Add a support channel¶

When your tool fails in someone else's hands, the most useful thing you can add is where to get help. HelpConfig appends a support message to every reported error.

Implement the interface¶

The module ships the interface and no implementations, because it has no opinion about where your team's support channel lives:

type HelpConfig interface {
    SupportMessage() string
}

So write the one that matches your organisation:

type slackHelp struct {
    Team    string
    Channel string
}

func (s slackHelp) SupportMessage() string {
    if s.Team == "" || s.Channel == "" {
        return "" // not configured: stay silent
    }

    return fmt.Sprintf("For assistance, contact %s via Slack channel %s", s.Team, s.Channel)
}

Pass it when constructing the handler:

handler := errorhandling.New(logger, slackHelp{Team: "Platform", Channel: "#support"})

Every reported error now carries a help field:

level=ERROR msg="deploy failed" err.msg="deploy failed" err.kind=errors.basic err.hint="[Check your cluster credentials]" help="For assistance, contact Platform via Slack channel #support"

Returning an empty string suppresses it¶

An implementation that returns "" adds nothing to the output. That is the designed way to stay quiet when a channel isn't configured yet, with no nil juggling and no half-rendered "contact via " messages.

Passing nil for the whole HelpConfig disables help output entirely:

handler := errorhandling.New(logger, nil)

Anything can be a help channel¶

Because it's a one-method interface, the message can come from anywhere: a wiki URL, an on-call rota looked up at startup, a value read from configuration:

type configuredHelp struct{ msg string }

func (c configuredHelp) SupportMessage() string { return c.msg }

handler := errorhandling.New(logger, configuredHelp{
    msg: cfg.GetString("support.message"),
})

Keep it cheap: SupportMessage is called on every reported error, so it should not do I/O. Resolve the value once at startup and hold it. It is called on the reporting goroutine with no context and no cancellation, so it must not block and must be safe to call concurrently.

Which reports get the help message¶

All of them. The message is attached to every report at every level, including reports of this module's own sentinels, whatever the outcome says. The only ways to get no help field are a nil HelpConfig or a SupportMessage that returns "".

The message also cannot vary by error: one HelpConfig serves the whole handler, and SupportMessage() is called with no argument. If different failures need different channels, put the routing in a hint instead.

Why the module ships no implementations¶

A Slack or Teams struct is an opinion about which vendor you use and about the config shape that populates it. Baking either into the module would make every consumer carry someone else's choice. The interface is the extension point; the implementation is yours, exactly as it should be.