fork of 🔒 because I wanted simpler TLS on the admin API listener
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// Copyright 2015 Matthew Holt and The Caddy Authors
// 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 (
// Module is a type that is used as a Caddy module. In
// addition to this interface, most modules will implement
// some interface expected by their host module in order
// to be useful. To learn which interface(s) to implement,
// see the documentation for the host module. At a bare
// minimum, this interface, when implemented, only provides
// the module's ID and constructor function.
// Modules will often implement additional interfaces
// including Provisioner, Validator, and CleanerUpper.
// If a module implements these interfaces, their
// methods are called during the module's lifespan.
// When a module is loaded by a host module, the following
// happens: 1) ModuleInfo.New() is called to get a new
// instance of the module. 2) The module's configuration is
// unmarshaled into that instance. 3) If the module is a
// Provisioner, the Provision() method is called. 4) If the
// module is a Validator, the Validate() method is called.
// 5) The module will probably be type-asserted from
// interface{} to some other, more useful interface expected
// by the host module. For example, HTTP handler modules are
// type-asserted as caddyhttp.MiddlewareHandler values.
// 6) When a module's containing Context is canceled, if it is
// a CleanerUpper, its Cleanup() method is called.
type Module interface {
// This method indicates that the type is a Caddy
// module. The returned ModuleInfo must have both
// a name and a constructor function. This method
// must not have any side-effects.
CaddyModule() ModuleInfo
// ModuleInfo represents a registered Caddy module.
type ModuleInfo struct {
// ID is the "full name" of the module. It
// must be unique and properly namespaced.
ID ModuleID
// New returns a pointer to a new, empty
// instance of the module's type. This
// method must not have any side-effects,
// and no other initialization should
// occur within it. Any initialization
// of the returned value should be done
// in a Provision() method (see the
// Provisioner interface).
New func() Module
// ModuleID is a string that uniquely identifies a Caddy module. A
// module ID is lightly structured. It consists of dot-separated
// labels which form a simple hierarchy from left to right. The last
// label is the module name, and the labels before that constitute
// the namespace (or scope).
// Thus, a module ID has the form: <namespace>.<name>
// An ID with no dot has the empty namespace, which is appropriate
// for app modules (these are "top-level" modules that Caddy core
// loads and runs).
// Module IDs should be lowercase and use underscores (_) instead of
// spaces.
// Examples of valid IDs:
// - http
// - http.handlers.file_server
// - caddy.logging.encoders.json
type ModuleID string
// Namespace returns the namespace (or scope) portion of a module ID,
// which is all but the last label of the ID. If the ID has only one
// label, then the namespace is empty.
func (id ModuleID) Namespace() string {
lastDot := strings.LastIndex(string(id), ".")
if lastDot < 0 {
return ""
return string(id)[:lastDot]
// Name returns the Name (last element) of a module ID.
func (id ModuleID) Name() string {
if id == "" {
return ""
parts := strings.Split(string(id), ".")
return parts[len(parts)-1]
func (mi ModuleInfo) String() string { return string(mi.ID) }
// ModuleMap is a map that can contain multiple modules,
// where the map key is the module's name. (The namespace
// is usually read from an associated field's struct tag.)
// Because the module's name is given as the key in a
// module map, the name does not have to be given in the
// json.RawMessage.
type ModuleMap map[string]json.RawMessage
// RegisterModule registers a module by receiving a
// plain/empty value of the module. For registration to
// be properly recorded, this should be called in the
// init phase of runtime. Typically, the module package
// will do this as a side-effect of being imported.
// This function panics if the module's info is
// incomplete or invalid, or if the module is already
// registered.
func RegisterModule(instance Module) {
mod := instance.CaddyModule()
if mod.ID == "" {
panic("module ID missing")
if mod.ID == "caddy" || mod.ID == "admin" {
panic(fmt.Sprintf("module ID '%s' is reserved", mod.ID))
if mod.New == nil {
panic("missing ModuleInfo.New")
if val := mod.New(); val == nil {
panic("ModuleInfo.New must return a non-nil module instance")
defer modulesMu.Unlock()
if _, ok := modules[string(mod.ID)]; ok {
panic(fmt.Sprintf("module already registered: %s", mod.ID))
modules[string(mod.ID)] = mod
// GetModule returns module information from its ID (full name).
func GetModule(name string) (ModuleInfo, error) {
defer modulesMu.RUnlock()
m, ok := modules[name]
if !ok {
return ModuleInfo{}, fmt.Errorf("module not registered: %s", name)
return m, nil
// GetModuleName returns a module's name (the last label of its ID)
// from an instance of its value. If the value is not a module, an
// empty string will be returned.
func GetModuleName(instance interface{}) string {
var name string
if mod, ok := instance.(Module); ok {
name = mod.CaddyModule().ID.Name()
return name
// GetModuleID returns a module's ID from an instance of its value.
// If the value is not a module, an empty string will be returned.
func GetModuleID(instance interface{}) string {
var id string
if mod, ok := instance.(Module); ok {
id = string(mod.CaddyModule().ID)
return id
// GetModules returns all modules in the given scope/namespace.
