mesh-sdk/go/catalogue/busy.go

package catalogue

import (
	"fmt"
	"sort"
	"strings"
	"time"
)

// BusyField is the resource field.
const BusyField = "busy"

// The bounds of one ask (ADR 0335), the node-engine's own, held here near the author.
const (
	BusyTimeoutDefault = 10 * time.Second
	BusyTimeoutCeiling = time.Minute
)

// Busy is one container's busy, read.
type Busy struct {
	Command string
	Timeout time.Duration
}

// ReadBusy reads a resource's `busy` field, its default applied. False when it carries none.
func ReadBusy(r map[string]any) (Busy, bool, []string) {
	raw, present := r[BusyField]
	if !present {
		return Busy{}, false, nil
	}
	id := fmt.Sprint(r["id"])
	fields, ok := raw.(map[string]any)
	if !ok {
		return Busy{}, true, []string{fmt.Sprintf("%s: busy is %T; it is an object with a command", id, raw)}
	}
	var problems []string
	keys := make([]string, 0, len(fields))
	for k := range fields {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for _, k := range keys {
		if k != "command" && k != "timeout" {
			problems = append(problems, fmt.Sprintf("%s: its busy says %q; busy has a command and a timeout", id, k))
		}
	}
	b := Busy{Timeout: BusyTimeoutDefault}
	if v, has := fields["command"]; has {
		s, ok := v.(string)
		if !ok {
			problems = append(problems, fmt.Sprintf("%s: its busy's command is %T; it is text", id, v))
		}
		b.Command = strings.TrimSpace(s)
	}
	if v, has := fields["timeout"]; has {
		s, _ := v.(string)
		d, err := time.ParseDuration(strings.TrimSpace(s))
		switch {
		case err != nil:
			problems = append(problems, fmt.Sprintf("%s: its busy's timeout is %v; it is a duration such as \"10s\"", id, v))
		case d <= 0 || d > BusyTimeoutCeiling:
			problems = append(problems, fmt.Sprintf("%s: an ask of its busy takes more than nothing and at most %s, not %s",
				id, BusyTimeoutCeiling, d))
		default:
			b.Timeout = d
		}
	}
	return b, true, problems
}