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// Copyright 2015 Light Code Labs, LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package caddy
import (
// These are all the registered plugins.
var (
// serverTypes is a map of registered server types.
serverTypes = make(map[string]ServerType)
// plugins is a map of server type to map of plugin name to
// Plugin. These are the "general" plugins that may or may
// not be associated with a specific server type. If it's
// applicable to multiple server types or the server type is
// irrelevant, the key is empty string (""). But all plugins
// must have a name.
plugins = make(map[string]map[string]Plugin)
// eventHooks is a map of hook name to Hook. All hooks plugins
// must have a name.
eventHooks = &sync.Map{}
// parsingCallbacks maps server type to map of directive
// to list of callback functions. These aren't really
// plugins on their own, but are often registered from
// plugins.
parsingCallbacks = make(map[string]map[string][]ParsingCallback)
// caddyfileLoaders is the list of all Caddyfile loaders
// in registration order.
caddyfileLoaders []caddyfileLoader
// DescribePlugins returns a string describing the registered plugins.
func DescribePlugins() string {
pl := ListPlugins()
str := "Server types:\n"
for _, name := range pl["server_types"] {
str += " " + name + "\n"
str += "\nCaddyfile loaders:\n"
for _, name := range pl["caddyfile_loaders"] {
str += " " + name + "\n"
if len(pl["event_hooks"]) > 0 {
str += "\nEvent hook plugins:\n"
for _, name := range pl["event_hooks"] {
str += " hook." + name + "\n"
if len(pl["clustering"]) > 0 {
str += "\nClustering plugins:\n"
for _, name := range pl["clustering"] {
str += " " + name + "\n"
str += "\nOther plugins:\n"
for _, name := range pl["others"] {
str += " " + name + "\n"
return str
// ListPlugins makes a list of the registered plugins,
// keyed by plugin type.
func ListPlugins() map[string][]string {
p := make(map[string][]string)
// server type plugins
for name := range serverTypes {
p["server_types"] = append(p["server_types"], name)
// caddyfile loaders in registration order
for _, loader := range caddyfileLoaders {
p["caddyfile_loaders"] = append(p["caddyfile_loaders"],
if != "" {
p["caddyfile_loaders"] = append(p["caddyfile_loaders"],
// List the event hook plugins
eventHooks.Range(func(k, _ interface{}) bool {
p["event_hooks"] = append(p["event_hooks"], k.(string))
return true
// alphabetize the rest of the plugins
var others []string
for stype, stypePlugins := range plugins {
for name := range stypePlugins {
var s string
if stype != "" {
s = stype + "."
s += name
others = append(others, s)
for _, name := range others {
p["others"] = append(p["others"], name)
return p
// ValidDirectives returns the list of all directives that are
// recognized for the server type serverType. However, not all
// directives may be installed. This makes it possible to give
// more helpful error messages, like "did you mean ..." or
// "maybe you need to plug in ...".
func ValidDirectives(serverType string) []string {
stype, err := getServerType(serverType)
if err != nil {
return nil
return stype.Directives()
// ServerListener pairs a server to its listener and/or packetconn.
type ServerListener struct {
server Server
listener net.Listener
packet net.PacketConn
// LocalAddr returns the local network address of the packetconn. It returns
// nil when it is not set.
func (s ServerListener) LocalAddr() net.Addr {
if s.packet == nil {
return nil
return s.packet.LocalAddr()
// Addr returns the listener's network address. It returns nil when it is
// not set.
func (s ServerListener) Addr() net.Addr {
if s.listener == nil {
return nil
return s.listener.Addr()
// Context is a type which carries a server type through
// the load and setup phase; it maintains the state
// between loading the Caddyfile, then executing its
// directives, then making the servers for Caddy to
// manage. Typically, such state involves configuration
// structs, etc.
type Context interface {
// Called after the Caddyfile is parsed into server
// blocks but before the directives are executed,
// this method gives you an opportunity to inspect
// the server blocks and prepare for the execution
// of directives. Return the server blocks (which
// you may modify, if desired) and an error, if any.
// The first argument is the name or path to the
// configuration file (Caddyfile).
// This function can be a no-op and simply return its
// input if there is nothing to do here.
InspectServerBlocks(string, []caddyfile.ServerBlock) ([]caddyfile.ServerBlock, error)
// This is what Caddy calls to make server instances.