// For example, a scope of "foo" returns modules named "",
// "foo.loo", but not "bar", "", etc. An empty scope
// returns top-level modules, for example "foo" or "bar". Partial
// scopes are not matched (i.e. scope "" does not match
// name "").
// Because modules are registered to a map under the hood, the
// returned slice will be sorted to keep it deterministic.
func GetModules(scope string) []ModuleInfo {
defer modulesMu.RUnlock()
scopeParts := strings.Split(scope, ".")
// handle the special case of an empty scope, which
// should match only the top-level modules
if scope == "" {
scopeParts = []string{}
var mods []ModuleInfo
for id, m := range modules {
modParts := strings.Split(id, ".")
// match only the next level of nesting
if len(modParts) != len(scopeParts)+1 {
// specified parts must be exact matches
for i := range scopeParts {
if modParts[i] != scopeParts[i] {
continue iterateModules
mods = append(mods, m)
// make return value deterministic
sort.Slice(mods, func(i, j int) bool {
return mods[i].ID < mods[j].ID
return mods
// Modules returns the names of all registered modules
// in ascending lexicographical order.
func Modules() []string {
defer modulesMu.RUnlock()
names := make([]string, 0, len(modules))
for name := range modules {
names = append(names, name)
return names
// getModuleNameInline loads the string value from raw of moduleNameKey,
// where raw must be a JSON encoding of a map. It returns that value,
// along with the result of removing that key from raw.
func getModuleNameInline(moduleNameKey string, raw json.RawMessage) (string, json.RawMessage, error) {
var tmp map[string]interface{}
err := json.Unmarshal(raw, &tmp)
if err != nil {
return "", nil, err
moduleName, ok := tmp[moduleNameKey].(string)
if !ok || moduleName == "" {
return "", nil, fmt.Errorf("module name not specified with key '%s' in %+v", moduleNameKey, tmp)
// remove key from the object, otherwise decoding it later
// will yield an error because the struct won't recognize it
// (this is only needed because we strictly enforce that
// all keys are recognized when loading modules)
delete(tmp, moduleNameKey)
result, err := json.Marshal(tmp)
if err != nil {
return "", nil, fmt.Errorf("re-encoding module configuration: %v", err)
return moduleName, result, nil
// Provisioner is implemented by modules which may need to perform
// some additional "setup" steps immediately after being loaded.
// Provisioning should be fast (imperceptible running time). If
// any side-effects result in the execution of this function (e.g.
// creating global state, any other allocations which require
// garbage collection, opening files, starting goroutines etc.),
// be sure to clean up properly by implementing the CleanerUpper
// interface to avoid leaking resources.
type Provisioner interface {
Provision(Context) error
// Validator is implemented by modules which can verify that their
// configurations are valid. This method will be called after
// Provision() (if implemented). Validation should always be fast
// (imperceptible running time) and an error must be returned if
// the module's configuration is invalid.
type Validator interface {
Validate() error
// CleanerUpper is implemented by modules which may have side-effects
// such as opened files, spawned goroutines, or allocated some sort
// of non-stack state when they were provisioned. This method should
// deallocate/cleanup those resources to prevent memory leaks. Cleanup
// should be fast and efficient. Cleanup should work even if Provision
// returns an error, to allow cleaning up from partial provisionings.
type CleanerUpper interface {
Cleanup() error
// ParseStructTag parses a caddy struct tag into its keys and values.
// It is very simple. The expected syntax is:
// `caddy:"key1=val1 key2=val2 ..."`
func ParseStructTag(tag string) (map[string]string, error) {
results := make(map[string]string)
pairs := strings.Split(tag, " ")
for i, pair := range pairs {
if pair == "" {
parts := strings.SplitN(pair, "=", 2)
if len(parts) != 2 {
return nil, fmt.Errorf("missing key in '%s' (pair %d)", pair, i)
results[parts[0]] = parts[1]
return results, nil
// strictUnmarshalJSON is like json.Unmarshal but returns an error
// if any of the fields are unrecognized. Useful when decoding
// module configurations, where you want to be more sure they're
// correct.
func strictUnmarshalJSON(data []byte, v interface{}) error {
dec := json.NewDecoder(bytes.NewReader(data))
return dec.Decode(v)
// isJSONRawMessage returns true if the type is encoding/json.RawMessage.
func isJSONRawMessage(typ reflect.Type) bool {
return typ.PkgPath() == "encoding/json" && typ.Name() == "RawMessage"
// isModuleMapType returns true if the type is map[string]json.RawMessage.
// It assumes that the string key is the module name, but this is not
// always the case. To know for sure, this function must return true, but
// also the struct tag where this type appears must NOT define an inline_key
// attribute, which would mean that the module names appear inline with the
// values, not in the key.
func isModuleMapType(typ reflect.Type) bool {
return typ.Kind() == reflect.Map &&
typ.Key().Kind() == reflect.String &&
var (
modules = make(map[string]ModuleInfo)
modulesMu sync.RWMutex