support custom server options when constructing handlers

[zaquestion]

useful when implemention your own main.go

[toctan]

@zaquestion I was wondering if it's possible to make it a little bit easier to provide custom server options without writing a new main.go, since a lot of packages in go-kit require some of these server options, for example, jwt and zipkin tracing. Can we provide a function similar to handlers.WrapEndpoints and handlers.WrapService so that the user could easily inject custom server options into svc/server/run.go? Maybe something like handlers.CustomServerOptions, or we could put it into another package like transport? This should be pretty easy to implement. I could send out a pull request if you think this is a good idea, thanks!

[zaquestion]

Generally we recommend creating your own main.go since it's pretty straightforward and expands the control available to users who want more custom options. Historically, we haven't seen this as a pain point, and it helps keep "default truss" as transport agnostic as possible. I would certainly entertain a PR or discussion in a new Issue, one thing I'll say here is that there are custom server options that can be passed to grpc and/or http/json handlers, so we'd likely want ways to configure them individually, which could get messy down the line as additional transports are added.

Ref: https://github.com/metaverse/truss/wiki/Using-a-custom-main.go-with-generated-truss-services

For what it's worth, I use custom main.go files in many of my personal/work projects, particularly when I want to use truss http only.

[toctan]

Got it. I didn't know it was recommended to create my own main.go, but it definitely works for my use case. Thanks!

I also realized that we need to have different server options for different transports, so I was thinking something like this:

// InjectGRPCServerOptions provides a list of server options to grpctransport.NewServer.
func InjectGRPCServerOptions() []grpctransport.ServerOption {
    options := []grpctransport.ServerOption{
        grpctransport.ServerBefore(jwt.GRPCToContext()),
    }
    return options
}

// InjectHTTPServerOptions provides a list of server options to httptransport.NewServer.
func InjectHTTPServerOptions() []httptransport.ServerOption {
    options := []httptransport.ServerOption{
        httptransport.ServerBefore(jwt.HTTPToContext()),
    }
    return options
}