/
middleware.go
95 lines (73 loc) · 1.5 KB
/
middleware.go
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package middleware
import (
"errors"
"sync"
"github.com/semihalev/log"
"github.com/semihalev/sdns/config"
"github.com/semihalev/sdns/ctx"
)
type middleware struct {
mu sync.RWMutex
cfg *config.Config
handlers []handler
}
type handler struct {
name string
new func(*config.Config) ctx.Handler
}
var (
ctxHandlers []ctx.Handler
setup bool
m middleware
)
// Register a middleware
func Register(name string, new func(*config.Config) ctx.Handler) {
log.Info("Register middleware", "name", name, "index", len(m.handlers))
m.mu.Lock()
defer m.mu.Unlock()
m.handlers = append(m.handlers, handler{name: name, new: new})
}
// Setup handlers
func Setup(cfg *config.Config) error {
if setup {
return errors.New("setup already done")
}
m.cfg = cfg
m.mu.RLock()
defer m.mu.RUnlock()
for _, handler := range m.handlers {
ctxHandlers = append(ctxHandlers, handler.new(m.cfg))
}
setup = true
return nil
}
// Handlers return registered handlers
func Handlers() []ctx.Handler {
return ctxHandlers
}
// List return names of handlers
func List() (list []string) {
m.mu.RLock()
defer m.mu.RUnlock()
for _, handler := range m.handlers {
list = append(list, handler.name)
}
return list
}
// Get return a handler by name
func Get(name string) ctx.Handler {
if !setup {
return nil
}
m.mu.RLock()
defer m.mu.RUnlock()
for i, handler := range m.handlers {
if handler.name == name {
if len(ctxHandlers) <= i {
return nil
}
return ctxHandlers[i]
}
}
return nil
}