caddy/plugins.go at master · forging2012/caddy · GitHub

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package caddy

import (

"fmt"

"log"

"net"

"sort"

"github.com/mholt/caddy/caddyfile"

)

// 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 = make(map[string]EventHook)

// 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 {

str := "Server types:\n"

for name := range serverTypes {

str += " " + name + "\n"

}

// List the loaders in registration order

str += "\nCaddyfile loaders:\n"

for _, loader := range caddyfileLoaders {

str += " " + loader.name + "\n"

}

if defaultCaddyfileLoader.name != "" {

str += " " + defaultCaddyfileLoader.name + "\n"

}

if len(eventHooks) > 0 {

// List the event hook plugins

str += "\nEvent hook plugins:\n"

for hookPlugin := range eventHooks {

str += " hook." + hookPlugin + "\n"

}

// Let's alphabetize the rest of these...

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)

}

sort.Strings(others)

str += "\nOther plugins:\n"

for _, name := range others {

str += " " + name + "\n"

}

return str

}

// 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() 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 the event names for the startup and shutdown events

const (

StartupEvent EventName = "startup"

ShutdownEvent EventName = "shutdown"

)

// 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")

}

if _, dup := eventHooks[name]; dup {

panic("hook named " + name + " already registered")

}

eventHooks[name] = hook

}

// 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{}) {

for name, hook := range eventHooks {

err := hook(event, info)

if err != nil {

log.Printf("error on '%s' hook: %v", name, err)

}

// 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", l.name, err)

}

if cdyfile != nil {

if caddyfileToUse != nil {

return nil, fmt.Errorf("Caddyfile loaded multiple times; first by %s, then by %s", loadedBy, l.name)

}

loaderUsed = l

caddyfileToUse = cdyfile

loadedBy = l.name

}

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

}

// 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)

)

caddy/plugins.go at master · forging2012/caddy · GitHub

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