// By this time, all directives have been executed and,
// presumably, the context has enough state to produce
// server instances for Caddy to start.
MakeServers() ([]Server, error)
// RegisterServerType registers a server type srv by its
// name, typeName.
func RegisterServerType(typeName string, srv ServerType) {
if _, ok := serverTypes[typeName]; ok {
panic("server type already registered")
serverTypes[typeName] = srv
// ServerType contains information about a server type.
type ServerType struct {
// Function that returns the list of directives, in
// execution order, that are valid for this server
// type. Directives should be one word if possible
// and lower-cased.
Directives func() []string
// DefaultInput returns a default config input if none
// is otherwise loaded. This is optional, but highly
// recommended, otherwise a blank Caddyfile will be
// used.
DefaultInput func() Input
// The function that produces a new server type context.
// This will be called when a new Caddyfile is being
// loaded, parsed, and executed independently of any
// startup phases before this one. It's a way to keep
// each set of server instances separate and to reduce
// the amount of global state you need.
NewContext func(inst *Instance) Context
// Plugin is a type which holds information about a plugin.
type Plugin struct {
// ServerType is the type of server this plugin is for.
// Can be empty if not applicable, or if the plugin
// can associate with any server type.
ServerType string
// Action is the plugin's setup function, if associated
// with a directive in the Caddyfile.
Action SetupFunc
// RegisterPlugin plugs in plugin. All plugins should register
// themselves, even if they do not perform an action associated
// with a directive. It is important for the process to know
// which plugins are available.
// The plugin MUST have a name: lower case and one word.
// If this plugin has an action, it must be the name of
// the directive that invokes it. A name is always required
// and must be unique for the server type.
func RegisterPlugin(name string, plugin Plugin) {
if name == "" {
panic("plugin must have a name")
if _, ok := plugins[plugin.ServerType]; !ok {
plugins[plugin.ServerType] = make(map[string]Plugin)
if _, dup := plugins[plugin.ServerType][name]; dup {
panic("plugin named " + name + " already registered for server type " + plugin.ServerType)
plugins[plugin.ServerType][name] = plugin
// EventName represents the name of an event used with event hooks.
type EventName string
// Define names for the various events
const (
StartupEvent EventName = "startup"
ShutdownEvent = "shutdown"
CertRenewEvent = "certrenew"
InstanceStartupEvent = "instancestartup"
InstanceRestartEvent = "instancerestart"
// EventHook is a type which holds information about a startup hook plugin.
type EventHook func(eventType EventName, eventInfo interface{}) error
// RegisterEventHook plugs in hook. All the hooks should register themselves
// and they must have a name.
func RegisterEventHook(name string, hook EventHook) {
if name == "" {
panic("event hook must have a name")
_, dup := eventHooks.LoadOrStore(name, hook)
if dup {
panic("hook named " + name + " already registered")
// EmitEvent executes the different hooks passing the EventType as an
// argument. This is a blocking function. Hook developers should
// use 'go' keyword if they don't want to block Caddy.
func EmitEvent(event EventName, info interface{}) {
eventHooks.Range(func(k, v interface{}) bool {
err := v.(EventHook)(event, info)
if err != nil {
log.Printf("error on '%s' hook: %v", k.(string), err)
return true
// cloneEventHooks return a clone of the event hooks *sync.Map
func cloneEventHooks() *sync.Map {
c := &sync.Map{}
eventHooks.Range(func(k, v interface{}) bool {
c.Store(k, v)
return true
return c
// purgeEventHooks purges all event hooks from the map
func purgeEventHooks() {
eventHooks.Range(func(k, _ interface{}) bool {
return true
// restoreEventHooks restores eventHooks with a provided *sync.Map
func restoreEventHooks(m *sync.Map) {
// Purge old event hooks
// Restore event hooks
m.Range(func(k, v interface{}) bool {
eventHooks.Store(k, v)
return true
// ParsingCallback is a function that is called after
// a directive's setup functions have been executed
// for all the server blocks.
type ParsingCallback func(Context) error
// RegisterParsingCallback registers callback to be called after
// executing the directive afterDir for server type serverType.
