial builds the connection and selects credentials; the per-call behaviour — circuit breaking, OpenTelemetry — comes from go/transit's gRPC client interceptors, which you pass to Dial as ordinary grpc.DialOptions.

import (
    "gitlab.com/phpboyscout/go/grpcclient"
    transitgrpc "gitlab.com/phpboyscout/go/transit/grpc"
    "google.golang.org/grpc"
)

The client-side interceptors¶

go/transit/grpc exposes three client-side helpers:

(Request logging is a server-side interceptor in transit — there is no client logging interceptor.)

A full client stack¶

cfg := transitgrpc.DefaultCircuitBreakerConfig()

conn, err := grpcclient.Dial(
    grpcclient.Target{Host: "svc.internal", Port: 443, TLS: pair},

    // circuit breaking on both unary and streaming calls
    grpc.WithChainUnaryInterceptor(transitgrpc.CircuitBreakerInterceptor(log, cfg)),
    grpc.WithChainStreamInterceptor(transitgrpc.CircuitBreakerStreamInterceptor(log, cfg)),

    // OpenTelemetry client instrumentation
    transitgrpc.OTelClientHandler(),
)
if err != nil {
    return err
}
defer conn.Close()

Because Dial appends your options after the transport credentials it sets from Target.TLS, the credentials always win — a caller cannot accidentally weaken the target's transport security through an option.

Credentials come from the Target¶

You never pass grpc.WithTransportCredentials yourself: Dial derives it from Target.TLS. Set TLS.Enabled and (optionally) TLS.Cert to control it — see The Target model & credentials.

Bring your own dial options¶

Any grpc.DialOption is accepted — keepalive, message-size limits, a custom resolver, a service-config — and applied on top of the credentials Dial sets:

conn, err := grpcclient.Dial(
    grpcclient.Target{Port: 8080},
    grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(16<<20)),
)