func RegisterParsingCallback(serverType, afterDir string, callback ParsingCallback) {
if _, ok := parsingCallbacks[serverType]; !ok {
parsingCallbacks[serverType] = make(map[string][]ParsingCallback)
parsingCallbacks[serverType][afterDir] = append(parsingCallbacks[serverType][afterDir], callback)
// SetupFunc is used to set up a plugin, or in other words,
// execute a directive. It will be called once per key for
// each server block it appears in.
type SetupFunc func(c *Controller) error
// DirectiveAction gets the action for directive dir of
// server type serverType.
func DirectiveAction(serverType, dir string) (SetupFunc, error) {
if stypePlugins, ok := plugins[serverType]; ok {
if plugin, ok := stypePlugins[dir]; ok {
return plugin.Action, nil
if genericPlugins, ok := plugins[""]; ok {
if plugin, ok := genericPlugins[dir]; ok {
return plugin.Action, nil
return nil, fmt.Errorf("no action found for directive '%s' with server type '%s' (missing a plugin?)",
dir, serverType)
// Loader is a type that can load a Caddyfile.
// It is passed the name of the server type.
// It returns an error only if something went
// wrong, not simply if there is no Caddyfile
// for this loader to load.
// A Loader should only load the Caddyfile if
// a certain condition or requirement is met,
// as returning a non-nil Input value along with
// another Loader will result in an error.
// In other words, loading the Caddyfile must
// be deliberate & deterministic, not haphazard.
// The exception is the default Caddyfile loader,
// which will be called only if no other Caddyfile
// loaders return a non-nil Input. The default
// loader may always return an Input value.
type Loader interface {
Load(serverType string) (Input, error)
// LoaderFunc is a convenience type similar to http.HandlerFunc
// that allows you to use a plain function as a Load() method.
type LoaderFunc func(serverType string) (Input, error)
// Load loads a Caddyfile.
func (lf LoaderFunc) Load(serverType string) (Input, error) {
return lf(serverType)
// RegisterCaddyfileLoader registers loader named name.
func RegisterCaddyfileLoader(name string, loader Loader) {
caddyfileLoaders = append(caddyfileLoaders, caddyfileLoader{name: name, loader: loader})
// SetDefaultCaddyfileLoader registers loader by name
// as the default Caddyfile loader if no others produce
// a Caddyfile. If another Caddyfile loader has already
// been set as the default, this replaces it.
// Do not call RegisterCaddyfileLoader on the same
// loader; that would be redundant.
func SetDefaultCaddyfileLoader(name string, loader Loader) {
defaultCaddyfileLoader = caddyfileLoader{name: name, loader: loader}
// loadCaddyfileInput iterates the registered Caddyfile loaders
// and, if needed, calls the default loader, to load a Caddyfile.
// It is an error if any of the loaders return an error or if
// more than one loader returns a Caddyfile.
func loadCaddyfileInput(serverType string) (Input, error) {
var loadedBy string
var caddyfileToUse Input
for _, l := range caddyfileLoaders {
cdyfile, err := l.loader.Load(serverType)
if err != nil {
return nil, fmt.Errorf("loading Caddyfile via %s: %v",, err)
if cdyfile != nil {
if caddyfileToUse != nil {
return nil, fmt.Errorf("Caddyfile loaded multiple times; first by %s, then by %s", loadedBy,
loaderUsed = l
caddyfileToUse = cdyfile
loadedBy =
if caddyfileToUse == nil && defaultCaddyfileLoader.loader != nil {
cdyfile, err := defaultCaddyfileLoader.loader.Load(serverType)
if err != nil {
return nil, err
if cdyfile != nil {
loaderUsed = defaultCaddyfileLoader
caddyfileToUse = cdyfile
return caddyfileToUse, nil
// OnProcessExit is a list of functions to run when the process
// exits -- they are ONLY for cleanup and should not block,
// return errors, or do anything fancy. They will be run with
// every signal, even if "shutdown callbacks" are not executed.
// This variable must only be modified in the main goroutine
// from init() functions.
var OnProcessExit []func()
// caddyfileLoader pairs the name of a loader to the loader.
type caddyfileLoader struct {
name string
loader Loader
var (
defaultCaddyfileLoader caddyfileLoader // the default loader if all else fail
loaderUsed caddyfileLoader // the loader that was used (relevant for reloads)
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